Which Wood Primer to Use?

I have a badly ventilated house with a poor, or non-existent, damp course. I have painted the wooden window frames with a water-based u/c and t/c previously and I have a lot of newly installed pre-primed skirting boards.

Both skirting boards and window frames are liable to mould growth over the winter. I have been told that aluminium-based paint will help combat this. Can I get this as a topcoat or is it only available as an undercoat? Mike

It’s not a solution I would have suggested, improving ventilation is always the first course of action. I guess there is some weird logic to what you suggest though?

Bear in mind that aluminium paint is not compatible with water-based finishes so you’d need a bonding primer between the two.

Maybe ask the person who recommended this course of action for more info?

I have varnished knotty pine tongue & groove on my utility room walls & ceiling. I would prefer to use water based products & change the colour to Magnolia.

If I were to firstly sand the knotty pine, would a water based primer & water based paint or emulsion be suitable to cover it. If not, what would you suggest? Kay

A water-based primer and finishing coats would probably work OK.

With the walls you may find that a water-based finish takes a long time to fully cure and can be easily damaged with abrasion scuffs and scratches so be careful for a few weeks after painting in order to avoid these.

I have painted a new hardwood front door in Dulux aluminium wood primer. My wife has now found a F&B colour which she wants to paint this in but it is water-based.

Will I achieve a nice finish if slightly sanding down the existing aluminium primer and applying a F&B primer/undercoat (also water based) followed by the top coat of F&B? Many thanks. Chris

Aluminium wood primer is not compatible with water-based paints. What you’ll need to do is apply a couple of coats of oil-based undercoat first and allow at least 2 weeks for this to fully cure.

Then, and only then, you will be able to paint over this with your F&B primer/undercoat and finish.

Hi there I’m getting a new front door made in sapele. The joiner is going to spray prime it using an unspecified water based primer.

I’m not sure what is best to put over the top of that, I have also read that sapele really needs an aluminium primer to prevent bleed through/resin vapour making the top coat bubble?

I want to make sure that the door is well protected against rot and swelling, and ideally want a heritage farrow and ball/little Greene gloss finish.

But these paints don’t seem to say much about how much protection they offer Vs Dulux weathershield etc? My door is east facing and relatively well sheltered with a small canopy porch thing above it. Thanks, Domic

Since you say: your joiner is ‘going to spray prime it using an unspecified water based primer’ I should point out that isn’t advisable. Wood primers should be applied by brush in order to get the best key. Using a water-based primer does also limit your subsequent choices and you should certainly not apply an aluminium wood primer on top of a water-base coating – they are not compatible.

The best exterior paint to use would be Dulux Weathershield since it is formulated for exterior use and offers a great deal of flexibility. The oil-based option will stay shinier for longer; the water-based version can perform better long term though.

You need to sort out the primer situation first though.

Help please. I’m about to paint 2 internal wood doors, sanded to bare wood. I’ve bought, both water based, Dulux Trader QD Undercoat and Dulux QD Satinwood ….. what Primer do I use? I can’t seem to find Dulux water based primer, only water based Undercoat & Primed combined. Thanks, Barry

The primer/undercoat is fine, you can use that although you may need to thin the first coat down a little with water.

However, you need to be careful when priming doors with a water-based primer since it can lead to swelling of the wood initially. It is not certain since a lot depends on whether you are priming hardwood or softwood. Some softwood timbers are very susceptible.

If swelling is likely, I would use a regular oil-based primer (thinned slightly with white spirit). Allow to dry/harden for at least 3 days the run down to a smooth finish and THEN prime again with the water-based QD undercoat (no need to thin this time), then finish with 2 coats of QD satinwood.

Hi. I hung some new softwood garage doors this month (Jan) which had been painted in the house due to the weather. Unfortunately, they warped really badly after they went outside.

I used Dulux Weathershield – 2 coats of preservative/primer, 2 coats Quickdry undercoat followed by 2 coats of Quickdry satin.

I was really careful to ensure all areas were thoroughly covered at each stage. I’m devastated! What can I do?

Maybe wait until later in the year when hopefully the warping has reduced and apply more top coats? I’m confused about breathable paint like this – does it let water vapour in as well as out? (I was expecting it to behave like Gore-tex!)

Thanks – really appreciate your time, Andy

Softwood is highly porous and, in this case, using a water-based system was probably not the best idea since, by their very nature, water-based paints have a high water content and this can cause some timbers to swell and disfigure out of shape.

Some joinery products are also made from very poor quality ‘fast-grown’ timber and sometimes they perform poorly regardless of any paint system used.

Depending how bad the warping is, you may be able to recover the situation by leaving the doors to settle for a while and making adjustments later on using an oil-based system on any areas that need priming again.

No, the colouring of the oil will migrate through. I would remove as much of the residual oil as possible with white spirit, allow to dry out and then prime with a spirit or water based primer. This will seal the coating and then you can use a solvent based finish on top.

Yes, an oil based primer will mitigate the problem. Two coats are better than one also, especially the end grains which are very absorbent.

Hi Mary, It depends how far you’ve got? Also, aluminium wood primer and water-based coatings are incompatible.

So, to answer your question, I’m going to say that if you’ve already painted a large area with aluminium wood primer then carry on with this. Then, to finish, you’ll need a couple of coats of oil-based paint.

Alternatively, assuming it’s a small area, cover this with oil-based undercoat and give a couple of days (at the very least) to cure. Then start again with a water-based finish of your choice.

I am about to paint my old stair case and doors which are varnished. I plan to use dulux satin wood which is water based. Should I use a zinsser primer? If so, how many coats and which zinsser product?

Secondly, I have used a heat gun to take all paint off my front door side panels which now shows a reddish wood.

Again I want to use satin wood water based. What are your recommendations? Many Thanks, Aidan

Hi Aidan, you have 3 issues really:

You need a primer that will give good adhesion to an existing varnished surface.

There is a potential for residue within the varnish and stripped woodwork to bleed through necessitating a stain-blocking coating.

And, you need a good base for your satinwood so you don’t need multiple coats to get a decent finish.

With these issues in mind I’m going to suggest the following:

1 coat of Zinsser B.I.N shellac-based primer which provides excellent adhesion and also stain-blocking properties.

1 coat of acrylic primer undercoat, such as Dulux Trade Quick Dry Wood Primer Undercoat, which also has stain-blocking properties, particularly any oil or resin based stains that manage to get through the coat of B.I.N. This will also provide you a good base on which to paint your water-based satin.

You may find that after using the Zinsser B.I.N you have difficulties getting the water-based primer/undercoat to cover properly. Sometimes a spirit residue will remain on the surface and prevents any water-based coating from properly sticking – what we call cissing.

If this is the case simply give it a few days to properly cure before attempting again and you should have no problem.

Hi I’m painting my hallway, the stairs and door were varnished in mahogany. I’ve sanded everything down and I’ve been told to use an aluminium wood primer to make sure the dark colour doesn’t bleed through.

Question: are all aluminium wood primers silver/grey? I’m painting them white and I can’t seem to find a white aluminium wood primer – I just want to check that it doesn’t exist before I paint it silver!! Emma

You could use aluminium wood primer and, yes, it is typically dark grey or silver.

However, you can make your life a bit easier by using an acrylic wood primer/undercoat. Often sold as ‘quick-drying’ they are water based and white in colour.

A couple of suitable products available from B&Q are:
Dulux Trade White Metal & Wood Undercoat
or,
Leyland Trade Universal White Multi-surface Primer & Undercoat

Anything of a similar description will do though.

The only exception being if the woodwork was treated with a water-based stain or varnish previously, then the colour will bleed through. It’s very unlikely though and easy to test before you commit to buying any. Just paint a small patch with a white or light coloured emulsion paint first to check it dries solid without any discoloration.

We’re having problems decorating a front door. It was painted 2 years ago in F&B gloss paint with no issues but we changed our locks and were unable to touch up as it looked different when we tried the same paint.

We bought a new pot of paint and have recently employed someone to do the door in the new paint (F&B gloss, same colour).

They sanded and applied Zinnser shellac followed by a white undercoat and then the gloss. It looked bad after 1 coat, slightly better after 2 and acceptable after 3. Unfortunately the door wouldn’t then close and after 2 weeks the paint hadn’t set properly.

The decorator returned and had to use a heat gun to remove the paint. I purchased a Dulux Trade gloss and this went oh ok. The door needed rehanging and still doesn’t close properly.

It would be good to understand what may have gone wrong if possible. Was a shellac primer necessary as it was the same paint? Sally

Hi Sally
I am puzzled as to why a primer was used at all, especially Zinsser which is generally only used for covering stains? I can’t say whether this has prevented the subsequent coats of paint from drying properly but it’s possible?

No doubt, the sheer thickness of all that paint has caused issues with door closing and disturbing a previously well-fitted door can cause all manner of problems, as you have found. The door hinges may need packing or the door itself may need trimming and, to further complicate matters, this isn’t an ideal time of year to making such adjustments because of high levels of moisture in the atmosphere.

Obviously, it is impossible to say the original painting job is the source of all the problems but, on the balance of probabilities, it seems likely and your painter really needs to take responsibility for putting matters right.

Yes, generally speaking although you may find the top coat is both difficult to apply (you’ll get a slight ‘pulling’) and the finish will be ‘flatter’. This can ne mitigated, to a degree, by applying extra coats or using an oil-based undercoat over the initial primer.

The correct process would be to strip the varnish and start again with primer, undercoat, etc.

But, if you don’t want to do that, you could use 2 coats of an acrylic primer/undercoat (also known as ‘quick-drying wood primer) followed by water-based gloss? A stronger kind of acrylic primer, known as Zinsser 123, is available if you want to be extra sure it’s going to last.

However, it is essential that you wash down the surface with a sugar soap solution and thoroughly rinse afterwards. Also, rub down the surface to remove any ‘glossiness’. This will ensure the primer sticks properly to the surface, preventing any problems occuring later on.

You shouldn’t use knotting with water-based paints by the way as it can react badly. It is unlikely you’d need to anyway though.

Reading through there’s some great tips here, thanks. I’ve bought a new Meranti traditional style glazed door and just found out the manufacturers guarantee (Mendes) is only effective if you have a 1.5m porch (!).

I’m thinking I will install the door anyway as it is hardwood and mortice and tenon jointed, not doweled. I’ve got a 1m porch and the existing door never gets rained on, but is South facing.

With your previous comments I’m thinking of using water based primer and top coat as it’s possibly less likely to crack with the sun?

And is there any difference between water and oil based paint systems in terms of ‘sealing’ the wood and joints? Is that something aluminium primer does particularly well? Matt

Water-based paints tend to remain flexible for longer than traditional oil-based alternatives which can become brittle over time. Paints specially formulated for outdoor use, such as Weathershield, are also quite flexible though so there isn’t that much between them.

Water tends to get in via gaps in joints caused by natural movement, so the more flexible the paint, the better.

Aluminium wood primer is ideal where you have an oily, resinous wood that may stain some traditional finishes. It’s a good primer to use but, being oil-based, also suffers from becoming brittle over the years. It’s also dark-grey in colour and difficult to cover. So I wouldn’t normally use it unless staining was an issue or the wood was very knotty?

The major difference between oil and water-based paints generally is that you can get a high gloss finish with oil-based paints while water based paints tend to lose their sheen much more readily. If this isn’t a worry then I’d opt for water-based everytime.

With regard to being south facing, I would opt for as lighter colour as possible since they reflect damaging ultraviolet radiation much better than dark colours.

Hi I have a very tall house to paint on the outside only accessible via a cherry picker, there are a number of fascias to be painted, a very large one is more or less down to the wood, the sun fades the woodwork, the rain beats down on those areas. what is the best primer, undercoat, and top coat? I am very confused with the water based paints. Parera

If you are taking it down to bare wood I would suggest using an exterior paint system such as Dulux Weathershield or Sandtex Exterior because they are more flexible than regular paints and last a lot longer. Each have their own specific primers so it’s best to stick to these.

Water-based paints are much the same as oil-based but they dry quicker and are more pleasant to use. You don’t get as ‘glossy’ a finish but water-based paints remain flexible for longer and usually last longer outside than oil-based paints.

Since you mention the sun being a problem, stick to white or light colour shades because they absorb less damaging ultraviolet radiation than dark colours so will last longer.

If it is wood-stain, Yes! Otherwise, standard undercoat.

Yes, you will need to use a primer. Wherever there is high moisture or direct contact with water it is important to prime both sides of the panel and, especially, the edges as this is where most moisture will be absorbed.

You can use any kind of wood primer and top coat combination but, as a rule, if you use an oil-based primer then use an oil-based top coat or use a water-based primer and water-based top coat (often called ‘quick-drying). You’ll need to use at least 2 coats of eggshell to get a decent result.

Water-based paints dry quicker and are more pleasant to use. There is also little performance difference between oil and water based paints these days so either option is OK.

Hi, can I use a water based wood painting on top of an oil based primer? I need to use oil based primer because the wood has an oiled finish that I won’t be able to sand off fully.

I’ve read about a primer which allows you to ‘convert’ From an oil to water based finish but I don’t know type this is or where to buy it. Sarah

Because the wood has an oiled finish some of this is going to migrate to the surface of your primer which complicates things a bit. The problem you’re going to encounter is ‘cissing’ of the water-based top coat. Cissing is when a film of paint doesn’t adhere to the surface so you can’t get a continuous coverage.

You can mitigate this slightly by allowing a few days for the primed surface to fully cure and then cleaning with a sugar soap solution. In mild cases this will do the trick but sometimes the oil contamination is too severe. There are specialised primers that have a higher degree of adhesion (Zinsser 123 is the most widely used) but they are expensive and don’t always work as intended. If the surface is contaminated you’re going to have adhesion problems eventually, even if you manage to get a satisfactory finish initially.

What I would do is make sure the surface is well rubbed-down and wipe it all down with white spirit to remove as much oil contamination as possible. Then prime with the oil-based primer as intended.

Let this cure for a couple of days, rub-down again and wash with sugar soap solution, thoroughly rinse and dry. Then undercoat with an acrylic primer/undercoat (usually called ‘Quick-drying undercoat) and allow to dry. Then finish with your paint of choice.

So long as you don’t have any problems with the acrylic primer you should be ok but there is always a risk, even if you use oil-based paints instead.

Dulux Trade Weathershield or Sandtex (made by Crown) both have exterior ranges in oil and water-based. Water-based paints can be more durable because they stay flexible for longer but oil-based paints give a better, traditional finish.

You could try an acrylic primer/undercoat (often sold as ‘quick-drying’). You will need to wash down the surface and remove all traces of grease and detergent first though. Also, lightly abrade the surface with a fine sandpaper – you don’t need to get carried away, just enough to give the paint something to grip to.

If this is internal you should have a fair chance of success; externally, less so.

You can finish with an oil-based paint but to get a high-gloss finish you should use a an oil-based undercoat first. You can just do 2 coats of acrylic primer and 1 coat of gloss but it will dry slightly flat.

Alternatively, use a water-based (or quick-drying) finish. Again, you won’t get a high-gloss finish but, performance wise, there isn’t much between them. Water-based finishes do not yellow over time like traditional oil-based paints do though so, if using white, there is a slight advantage.

Externally, you can use either again but only use water-based gloss that’s been formulated for outdoor use – such as Dulux Weathershield or Sandtex

Gesso is an an acrylic, water-based primer so a water-based finish, such as quick-drying eggshell or quick-drying gloss, would be the simplest solution.

Yes you can. What you will find though is the first coat of satinwood will dry very flat and this may mean you have to apply more than the regular two coats to get a good finish. It all depends on a lot of variables though so you may not even notice any problem?

The paint is probably a thixotropyic formulation which, basically, means it has a gel-like formula so it can be applied thicker than normal paints without running or dripping. Used mainly for non-drip paints but also has benefits for some primers where you need a thicker than normal coating. Stirring or shaking the paint breaks this gel down into a liquid and, therefore, removes this property.

The problem is that when these paints are left to rest for long periods they do, like most other paints, begin to separate with the oil floating to the top. Stirring the paint and using in its thinner form is better than trying to use it as is. You may need to paint an extra coat to get a decent coverage though.

However, try to stir it until the oily layer has gone and then leave a it for a day or two to settle.

If you can stir it into a usable consistency then you should be ok. However, make sure all the stuff that has settled in the bottom is properly mixed in – it can take a lot more stirring than you imagine. Scrape a screwdriver, or something similar, along the inside-bottom of the can, if it isn’t mixed in you’ll find thick deposits there.

How long an opened tin of paint will last depends on a lot of factors. How much paint was used, how much air is the tin and so on. Impossible to say really.

You would need to remove the stained varnish and use an aluminium wood primer.

Hello, I’ve recently removed all the old paint off my staircase using a heat gun, and taken it to the wood and sanded it down.

I also intend to send the gloss off my doors and undercoat and satinwood it I am going to use the Dulux Trade paint, but should I use the separate oil based primer tin and undercoat tin, or use the water based ‘ wood undercoat and primer’.

I am going to paint it with the water based dulux trade satinwood to prevent it from yellowing in the future.

What paint combination would be the best? Someone I know said to use the oil based undercoat and primer, however, I’m not sure if applying the water based satinwood on top of it is good. Raj

I would use the water based primer/undercoat rather than the oil based primer. It’s just a lot easier in the long run to stick to one system.

The advantage of using an oil-based primer is that although it takes longer to dry it does dry hard so you can sand down to a smooth finish. With a water-based primer you’ll find that your sandpaper clogs up a lot because the paint is still quite soft (even though it has dried). You can mitigate this, to an extent, by waiting a few days before sanding down (which kind of negates the benefits of it being quick-drying).

So, really, it depends on how perfectly smooth you want the finish to be. With a satinwood finish it might not be a priority?

If you do decide to use an oil-based primer, one further complication is that you’ll also need to let this cure for at least a week before applying a water based finish. This is because when the paint dries it leaves a slight oily residue on the surface which makes it difficult for water based paints to adhere to; giving it a few days is usually enough for this to evaporate away.

Never simple, is it?

Part of the exterior wood of my house is painted with oil based paints and needs repainting. A new part has just been painted with a water based acrylic primer and undercoat. All the exterior woodwork is about to be painted.

Will painting all the wood with oil based exterior paint be ok, or could there be problems on the newer water based undercoated section? Robert

No problems, as such, but to get a uniform finish ensure all the woodwork gets a full coat of oil based undercoat first.

If you leave the undercoat to fully cure for a few days the beading (or cissing) should be less of a problem. A light sanding down will also help.

Wood-stains, both opaque and semi-opaque types, are formulated so they are absorbed into the surface of the wood and are not appropriate for covering existing painted finishes.

A water-base opaque stain will adhere to acrylic primer and will probably cover, if you give it enough coats, but the result you want is probably best achieved by using a conventional paint finish?

Yes but you’ll get a flatter, less glossy, finish. To get a good result either use an oil base d undercoat first or an extra coat of gloss.

Hi I hope you can help. I’m a decorator and renovating lots of windows in a beautiful old house. I have had huge success using the Dulux Weathershield system and Ronseal wet rot treatment and filler system… windows I did about 10 and 15 years ago still looking good. This house though has had so many repairs over the years that I have a mixture of different types of woods.

Some of the sills are really old oak and they had a slight sheen on them when I burnt off the old paint. Most of the openers are relatively new and made of softwoods with a lot of wet rot going on.. some of the main outer frame uprights are really resinous, when I used my heat gun on them there was resin pouring out.

I have chatted to Dulux and to my paint shop and I’m getting different opinions on the best primer to use. The carpenter who put in the new sills has told me to use aluminium wood primer on the old oak. Dulux said that if I rub down resinous wood with meths and then see if their preservative primer soaks in to the wood to just use that and not bother with aluminium wood primer..

I rang back and spoke to a different person at Dulux and he suggested the aluminium primer as a safe guard.

My paintshop warned me that aluminium wood primer grins through and it’s hard to cover. I’m finishing with 2 Dulux Weathershield oil based undercoats and 2 oil based topcoats in high gloss. I have read conflicting advice on using zinsser coverstain for exterior work as another recommendation for going on top of my bare old oak and bare resinous wood… some people say it doesn’t last outside.

I have 12 south facing windows all stripped down and ready to prime with something and 16 north facing windows.

So this is a rather crucial part of the procedure to get right. What I’m thinking of doing is to use wet rot wood hardener first so it can get to the bare wood where necessary, then woodfiller, then 2 coats within 6 hours of the Dulux weathershield preservative primer on all the bare wood, then putty, then aluminium wood primer if I believe I need it, then the 2 undercoats and the 2 top coats.

My client is thrilled with the renovation work so far, Old painted shut bobbly bumpy windows will look brand new once painted but I’m extremely worried about this resinous wood and oak, I’ve only ever painted softwoods before. Caroline

Although it can be tempting to liberally use preservative treatments it should be noted that they can leave residues in the wood which may exacerbate resin exudation by solubilising and mobilising the natural resins already present. For this reason you should only employ the use of these treatments to areas where it is strictly necessary.

Concentrations of resin in hardwoods will always force their way through to the surface no matter what you do, especially when exposed to direct sunlight. All you can do is mitigate the inevitable and accept that you may have to repaint more often than you would otherwise.

The best practice is always to use an aluminium wood primer and to avoid dark shades of finishing colour. If a dark finish is preferred then a dark woodstain should be used instead.

Two coats of oil based undercoat should be sufficient to cover the dark-grey aluminium primer but don’t be afraid of employing as many coats as are necessary.

The good news is that concentrations of resin are finite so the problem will not persist. However, since it sounds like a fair degree of repair has already been necessary, it may well be that your client will have to accept that bringing everything up to ‘as good as new’ is not practical and a program of ‘managed decline’ is more realistic. A regular touch-up every two years or so may well be the best way forward?

Yes, turps or white spirits are what you use to thin solvent based paints. Add only a small amount at a time and stir well so the paint is thin enough to soak into the surface but not so thin that it is like water. Don’t try and add 20% straight off as it’s easy to add a bit more thinner if you need to.

Yes, it’s often referred to as ‘quick drying’ rather than water based, hence the confusion. You can use standard oil-based paints over a water based primer but you’ll get a better result if you stick to one base.

Water based finishes are available in gloss or mid-sheen. Ask in the shop if you are not sure which is which.

It’s possible this is a factory applied finish and may be cellulose based, used mainly in such situations because it dries quickly. The safest solution would be to use an adhesive primer like Zinsser, which is water-based and unlikely to cause any problems.

Or, you could try an isolating primer like Barcoat that reacts with the surface to form a bond. This works well in some cases but can react adversely with some paints. It’s wise, therefore, to use with caution and do a small trial area first.

Hi, I am just about to start painting our traditional timber cladding, rough sawn treated feather edge boards.

I have bought aluminium primer to avoid staining coming through, however my top coat is a water based satin.

Can I use a suitable undercoat over the primer which will allow me to use the water based satin colour finish? Dexter

I wouldn’t recommend using a water based finish over an aluminium wood primer but, since you got this far, I suggest using a regular oil based undercoat as a bonding agent.

After applying leave for at least two weeks to fully cure. Then apply a coat of water based acrylic undercoat as an adhesive (avoid the primer/undercoat variety if you can as it’s a bit too thin for this purpose). Then apply your top coat.

Ideally you should use a water based varnish but if you want to use a regular oil-based varnish you should be OK provided the paint has fully cured (for more than 2 weeks). It’s unlikely but do a test area in all cases just in case there is a reaction.

I don’t know what you mean by ‘garden paint’ but, as a rule, you should avoid using water based paints over oil based primers. However, provided you allow the primer to fully cure before applying the water based finish you shouldn’t have too many problems.

By ‘fully cure’ I mean letting the paint harden over a period of a couple of weeks rather than just waiting 24 hours for it to be touch dry.

However, you may experience ‘cissing’ of the top coat; which, basically, means the paint refuses to form a continuous film. In which case, depending on the severity, you may need to apply extra coats or, in severe cases, revert to using an acrylic primer/undercoat.

The longer you leave the primer to cure though, the less likely this is going to occur.

As you probably know already, cellulose paints can react aggressively with other forms of paint coating so this should be avoided, if at all possible. It’s not a common problem in a domestic setting since not many finishes are cellulose based – Hammerite is the odd exception.

If the use of a cellulose based finish is unavoidable you’ll need to use a yellow oxide isolator such as Barcoat.
http://www.u-pol.co.uk/documents/datasheets/tds/BAR-TDS-US.pdf

You can buy this from industrial and auto paint suppliers or from amazon.

As always in these situations, try a trial area first since results are unpredictable.

The main problem you’ll encounter is adhesion of any paint covering, no matter what you use, so the most important preparation is to remove as much oil and wax from the surface as possible. Wire wool and white spirit will be the most effective way of doing this.

You could use an aluminium primer, which would prevent any staining, but I’d advise you try a sample area first and see how you get on.

Tried to paint a bath panel with Little Green Traditional Eggshell over two coats of Zinsser 123, but the oil based eggshell became sticky very quickly and I really struggled to brush it out.

Was it reacting with the 123 and should I have used an oil based primer or undercoat?

I actually gave up and started again using Sikkens water based primer and topcoat. However, I would still like to know what I did wrong, the LG paint was £28 per litre. Terry

It is possible there was a reaction between the two finishes but it’s hard to say. No doubt Little Green would just refer you their application instructions and absolve themselves of any responsibility.
http://www.littlegreene.com/media/wysiwyg/data-sheets/TRAD_OIL_EGGSHELL_Data_Sheet_2016_04.2016.pdf

However, it could also be possible that the Zinsser had not cured fully before you painted over it. Although they say you can over paint in an hour I would always advise leaving at least 24 hours when using a different base of finish (longer, if at all possible). Zinsser kind of cover themselves in this regard by adding ‘Full adhesion and hardness develop in 7 days’. And, also, by stating:

Bulls Eye® 1-2-3 is guaranteed to perform as indicated when applied according to label directions to a properly prepared surface. Directions are as complete as possible but cannot encompass all conditions, applications, and / or surfaces beyond manufacturer’s control. The contents of the container are warranted to be free from any other defect for 2 years from the date of manufacture. All warranties and guarantees are limited to refund or replacement of product used with proof of purchase.

http://www.zinsseruk.com/wp-content/uploads/2012/05/Bulls-Eye-1-2-3-Water-Based-Primer-Sealer.pdf

That said, it may be worth your while getting in touch with them as they may refund you as a good will gesture?

William Zinsser (UK) Ltd
Portobello Industrial Estate
Birtley
County Durham
DH3 2RE

0191 410 6611

Hi, after sanding down oak kitchen units which were oiled , I then applied two coats of zinsser (the red can ), after allowing it to dry and sanding it , I then applied two top coats of dulux diamond eggshell , followed by furniture wax.

However after a few days the paint is beginning to chip off , could you advise me on how to fix this or a better primer / undercoat? Debbie

Zinsser is one of the better primers you can use in this situation so it’s likely the problem with chipping paint is a combination of two other things. Firstly, it may be that the surface of the wood still has some oil residue which is affecting adhesion. Also, paint can take a long time to fully cure even though it appears to be dry – sometimes a few weeks.

Rather than do anything rash I would be tempted to wait a couple of weeks and see if the paint performs better when it has fully hardened, in which case you may be able to touch up any chips.

Failing this, you would have to remove the paint and start again, making sure you’ve removed all traces of the previous oiled finish.

Once you’ve started with a water based sealer it’s best if you stick to the same one. You will find your gates swell and contract naturally since they will absorb atmospheric moisture to a certain extent anyway, especially via the end grains which are seldom properly sealed.

I wouldn’t do anything right now since the gates may contract when the weather is warmer and there is less atmospheric moisture. In the summer do any trimming/planing you need to do and then have another go, making sure you cover every edge and surface. And, always, allow a little bit of leeway for natural movement throughout the year.

Probably not no. The best thing to do with glossy surfaces, if you can, is to rub down with sand paper to remove as much of the sheen as you can. Depending on how well you do this, you can use an ordinary undercoat for the first coat or a specialist difficult surface primer such as Zinsser

Likely the table already had some form of coating or sealant already on it – it isn’t always obvious, particularly with factory applied finishes. Some surface contamination may have also compounded he problem further?

OK, assuming you want to provide a suitable base for a dark coloured stain you have a couple of options:

For interior use a thinned coat of clear water based varnish will act as a suitable surface sealer. For exterior use I would opt to use a very light shade of the same wood-stain first followed by your darker shade of choice.

There are specialist products such as Aquatech Preservative Basecoat but I would advise caution since you can sometimes get an adverse result when using with other brands of water based finishes. By all means try it but on a test area first.

I have a plywood desk that i made for a sound booth. I purchased it with one side sanded already which is the aide on the top of the desk. I want to put a light stain and poly over it to protect from spills. What primer can I use so the stain goes on even? And also the legs are made from PT 4 x4 wood posts – how would i do those as well? Pat

You can use any brand of sanding sealer to seal the wood before staining, one coat should do the trick. Liberon 250ml is the cheapest on amazon although you may be able to find cheaper locally? A thinned down coat of clear finish is a budget option but requires a bit more skill.

Yes. Ensure the surface is thoroughly cleaned with a sugar soap solution first though. You may find the finished coating is not as durable as if you had completely stripped the door and started from scratch but, for domestic use, it shouldn’t be too much of a problem. Paint cures and hardens over time so try and protect the finished paintwork for a week or two if you can.

I want to paint my stair spindles a sheen water based paint finish. They are hardwood and some are stained with a colron wood dye and some are not.

However they are ALL varnished over. I intend to sand back to remove as much of the varnish as possible.

The surface is in a good sound condition. I have been told that I will need to prime and or undercoat the spindles (prior to top coat) to seal the stain/varnish. I am not quite sure how to proceed and what to use?

Can you help please? (I do not have a lot of time for a long drying process!) Nigel

If you remove the varnish then a water based acrylic primer or combined primer/undercoat should be OK. You’ll need to do a small test area first to check if any stain continues to bleed through; if it does then use an oil based primer instead.

It is possible that you could just paint over the spindles as they are though. It really depends on the condition and how good a job you want to do but, if it’s just the final finish you’re concerned about, it may be worth a go?

Use an acrylic primer/undercoat as your primer and then finish as desired. Obviously the more preparation you do before hand the better.

And a thorough cleaning with a sugar soap solution followed by a light sanding should be the absolute minimum.

There isn’t much you can do; just use regular undercoat and gloss instead. The alternative is to try and sand off the primer or tell your joiner you want new doors – either way it’s going to be messy.

For best results you’d need an oil based primer and finish because water based paints will make the strands swell and stand out more than they do already, so it will be difficult to get a smooth finish. But, if the final appearance isn’t important you could use a water based primer for the first coat and then one or two coats of masonry paint to finish.

If you are painting for aesthetic reasons only it doesn’t matter so much but if it’s for preservation and durability you should consider painting both sides of the boards and sealing all edges to prevent the absorption of moisture.

Help needed please. I’m decorating a brick conservatory tacked onto a small terraced bungalow I have purchased. It was obviously a cowboy job and my present task is tidying up what was the exterior wall before the room was constructed.

It was just covered with some thick paint not sanded or smoothed or made presentable. I’m using hardboard panels, which I am fixing with contact glue and masonry nails, as this seemed an easy way to achieve a smooth surface but I intend to paper over it to match the other two plastered walls.

Question is what do I prime the hardboard with before I paper; there seems to be a number of different primers? Suzie

Cheapest option is any kind of emulsion paint. You could use a water based or oil based wood primer instead but, in your case, it’s not going to make much difference.

The joints in your panels are going to need reinforcing though. A self-adhesive scrim tape is going to be the cheapest option although you will get raised areas under the paper. You can buy lining paper that has a cotton scrim stuck to the back though; it’s expensive but you might not need that much of it and you’ll get a decent result that should resist any movement.

I would like some advice please. I’ve sanded back some wood beading and paneling in a bedroom in parts back to the bare wood. I’ve cleaned it all down.

I used a dulux wood primer and undercoat (all in one) but as soon as I put it on I noticed it turning a creamy colour particularly on the areas where I’ve exposed the bare wood whilst sanding.

I took advice from some guys at B&Q who have told me to use a higher acrylic based all in one primer and undercoat. They suggested valspar. They told me to lightly sand the area down before applying a coat of this new stuff, then to let it dry before lightly sanding down again and applying a 2nd coat.

Well so far I’ve got to applying the first coat of the new valspar product and I can still see the creamy yellow tinge starting to appear.

Please tell me what to do to sort this out as ultimately I am looking to paint them in an eggshell water based paint in a light grey colour but I’m afraid the top colour will be tinged with the staining that’s coming through. Do I persevere and put a 2nd coat on or am I wasting my time. Any advice will be greatly appreciated. Claire

Yes, you will be wasting your time adding another coat. The people at B&Q ought to refrain from giving advice on subjects they know nothing about.

The wood has a waterborne stain and any subsequent coats of water based paints will dissolve it and allow it migrate through to the surface. A coat of oil-based paint will stop this happening; simple white undercoat will do the trick and then you can continue as before. There are some spirit base ‘stain-blocking paints’ that do the same thing but you’ll have to judge for yourself whether it’s worth paying the extra.

However, to avoid any compatibility problems, you’ll need to let the undercoat fully cure before over-painting with a water based finish (a full week, if you can wait that long?). Less time if you use a spirit based product but still wait as long as you can.

You can use a water based primer but to achieve the same finish as the rest of the porch you’ll need to complete the work with an oil based undercoat before glossing. I say this because a lot of water based primers can also be used as an undercoat but an oil based gloss directly on top will often dry ‘flat’ (without a gloss) and need more coats than usual.

I just bought a bare wood backdoor want to use the dulux weather shield system and go with a satin finish, the brochure states that bare wood needs 2 coats of exterior preservative primer so have done that but can’t work out now if I need to use undercoat before using the quick dry exterior satin the booklet says no need but the cans say 2 coats of undercoat any ideas? Jon

No, the exterior satin can be used coat-on-coat so just apply two or more coats to get the desired finish. In other words, the first coat is the undercoat.

Help please , I am redecorating a hall and stairwell which has a ceiling height of over four meters. The walls are covered in wallpaper which I intend to paint over. The idea is to save time and money.

I understand I should prepare the walls by priming the existing wallpaper with an oil based primer and then give a light sanding prior to applying paint. Is this the best way to go about it and if so please advise which primer would be best for the job. Mr Bryce

In principal you are correct but since it is such a large area I think it is wise to take a few precautions.

Firstly, painting over an existing wall-covering is always a risk since you never know how well it is stuck to the wall, you only find out once you paint it.

Also, using an oil based primer will prevent any stains migrating through to the final finish. And, because oil based paints dry harder, this will make it easier to sand to smooth finish.

But, painting such a large area is going to create a lot of odour that’s going to hang around for quite a while and you don’t want to go through that unless you really have to. It would also be quite annoying if you later discovered the paper wasn’t stuck so well and you had to strip it afterwards?

What I would do is paint maybe the largest wall first with a coat of regular emulsion and then see the next day what the result is. If it is satisfactory you could go ahead and complete the job this way. It’s definitely worth a try. It may be that can get away with just spot priming a few stains here and there, or you may not even have to do this at all.

If you do have to resort to priming the whole area a basic white undercoat will do the job just fine. You can buy special primers, such as Zinsser Wallpaper Cover-Up, but they do much the same thing and cost a lot more money.

Also, ensure there is plenty of ventilation and don’t try and complete the job in one go – keep going outside to ensure you are getting fresh air too.

You could be I wouldn’t recommend it. If you do, try a small area first just to make sure there isn’t an adverse reaction.

I have sanded down to bare wood the front door of my Victorian house . I want to know how to get the best shiniest finish . Should I use aluminium primer with oil based undercoat and gloss?

And if spray painting with a top coat of oil based gloss , do I need to thin the gloss paint and if yes would that be with white spirit? Candy

If you want a high gloss finish then an oil based system of primer, undercoat and gloss will give the best results. I wouldn’t use an aluminium wood primer unless really necessary, for instance if the door is teak or mahogany or some other wood with a lot of knots in in it?

The ideal system is one coat of wood primer, 2 coats of under coat and 2 coats of gloss. The more coats of gloss, the deeper the finish. Also, I wouldn’t contemplate using a spray application unless you have prior experience; your question about how to thin gloss suggests you don’t have any (yes, it’s white spirit btw).

It’s also worth pointing out that the gloss coat will only ever be as good as what is underneath it, a lot of people skimp on preparation and then wonder why the end result isn’t as good as they thought it would be. So your undercoat needs to be perfect and rubbed down to a smooth finish, and all traces of dust removed, before applying any gloss.

I recently prep’ed a hard wood door and frame which until now was varnished. Burnt all the old varnish off, sanded, cleaned ready to go. Bought what I think is a half decent Roseal white water based primer.

Trouble is after one coat the white is discolouring. Bloomin annoying as this primer is said to stop that /be a sealer etc. Can I now rub this down and go with an aluminium primer. Would the two be happy to mix?! And would that potentially cure the problem and stop the bleed through? James

What’s happening is that there was a water based stain already present and it’s become soluble with the use of a water based primer. A coat of oil based undercoat will stop the stain coming through and provide a sound base for subsequent coats of oil based finish.

If you opt for a water based finish you are going to experience this problem at every stage.

Hello, I have been advised by our joiner to use aluminium primer to cover a wooden porch that looks mahogany and was varnished, though is now badly weathered. We want to have a satin finish eventually.

Should I use a satin/water based primer over the aluminium before I paint the top coat in dulux weather shield satin? Thanks, Rachel

You shouldn’t use aluminium wood primer unless you are using a traditional oil based undercoat and gloss system. If you want to finish with Weathershield satin then you should use the Weathersield primer and undercoat instead.

Ensure that any remaining varnish is completely removed before doing anything though. And, if the wood is weathered (usually grey or silver with cracks along the surface) any paint system will fail prematurely – so you’ll need to repaint every couple of years at least.

The water-based Weathershield system tends to be more durable (because it stays flexible for longer) and will probably be your best bet in this instance.

We have 18 oak window frames in a period house that were installed circa 25 years ago. Most of them were treated from the start externally with Sikkens HLS and Cetol Filter 7 (light oak) and have been retreated occasionally since, using the same products.

Several of the sills now have fissures in them along the grain where the oak has weathered, and there is some rot in the joints, underneath the casements. The uprights don’t show any rot, but mould has taken hold where the stain has flaked off.

As I am now having to replace the double-glazing units, many of which have blown, it’s time for a major overhaul.

I have sanded down the frames to remove the old stain, and as much of the grey wood as possible, but the unevenness of the surface makes it impossible to remove all the rot by sanding down, especially from the fissures in the sills, some of which are 2-3mm deep.

My plan is to use a fungicidal wash followed by a wood preservative, together with a wet rot wood hardener on the sills, and then to recoat with Sikkens as before.

I’m filling the rot under the casements with two-pack filler, but I’m not planning to fill the fissures in the sills (a previous attempt to use filler on an exposed area of one frame, to fill a deep crack caused by a shake in the timber, was a dismal failure, as the filler came loose within a year or so.

Also, the two-pack fillers all seem to be pale in colour, so the filled areas show up badly through the wood stain).

My question is, am I wasting my time trying to re-stain these old frames? Do I need to fill all the fissures in the sills before restaining, and if so, can you recommend a filler that will do the job (ideally one that is darker in colour)?

And if restaining is a lost cause on these old, weathered frames, can you suggest an alternative treatment I could use? Gareth

Once hardwood becomes denatured, characterised by the greying and cracking you describe, there isn’t much you can do that’s going to stand the test of time. It’s more a case of managed decline than an an all-out repair.

The treatment you propose is about the best you can do but you’ll have to accept this is going to something you’ll need to repeat every couple of years or so.

All wood fillers will fail eventually when used externally although Toupret tend to be one the better brands. The problem with getting the final colour to match is a common one although you could, maybe, opt for an opaque stain rather than a semi-transparent one?

They perform just as well as you should be able to get a finish that’s someway acceptable. The only other option is to revert to standard paint.

I’m looking to paint over hardwood (mahogany I think) patio doors and window frames, both inside and out. We want a white (or near white) satin/matt colour for the interior surfaces, and a dark grey satin/matt for the exterior.

I’ve previously treated the exterior surfaces with Sikkens HLS Cetol stain. Interior surfaces have a smooth feel – so I’m wondering if there could be some sort of waxy top coat. The exterior stain has tended to flake off – could this be because of a waxy top coat?

What sort of preparation and treatment do you recommend for interior and exterior? Could I go for a water-based treatment for the inside surfaces and an oil-based one for the (very exposed) outside?

I’m guessing an oil-based solution is needed for the outside, using an Aluminium based primer or one of the Zinsser products. I don’t mind buying the more expressive products to get the job done right. Wyn

Water based finishes can prove to be more durable for exterior woodwork because they remain flexible for a longer period of time; traditional gloss gives a better finish but becomes brittle leading to early failure. Dulux Weathershield gloss (if you want a an oil based finish) is better though since it is formulated to accommodate the natural movement in timber. Sikkens also do a range of opaque finishes called Rubbol, both satin and gloss, that perform equally well.

I wouldn’t worry too much about using the same system on both sides of the doors. The only issues you’ll encounter are a possible loss of adhesion, as you mention above, and the likelihood of the stain bleeding through the new painted finish and causing unsightly staining. Aluminium wood primer will solve this problem, as will most acrylic, water or spirit based primers (like the Zinsser products you are aware of).

Preparation is, of course key, and it’s essential you remove any loose coatings to start with as well as ensuring the surfaces are fully cleaned with a solution of sugar soap and then rinsed with clean, warm water.

We have built a detached garage, it is of concrete block construction clad in rough(ish) timber weather board. Without researching it we first used two coats of water based primer / undercoat and then two coats of Dulux weathersheid water based top coat.

This was completed about a year ago. Since then, we have reached the conclusion that a lighter, off white colour would look better than the rather yellowy cream it has become and also there are signs of the timber resin seeping through the finish.

We don’t have the resources to sand the entire building back and go through the knotting solution etc, can we just go over as is with a couple of coats of oil based timber paint, or re-prime with aluminium primer and then top coat in water based or oil based top coat? Claire

You shouldn’t use knotting solution with water based coatings as it isn’t compatible, the same goes with aluminium wood primer.

If the staining is really bad you could use a water based stain block over these areas and then repaint with the colour of your choice.

I have painted an old victorian front door with a Farrow and Ball unercoat and exterior eggshell after having lightly sanded said door. After a few days, tiny bubbles have appeared in various places.

I started the whole process again of sanding back to old paint, use FB undercoats and topcoat again. After a few days, bubbles have appeared again. Not sure what to do. Have done some research online and seen this has happened before.

What is the solution? Using an oil undercoat with water based FB or ditch the wretched FB paint altogether and go for an all oil based solution? Oliver

Hard to give a definitive answer but it could be something simple like applying the second coat before the first has fully cured?

It’s also possible there is some surface contamination from the previous finish. You say you lightly sanded it down but, assuming it was a regular gloss finish, it would need better preparation than this.

Using water based finishes over previously oil based finishes can often be problematic. If you want to still use the same paint it might be worth experimenting with a solution on a trial area?

Take an area that’s badly affected and sand down lightly so you have a smooth surface again. Wash it thoroughly with a solution of sugar soap and rinse so all residue has been removed.

Apply a regular oil-based undercoat to this area only and leave at least 3 days. Assuming there are no bubbles give this a light rub down and apply a coat of the F & B undercoat then leave a full day. Again, if there are no problems, finish with a coat of F & B eggshell. If there are still no problems this will be your solution.

Alternatively, if the above doesn’t work, you could revert to a standard oil based system and just colour match the F & B finish you wanted.

I do a lot of artwork on plywood panels. Normally I use a quick-dry primer/undercoat then apply an acrylic gesso before i paint on top.

However, I have just primed a panel with oil based primer (my fault,poured it before reading), and am concerned an acrylic based paint will peel. Best to sand it back? Or can i leave to cure and then put an acrylic gesso on the top? John

I’m not familiar with geso, in any form, but when applying water based paints over an oil based surface it’s always best to ensure the previous coating has fully cured first. In the case of an oil based primer this can be at least 2 – 3 weeks. Abrading the surface with fine sandpaper will also help ensure the acrylic bonds properly.

I would suggest an acrylic/water based primer. If doing so you don’t need to use knotting solution, it can react with water based finishes and, also, you don’t get the same degree of staining you would with an oil based finish.

However, if the knotting is severe I suggest you use knotting as planned, prime with an oil based primer and then one coat of oil based undercoat. Leave for 2-3 weeks for this to fully cure and then use the water based eggshell as planned. You may need extra coats to get the desired result though, in which case use a regular oil based eggshell or satin finish instead.

Yes, specifically a metal primer containing zinc should do the trick.

I have a new wooden gate, untreated. Before painting with Farrow and Ball primer and eggshell water- based paint I want to use a wood preservative.

I have had experience of using a clear preservative, before painting as above,with bad results where the preservative seemed to form a “waxy” type of finish when the paint was applied.

Are there preservatives specifically designed to go under water based paints? Adrian

You could use something like Dulux Weathershield Exterior Preservative Primer that’s a bit of half primer, half preservative? But, generally speaking, you are always going to have problems.

Ideally if you are going to use a wood preserver it’s a good idea to give the wood a good soaking and then leave it sometime before painting. This gives the preservative plenty of time to dry out fully and will eliminate the problem of surface contamination to a great degree.

It’s hard to say how long this should be though because it depends a lot on the type and quality of the timber and how exposed it will be to the elements. I’m thinking in terms of weeks though rather than hours or days if that helps?

There are loads of water based alternatives available that have much less odour. You will need more coats for a decent finish and to retreat more often, maybe every couple of years, though.

Ronseal Fencelife and Cuprinol Ducksback are popular although there are plenty of alternatives.

I recently built a Tardis. It is made mostly of softwood from b&q and plywood for the roof and panels. There’s also lots of exterior wood filler covering countersunk screw holes.

I painted it with two coats of Dulux weathershield White undercoat and three layers of dulux weathershield Oxford blue satin, all water based, I then gave it two coats of Rustins clear exterior varnish.

First of all the colour quickly became white speckled but after a few days of heavy rain, bubbles/ blisters appeared in four different places, I scalpelled them off to find completely bare wood (all layers had lifted). I quickly dismantled her and took her back in the garage.

I’ve now stripped her down to bare wood completely with a heat gun. It has taken a long time but I don’t mind.

The thing is when I paint it again it has got to be properly. I can’t keep taking it apart and stripping it every time there’s a problem.

I did some research and found out about knotting, there are knots in places but not below any of the blisters that appeared, I’ve got some knotting solution but it says not to use beneath water based stuff.

Also I didn’t use primer just ordinary undercoat. And I’ve read about cleaning with white spirit before painting to remove contaminants.

Being that I’m starting from bare wood again can you tell me where to start and finish. I really have to do it properly this time. Colin

The exterior varnish was likely to be the problem since it would stop any trapped moisture escaping. I would have used an exterior gloss, such as weathershield, rather than satin.

You should also have used a primer. And, because you have plywood panels, it’s wood also be a good idea to ensure the inward facing surfaces are also painted, wherever possible. Plywood is notoriously difficult to seal from the weather and you need to ensure that every possible surface and edge is properly sealed – even if not visible.

We have just moved into a Victorian home with a 6 yrs old softwood conservatory which now needs redecorating externally. It was originally finished with Witham Woco water based joinery topcoat which has a slight sheen but this is no longer available from the manufacturer.

Can you recommend a preparation and finishing system? Also, the rest of the sash windows are oil based gloss in fair condition, would you advise sticking to oil based although water based would be easier and quicker to apply? Laurence

There are a few satin finish coatings available and preparation should be straight forward. Wash down the existing coating and lightly abrade to remove any rough edges (much less than you would for regular oil based finishes).
A couple of decent options are:
Sikkens Rubbol Satura Plus and
Sadolin Superdec Satin Opaque

In answer to your second point, you could use a water based system over an oil based finish but the level of preparation is much higher. You’ll need to ensure all surfaces are thoroughly washed down and any gloss is abraded so it is totally flat in appearance before overcoating with a water based/acrylic undercoat.

My general rule though is not to switch from one system to another if you can avoid doing so.

I’ve recently moved into a new build and to add a bit of character I’d like to add mid-height wooden wall panelling to the downstairs toilet (very small – not overly used and adequately ventilated/heated, considering the only moisture would come from splash back from people using the sink).

Please could you recommend the type of wood i should be using and how to properly prime, paint and finish the panels.

I’d ideally like them matt white although the room only has a small window and I’ve seen a previous comments about, and have experienced, yellow tinging on white – can this be avoided? Alex

The choice of wood should be the best you can afford really but since you’re going to paint it anyway I wouldn’t go overboard. Standard pine will do the job just fine – avoid MDF though as it will absorb any moisture in the air like a sponge.

The yellowing you describe is a characteristic of traditional solvent based paints and is most severe where there is a lack of natural light, hence bathrooms are particularly susceptible. However, since you don’t envisage a problem with excessive moisture you should be OK to use water based paints which do not suffer this problem.

If a matt white finish is what you are after I’d have a look at opaque wood stains rather than paint. This way you don’t have to worry about primers and undercoats.

Dulux Weathershield Quick Dry Opaque is an example, there are lots of similar alternatives available.

It is good practice to give the wall facing side of the wood at least one coat and it’s especially important to ensure the end grains are fully sealed by giving them at least 3 generous coats.

Give the main, outward facing, sides as many coats as you need to get a good result but 2 or 3 should be fine.

There are 2 problems here. Firstly, when using quick dry paints over a gloss finish you have to abrade the surface sufficiently to provide a key.

Also, if you have used an oil based primer and undercoat these need to cure fully before applying a water based finish. Not just dry but fully harden and this can take a few days.

Leave it a few days, give the surface a quick rub down and try again. A coat of quick dry undercoat will also help, but see how you go.

We have a boxing in unit made of MDF next to what appears to be a leaking shower seal. I’d like to protect the area and wood to prevent future issues (water ended up penetrating the wall).

What primer would you recommend for this? I also have wooden window frames, that are in contact with water from the shower. I’d like to repaint – again, what would you recommend for this? Thank you, Nick

I’d fix the shower first. However, you use a primer to seal the surface in preparation for further coats that provide the actual protection. So, in this regard, use any primer you want (although acrylic is probably the most appropriate for mdf) but ensure you finish with at least 2 coats of oil based gloss to shed any water that’s hitting the surface. The same applies to your window frames.

If you can remove the boxing-in fairly easily it might also be worth painting the inside surfaces and any exposed edges too.

We have some beams that are rough and stained black. We want to have them glossed. Tried undercoat and gloss (3 coats of each!) but black still showing through.

Have been recommended 2 different things by 2 different people. 1) shellac based primer; 2) aluminium based primer. Which would be best for sealing the black away?

Which could go over what we’ve already done? Darren

You don’t say but I’m guessing you’re painting them white and you are using a traditional oil based undercoat and gloss?

What’s happening is the solvents in the paint are dissolving the original stain and allowing it to bleed through.

A shellac (or spirit based) primer or an aluminium wood primer will work but there is an easier option. Use a water based acrylic undercoat instead (not a primer, because it will be too thin) and then finish with a coat of oil based undercoat and gloss.

Just ensure the oil based finish has had at least a few days to cure before overpainting with the acrylic.

If I’m wrong in my assumption and you are using water based finishes just reverse the above and use an oil based alternative.

The problem with wood paneling is the end grains tend not to be adequately sealed and this is how moisture gets in and causes problems.

But, to answer your question, you can use an acrylic primer but you’ll get a better finish if you use an oil based primer.

Provided all traces of the wax oil have been removed, you should be OK.

Having a new veneer external door hung, in small exposed porch. Manufacturer advises no wax, polish or oils.

Don’t fancy varnish. I’m worried re: wood expanding and jamming, less concerned about appearance. Can I use an acrylic primer and acrylic top coats safely to protect from expansion? Steve

Probably, although you should contact the door manufacturer first because only they know what the door is finished with.

Use a water based undercoat or spirit based sealer then undercoat again and it should be OK.

Zinsser Bin is expensive but quite good. A cheaper option will be to use any brand of water based primer/undercoat.

Because you’ve already use an oil based undercoat you’ll need to let it cure for a few days before overcoating with a water based product I’m afraid. You’ll have problems getting it to cover if you don’t.

For resinous hardwoods, such as teak, you should have used an aluminium wood primer but since you’ve already progressed beyond the priming stage the method above will do.

It is best practice to use a either all water-based or all oil-based paints, especially outside.

You might get away with it if the area isn’t too exposed though. You will need the primer/undercoat to cure fully before overcoating it with a water based finish though, so leave it at least a couple of days between coats – longer, if you can?

Hi, I am wanting to paint some pine wood with water based primer and overcoat. However there are quite a few knots in the wood, so I understand I need to use knotting solution.

I have two at home (Rusting white Knotting and Jewson knotting solution), the Rusting categorically states not to use under water based paints, the Jewson doesn’t mention anything.

Please would you advise how to prepare knotted areas where water based paints are to be used? Saskia

Water based paints can react with traditional shellac knotting. This can result in staining that may be worse than the knotting stain you want to prevent, especially where the finish is a light colour, especially white.

White knotting contains a bleaching agent so it dries clear and will not discolour light colours of finishing paint. It is safe to use under water based paints although it’s advisable to lightly abrade the surface, when it has dried, to aid adhesion. I haven’t experienced any problems with this approach in the past.

However, I have been in touch with Rustins and they have found instances where solvent additives commonly found in water based paints have reacted with knotting of all types and their advice is not to use it.

They say that water based paints do not solubilise the colours from the wood, as oil based paints often do, and, therefore, use of knotting is not necessary.

In my experience I have found this is true to an extent but not 100% so. I think it’s always worth using knotting in cases like you’ve described.

I guess the answer is to try a small trial area first, with and without knotting, to see if you do have any problems, although I’d be surprised if you do?

Sorry I can’t give you a more definitive answer.

There are a couple of situations where you should always consider using knotting. One is on new wood and the other is where the wood is going to be exposed to sunlight.

Since your staircase doesn’t isn’t affected by either of these issues you are probably safe to carry on without it. There is always a slight chance you’ll get a bit of discoloration over time, particularly with white paint, but it’s unlikely to be severe or particularly noticeable.

Sure, you can do that. To get a better finish you may need to give it a coat of oil based undercoat first though.

In Feb 2014 I painted 7 doors with Dulux Professional Brilliant White gloss. Took the doors all the way back to bar wood. Burn off old paint and sanded down. Used Aluminium primer – 1 coat. 2 coats of Dulux Professional oil base undercoat and 2 coats of Dulux Professional PBW oil base gloss.

I now (Oct 2015)find that where the doors (internal cupboard and behinf dressing gown handing on door) do not get very much (or any) sunlight – they have turned a yellowey hue.

I read lots about teh issue Dulux (AzkoNobile) had when they initially were forced by EU rules to reformulate their oil base paint VOC mix.

I saw before I decided to use the Dulux oil base gloss that the yellowing issue was sorted out. Do you have any views on why the areas getting no sunlight have yellowed / areas getting plenty of sunlight are still Brilliant White and glossy.

Should I take this up with Azko-Nobile / Dulux. I feel I should. BTW the painting I did back in 1996 using Dulux PBW oil base gloss is still very white and much whiter than the yellowed new paint which is only 18 months old.

I would have expected at least 5 to 10 years of PBW “colour”. Steve

Oil based paints will yellow to a certain degree when shaded from sunlight, this has always been an issue.

The problem you refer to with Dulux was indeed well publicised and they did make changes to their formulation to mitigate this. It’s clear, however, that the changes made still do not result in their gloss performing as well as it used to.

It is certainly worth taking up with Dulux. I’m guessing they will say your case is an extreme situation and may offer you something as a goodwill gesture. If they do not you are well within your rights to take the matter further via trading standards or directly via the courts.

Our exterior wooden windows and sills need repainting. The condition of the paintwork varies, Some of it is OK, but The south facing sills in particular are very bad, with flaking paint, no paint and open grains/cracks.

Can you advise which is the best primer to use. ? Our neighbour thinks Aluminium based primer is the one – but your advice would be welcome. Mike

Aluminium wood primer is fine for hardwoods but on soft wood it doesn’t perform very well at all.

The main causes of paint failure on windows are ultra violet radiation (from direct sunlight) and/or a high moisture content. Direct sunlight is the likely culprit in your case. The open grain you describe also suggests the timber itself has become denatured making any subsequent paint coating much more likely to fail.

I’d suggest two coats of water based acrylic wood primer. Acrylic primers have a superior adhesion and stay flexible for much longer than their oil based counterparts – and are more pleasant to use. I would go for a pure primer rather than the combined primer/undercoats which are more commonly available. Buying the best quality you can afford is also a good policy.

After priming you could go for a water based finish or conventional undercoat and gloss (2 coats of gloss would be advisable for durability). It’s a matter of preference – both options have their pros and cons. If you want a glossy finish it will have to be oil based though.

For areas exposed to sunlight it’s also advisable to avoid dark colours also.

Hope that helps?

Hi I’m looking to paint some furniture which has a veneer type finish I had some cupboard primer which says is suitable for MDF, melamine etc and was hoping to then use a cupboard paint which is solvent based.

With it being a cheaper type of finish on the furniture would the above paints be suitable? Joy

You should be ok although you may need to give the cupboards 2 or 3 coats of the finishing paint to get a decent result?

These primers that are marketed as suitable for melamine and so on are all well and good but you need to do a lot of preparation. This means washing down and rinsing the surface with sugar soap and then rubbing down with abrasive to remove as much of the gloss as possible.

Aluminium wood primer, oil-based undercoat and oil-based top coats.

Since you didn’t ask your joiner to prime the door you could ask him to fit another door and withhold payment until he does.

Alternatively, you’ll have to give the primer a few days to fully cure and then remove it with fine sandpaper. This isn’t going to be an easy job but it’s the only method that will work.

You’ll need to use a water based or spirit based primer to stop the stain migrating through. Acrylic wood primer works OK.

What was on the wall before? If it was wallpaper did you wash the walls to remove any remaining adhesive?

If the walls are crazed all over you might be better off covering it with lining paper and starting again.

Aluminium wood primer or acrylic primer/undercoat.

An acrylic primer/undercoat should do the trick. You may find the stain still bleeds through but the acrylic will hold it so it doesn’t work through to subsequent coats.

Try a test area first with one coat of acrylic and one coat of your intended finish just to be sure. If you still get the stain coming through you’ll have to use a spirit based primer to block it. It’s very unlikely you’ll need to do this though.

Short answer, yes.

Hi, I’m about to have 2 softwood doors fitted externally to my separate garage & storeroom. Being softwood there’s a lot of knots in them. I am planning to use aluminium wood primer rather than knotting & traditional primer.

However, I have already given these doors 2 coats of clear preservative to add to their protection. Will this affect the performance of the primer in any way? (it soaks in like water).

Also, is it really imperative to knot regular softwood doors, especially as these are never in direct sunlight? Lee

Using a preservative won’t present any problems provided you allow plenty of time for it to fully dry. A couple of days will be fine.

If the doors are not exposed to direct sunlight it’s unlikely you’ll have any problems. If you just used a standard primer you might get some discoloration over time. But an aluminium wood primer should stop that happening.

Yes, of course you can.

You’ll need something to block out the colour so something with more pigment will be better. Regular undercoat or an extra coat of eggshell will do the job.

The problem with wood stain is that it can migrate through to the surface of any subsequent coats causing discoloration. You shouldn’t have a problem with adhesion provided the surfaces have been thoroughly cleaned and abraded.

As a general rule, oil based stains will migrate through an oil based primer and water based stains will migrate through a water based acrylic primer. So to seal the surface you need to use the opposite base primer.

Some stains can be extremely problematic and you may need to use a blocking primer like aluminium wood primer or a spirit based solution like ‘zinsser b-i-n’.

Try a test area first and wait for it to dry before committing yourself.

You are correct, aluminium wood primer will do the trick.

Just to note, aluminium primer does have a high level of volatile organic compounds (VOC’s) – typically 25% – so ensure the room is well ventilated during painting and at least for a few days afterwards.

A solvent based top coat should be fine. If it’s a gloss finish you may find it dries duller than if you’d used an oil based undercoat though.

Yes you can use a water based paint but the undercoat you’ve just applied will need more time to fully cure, hence the problems you’ve encountered. If you can leave it a few days you should be OK.
As a rule use a water based undercoat if you are going to be using a water based gloss – but that’s by the by in this instance.

Yes you can. The only problem with water based paints is they can clog up abrasives when you’re rubbing down so you don’t get as smooth a finish.

I used solvent based Leyland Trade Wood Primer on some pine panel doors which had previously been waxed. Prepared the doors with wire wool dipped in white spirit and thought the solvent based primer would cut through any wax residue – which it did – the primer coat is sound.

However, I tried to cover the primer with a water based acrylic and it is separating and leaving not only brush marks but actual pools with patches of bare primer between. No warning about this on the tin.

Leyland technical department said it should be OK to use a solvent based primer with a water based topcoat and advised me to leave the primer to cure over seven days – which I have – but still have the same problem. I will try rubbing down to provide a key but it will be difficult to get into the mouldings of the panels.

Any ideas please – I know I could use an oil based top coat but I really want to use an eggshell finish which is typically water based. Colin

It’s likely that some wax residue has migrated through to the surface of the primer, which is quite common. You could try wiping down the surface again with white spirit and then cleaning with a sugar soap solution to ensure all the residue has been removed?

You could use a proprietary cleaner/degreaser such as this but the method above will be cheaper and probably just as effective.

If this doesn’t do the trick then you may just have to use an oil based eggshell or satin finish after all.