Wood is naturally a porous material so it is important that the surface is sealed to ensure that solvents within subsequent coats are not absorbed too readily which will cause premature drying and potential failure of subsequent paint layers. A first coat of primer will also consolidate loose fibres on the wood’s surface which will enable sanding to a smooth finish before applying finishing coats.
There are a range of wood primers available, all with different qualities, and the choice can be confusing.
Water Based Wood Primers
Water based primers are often acrylic based, are more pleasant to use than solvent based alternatives and can perform well if used correctly. The advantages of water based primers are quick drying, good opacity (covering power), low VOC content and brushes can be cleaned with water.
Water based paints can not be used where the risk of rain is imminent and another disadvantage is that these kinds of paint can clog up abrasive paper which makes it difficult to get a really smooth finish. Some water-borne stains can also bleed through the surface of acrylic paints.
Quick Drying Primer/Undercoat is a general purpose acrylic wood primer and combined undercoat suitable for interior use in a range surfaces including softwoods, hardwoods and building boards including plywood.
MDF Primer is an acrylic primer formulated for use on MDF which is typically more porous than regular softwood. It is quick drying and can be used as an undercoat.
Rubol Primer Plus is a premium quality acrylic primer/undercoat for use on exterior timber. You can use regular water based primer outdoors but it’s worth spending a little extra to get the best result.
Oil Based Wood Primers
Solvent or alkyd based primers (commonly known as oil based primers) have been used traditionally to prime new wood. The advantages are that they dry to a hard finish that can be rubbed down to provide a smooth surface.
Oil based primers are compatible with traditional undercoat and gloss paint and will contribute to achieving a high sheen finish. The disadvantages are slow drying times and they can be messy and unpleasant to use.
Aluminium wood primer is an oil based primer with a high aluminium pigment content. Used for some hard woods which contain high amounts of resin which discolors traditional wood primer. Can also be used for very knotty timber where the use of patent knotting isn’t practical.
One problem with aluminium wood primer is that the bulk of the pigment will settle in the bottom of the can if left for even moderate periods of time so it’s essential that it is thoroughly stirred before use.
There are some other kinds of specialised wood primers but this covers the basics. The general rule with all types of primer is that thorough preparation will always yield good results and when selecting a primer for the job you should always use the best quality primer you can afford.
Steve
Great resource, NEW unpainted door frames, where the walls will be plastered after the new door frames installed… I had used water based primers, but, the frames swell, and distort when the plaster is applied… Would oil based primers stop/significantly reduce this issue. Thanks in advance
Darren
Yes, an oil based primer will mitigate the problem. Two coats are better than one also, especially the end grains which are very absorbent.
Mary
I have coated part of an outside shed with aluminium primer, which was recommended to me. On reading this forum it seems I’d have been better going with water based paints. I want a brown finish eventually, not necessarily gloss. Should I switch to water base. Do I still need an oil base undercoat.
Darren
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.
Aidan
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.
Darren
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.
Emma
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!!
Darren
Hi 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 discolouration.
Sally
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?
Darren
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.
DavidG
Can I just ask you to confirm it is ok to use a water based primer or undercoat when the top coat I intend to use is oil based ( I have both already) .if it is ok – it’s exterior garage doors – are there any additional steps I should take – have already sanded bare wood ( pine)
Darren
Yes, generally speaking.
Susan McLaughlin
Hi.
I vanished red pine in my bathroom (water based varnish) 8 years ago. Now wanting to gloss. Do I need to use knotting solution. Primer. Undercoat and top coat?
Darren
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.
Matt B
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?
Darren
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.
Matt B
Brilliant, thanks
Pariera
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
Darren
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.
Tansy
I have a very dark brown front door, think it is wood stain, and I want to end up with pale blue. I will use a primer and undercoat followed by 2 coats of eggshell. Would you put on an aluminium oil based wood primer initially, so the stain doesn’t come through?
Darren
Yes.
Mark
I’m new to painting and need to paint a plywood bath panel am I right in using a wood primer and can then use an eggshell white paint ?
What would be the best primer/paint combo to use ?
Thanks
Darren
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.
Sarah
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.
Darren
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.
Anthony
What are the best primer/undercoat and top coat to decorate new joinery made Sapele doors and windows externally? Acrylic or solvent-based?
Darren
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.
andy peverley
wanting to paint over tongue and groove that’s been varnished without having to rub down
Darren
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.
bill
What type of topcoat paint do I need to cover Acrylic primer on wood. Can I paint over with oil based or solvent based top coats?
Darren
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
Anonymous
Soft wood exterior door new wood primer or undercoat
Darren
So what’s the question?
Nick
I’m importing some timber from China and it says that it will be primed with gesso paint what’s the best paint to spray on to achieve a final colour.
Darren
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.
Rob
Can I use water base primer undercoat then cover with oil based satinwood finish successfully?
Darren
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?
Steve
Hi it says do not stir my paint but when opened it had an oily layer on top ,what should I do
Darren
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.
Liz Warburton-Smith
I have just found an old tin of Dulux primer in the shed. I am planning on painting a wooden window. Could I use it, if I give it a good stir or does primer go off? Also, If a tin of paint has been opened and re-sealed, how long does it last generally?
Darren
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.
Stuart
Hi, all of my window boards are painted / varnished brown. I am having new windows installed. And wish to paint window boards white satin. What is the best prep- lightly sand or completely remove. And which is the better primer to use – Aluminum or normal primer.
Darren
You would need to remove the stained varnish and use an aluminium wood primer.
Anonymous
do I need to remove all of the varnish to bare wood or just a light sanding. Then prime
Darren
Ideally, remove all the varnish back to bare wood.
Raj
Hello, ive 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 seperate 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.
Darren
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?
Robert
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?
Darren
No problems, as such, but to get a uniform finish ensure all the woodwork gets a full coat of oil based undercoat first.
Maggie Roderick
I have undercoated my window frames with Dulux oil based undercoat but the water based satinwood top coat is beading. How can I put this right? Should I put a sealer on the undercoat before using the top coat or will sanding it down help the top coat to adhere?
Darren
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.
Anonymous
Can you stain over acrylic primer.
Darren
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?
Cks
Well put Darren dulux trade with primer and two undercoat and gloss will last year’s. I have done many sash windows this way in high rise Georgian buildings. Pitty the gloss is so thin now though….
John Webber
Can oil based gloss paint be put on water based primer undercoat?
Darren
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.
Caroline
Hi I hope you can help. I’m a decorator and rennovating 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 zinser coverstain for exterior work as another recommendation for going ontop 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 rennovation 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.
Darren
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?
Caroline
Hi Darren, thank you so much for your reply. I had a chance to talk to the carpenter again today. He confirmed that the resinous wood is infact some kind of pine which does infact take paint quite well even though it’s resinous when heated, he asked me if it smelt good when I heated it, which it did … lovely smell!…. He also confirmed that all the upridghts are infact softwood even though they do look like oak, they’re not oak. So I now have softwood everywhere apart from a few old sills which is a huge relief. He also said that he meant Red Oxide primer and not aluminium primer. He used this primer successfully on houses where paint just would not last and told me that the red oxide primer is still okay after 3 years now, which for those windows was a huge success. Three years isn’t very long ! I was hoping my work would last my usual 8 to 15 years once I’ve finished. Do you have any views on using red oxide primer on all the bare wood? I have noticed a layer of orangey red paint has been applied as a primer on some of these windows too at some point when I was burning it off. I just researched it and it says it’s for metal. So in conclusion I am now thinking of avoiding the preservative primer on the few resinous pine uprights and the few old oak sills to avoid the problem you mentioned of activating the resin but definitely using the weathershield preservative primer everywhere else so I am using the complete weathershield system wherever possible. Then going on with another primer on all the bare wood, either the aluminium one or red oxide one and then the undercoat and topcoat. I’m relieved you say I should be able to cover the aluminium primer with 2 undercoats and 2 topcoats. I am assuming it is okay to use the primer I finally choose on the softwood as well as the hardwood and resinous wood and I’m assuming that it should add to the longevity of the paintwork. Dulux HQ said to only bother with aluminium wood prmer on hard wood but It seems logical that it would help with longevity if I’m standing there with a brush in my hand dong the sills ! Very long winded questions. I’m just scared of doing the wrong procedure on so many windows after so much expensive preparation. So in short my question is would you advise red oxide primer or aluminium primer and is it okay to put ontop of weathershield preservative primer and to put it everywhere there is bare wood whether it’s soft or hardwood. Thank you again. Great advice on this site.
Darren
You can use aluminium wood primer on soft wood too. Red oxide is a bit of a favourite with ‘old-school’ joiners but there is no benefit in using it, particularly on modern day softwood timber which often has a high moisture content. Back in the day, wood was a lot more durable than it is today because it was properly seasoned before use. So, really, it didn’t really matter so much what you used as a primer and red-oxide probably worked well because it has a high solid content?
With the benefit of all this further information I think you may be better off using aluminium wood primer on the old ‘oak-like’ timber because you shouldn’t have a problem with moisture content but you may still have a problem with the resin content. I wouldn’t use a preservative on these areas since they have lasted this long without it you’re not gaining anything?
For the new work, which I gather is isolated to the window sills, I would use the Weathershield preservative primer as originally intended. If there are any significant knots or resiny patches you can spot treat these with standard knotting solution. You can then use the Weathershield undercoat to even out everything, maybe using 3 coats on the sills and 2 coats everywhere else?
How long this is going to last I wouldn’t like to speculate but it’s unlikely to be the 8 – 15 years you’re hoping for?
As a caveat, I will add, that this is based purely on my understanding of the situation as you describe it so you will have to use your own judgement to a certain extent.
SudhaThomas
Hi , I am a beginner. I have bought solvent wood primer. The instruction says use 20% by volume thinner if painting by brush. Can I use Turpentine as thinner?
Thanks
Darren
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.
Agata
maybe a silly question but i can’t find the answer anywhere. are there water based paints for wood? i bought the water based primer and don’t know what kind of paint can be used on top… thanks in advance
Darren
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.
Malcolm
Just started renovating our new home.
I’m finding it difficult to get the under coat to adhere to the old gloss paint. I have been informed that the gloss maybe used in the shop fitting trade.
Can you help with some type of etching primer.
Darren
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.
See this earlier post for further info…
Dexter
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?
Darren
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.
Dexter
Thank you Darren. If I were to ‘bin’ the water based top coat, could I use linseed oil paint as a top coat? Should I use oil based under coat over the aluminium primer? Is the aluminium primer even necessary?
Darren
It might be easier to revert to an oil-base finish yes; and yes, you should use an oil based undercoat over aluminium primer. I can’t say whether it was necessary to use aluminium primer or not although, with rough sawn timber, the likelihood of staining was probably quite high, so you were not entirely wrong. I would have tried a trial area first with the water based system to see what happened; but we are where we are.
Melina
Can I apply varnish over water-based primer and paint?
Darren
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.
saritaday68
Hi can I use a water based garden paint over an oil based primer? Many thanks
Darren
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.
Rachael
I have a cellulose based topcoat which needs to go over aluminium primer. Any idea what I can put inbetween to make the two paints bond?
Darren
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.
Stewart Jamieson
Is sanding and aluminium primer the best approach for starting to paint exterior wood that has previously been weatherproofed with linseed oil and beeswax, please?
Darren
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.
Terry
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.
Darren
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:
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
Terry
Thanks for your comprehensive reply. I did not leave the 123 much over 2 hours before topcoating, so had wondered if that had caused my problem. Remember reading somewhere that 123 cures for days after application, but had assumed it would continue to do that even after it had been overpainted.
Debbie
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 ?
Thankyou
Darren
Zinsser is one of the better priers 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.
Mart hudson
Ive used a water based wood preservative on my gates and they have swelled. Ive been told should have used an oil based one. Can this be applied after ive used a water based preservative already? Or should inuse some sort of sealer to prevent the wood swelling anymore??
Darren
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.
Linda Parker
I have new MDF wardrobe. Can I just use one coat of sealant/varnish on the inside and then paint the doors inside and out with primer and paint? The shelves inside will be full of clothes etc. so I just want to protect them.
Darren
Sure, but I would suggest giving the paint a few days to fully cure (longer if you can?) before using the wardrobe to store clothes.
Edina Raboczi
Do you think the oil based primer is a good choice for my cupboards which has a glossy surface now. I wish to paint with some kinda matt or chalky paint?
Darren
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
Anonymous
I use a acrylic primer and undercoat on wooden table and then painted over with water based chalk paint . the paint has peeled off like plastic strips ???? what did I do wrong.?
Darren
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?
peter
What water based clear sealant should I use for unfinished Vaneer doors?
Darren
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.
Pat
I have a plywood desk that i made for a sound booth. I purchased it with one side aanded 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 woodnposts ao how would i do those as well?
Darren
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.
Sorry, I don’t know what you mean by PT legs?
david till
I want to paint over a natural pine door that I previously covered with clear polyurethane varnish many years ago. Can I use a water based primer/undercoat over the varnish before glossing?
Darren
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.
Nigel
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!)
Darren
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.
Ralph
I want to use water based ‘low maintenance’ paint on my new doors and windows but the joiner has already primed them with aluminium primer. Any tips or comments?
Darren
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.
Michael Stewart
I have used OSB boards inside my allotment ahed walls, what paint would you recommend?
Darren
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.
Michael Stewart
Thanks for your advice. Going to use oil base primer and two coats of masonry paint on both sides and edges.
Suzie
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?
Darren
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.
Suzie
Thanks Darren,
I had read on one site that I could use watered down emulsion, like one would use on new plaster to prime it, but I thought on hardboard it would make it soggy and ripple. So I’ll just use a cheap emulsion as it comes then.
Maybe I could fill the joints with wood filler like I am filling the nail holes, as it will sand flat with a fine sandpaper.
Darren
Filling the joints will help but you’ll still get movement. However, for a small area you might get away with it?