Painting wooden windows

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David321

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#248896 15-Apr-2019 13:49

Hi all,

I am currently painting the exterior of my wooden windows, I am sanding first then applying two coats a Brittish Paints 4 Seasons semi gloss.

On the window I am working on at the moment I had to sand right back to the bare wood in a couple of places, I did not bother priming those bit as the paint claims it is self priming, but a day later I found some paints of the window were seaping a sticky light brown substance, and it was mainly (from memory) where there was bare wood.

I suspected this had to be from not priming those areas and went to the paint department in Mitre10 who also thought the same and they told me to sand it back and prime it with Zinsser Bulls Eye Primer (a water bassed primer) then apply my top coats again.

After asking for a lot of advice etc I relised when I got home I had forgotten one important question, how many coats of primer!?

Are there any paint pro's on here who could recommend if I should do one or two coats of the primer in my situation? The info I have found online says "in some cases two coats may be required", that does not relly help me as I do not know what cases require two coats.

I would prefer to only have to do one coat of course as its less work and less waiting to get the top coats on, but if it will do a better job at stopping the oil seaping threw then ill do two coats.

https://www.mitre10.co.nz/shop/zinsser-bulls-eye-primer-123-3-78-litre-white/p/359819

_David_

tdgeek

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#2217430 15-Apr-2019 13:55

One coat. But as its says, 2 coats may be required, meaning coat 1 has not sealed fully. Put one coat on and wait 24 hours to be sure its sealed. Being outside, and you had seepage, I'd do two anyway

mdf

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#2217432 15-Apr-2019 13:59

What sort of wood? Windows (particularly hinged windows) are often made of cedar. Cedar usually requires an oil based primer. Oil based stains will seem through water based paints, which sounds like it might be the case on your initial coat.

timmmay

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#2217458 15-Apr-2019 14:41

I find it best to sand back to wood if it's not a great surface, prime with a one coat of good brand of oil based primer (Dulux or Resene), two coats of top coat. If you use no more gaps or similar you need to give it 24 hours to dry before you prime or paint over it... found that one out the hard way.

neb

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#2217600 15-Apr-2019 18:13

David321: I did not bother priming those bit as the paint claims it is self priming,

I would always prime exterior paintwork with a primer appropriate to the surface being painted, people keep trying to tell me self-priming paint is getting better all the time but I don't know which of the two it is, better BS or better marketing. Primers and paints serve two totally different purposes, so "self-priming paint" is at best a poor tradeoff, at worst just marketing BS.

neb

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#2217601 15-Apr-2019 18:14

timmmay:
If you use no more gaps or similar you need to give it 24 hours to dry before you prime or paint over it... found that one out the hard way.

Also make sure you're using a paintable sealant, some silicone-based ones can't be painted.

tdgeek

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#2217602 15-Apr-2019 18:19

neb:
timmmay:

If you use no more gaps or similar you need to give it 24 hours to dry before you prime or paint over it... found that one out the hard way.

Also make sure you're using a paintable sealant, some silicone-based ones can't be painted.

You mean like the one I used on a vanity at our last house..... :-(

David321

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#2217603 15-Apr-2019 18:29

I always thought primers should be oil based also but I took the advice of the staff at Mitre10 and took the Zinsser water based primer. After reading about it online it seems it is quite popular and good quality.

I was told by them that a water based primer would be best to stop the oil seeping through the paint, they told me oil stops water and water stops oil which made sense to me.

I'll go with two coats just to be sure as there is not a lot to do anyway.

_David_

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timmmay

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#2217605 15-Apr-2019 18:37

Primer is a specialist product, and what you should use depends on your wood. I have cedar, which is very oily, so you must MUST must use oil based. If you don't paint will bubble or flake off, I had both. Pretty sure whoever did this house last used no primer or the wrong one.

Dulux 1step oil based seems to have been effective. It primes, seals, and undercoats all in one. It bonds to the wood really well and provides a surface for paint to grip to. It's one less thing paint needs to do.

A good friend of mine works for Dulux, so I heard a lot about it.

neb:
David321: I did not bother priming those bit as the paint claims it is self priming,
I would always prime exterior paintwork with a primer appropriate to the surface being painted, people keep trying to tell me self-priming paint is getting better all the time but I don't know which of the two it is, better BS or better marketing. Primers and paints serve two totally different purposes, so "self-priming paint" is at best a poor tradeoff, at worst just marketing BS.

Paint as primer is probably getting better. Might be good enough. Doesn't mean it's the best option.

tdgeek

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#2217611 15-Apr-2019 19:06

David321:

I was told by them that a water based primer would be best to stop the oil seeping through the paint, they told me oil stops water and water stops oil which made sense to me.

That makes sense. I always took it that water based dries quick, so it creates a barrier, literally in minutes. The lengthy drying for solvent based allows time to seep through, and if the problem is also oil based, the primer dissolves it rather than creates a barrier.

timmmay

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#2217617 15-Apr-2019 19:31

David321: I was told by them that a water based primer would be best to stop the oil seeping through the paint, they told me oil stops water and water stops oil which made sense to me.

Based on my experience and advice I've gotten that's completely wrong.

My cedar weatherboards are extremely oily. I had holes drilled in them to have insulation pumped into the walls, they leaked oil / sap for about three months. That's pretty oily.

I used oil based primer on those weatherboards. It lasted a couple of years before bubbling off. I used an oil based sealer on another part of the house, it seems to have stayed on.

So my recommendation is if you have any doubt at all, go for an oil based primer. I've been told it's the best bet, should stick to anything, and cover any marks and stains best.

But don't take my word for it. Call up the Dulux or Resene helplines and ask a professional for good advice. Also Google the type of primer to use on your wood, if you know what it is.

David321

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#2217621 15-Apr-2019 19:55

Also Google the type of primer to use on your wood, if you know what it is.

That's the problem, I don't know what type of wood my windows are Haha. I might hop back top mitre 10 tomorrow and see of I can find another staff member in the paint area and tell my story to them and see if I get the same suggestion.

_David_

timmmay

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#2217622 15-Apr-2019 19:59

Don't go to M10, call the Dulux helpline. They're good. My friend trained half of them.

Like I said - if in doubt, go oil based. Do it once, do it right.

mdf

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#2217977 16-Apr-2019 10:04

timmmay: <snip> So my recommendation is if you have any doubt at all, go for an oil based primer. I've been told it's the best bet, should stick to anything, and cover any marks and stains best. <snip>

Believe it or not, there are a few types of timber where oil based primers won't stick - especially natives like totara and matai. These are most often used for flooring but sometimes - in an absolute crime IMO - weatherboards for older houses. Both are usually quite dark reddy brown colours, though that itself isn't definitive.

http://www.nzwood.co.nz/ is a good resource, with grain pictures for most native timbers.

To the OP, this is what you're looking for to identify cedar:

Might be lighter (or pinker) than this, but that's the general grain pattern.

David321

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#2222278 22-Apr-2019 17:07

Hi all, got an update, I decided to take the advice of the mitre 10 staff as I had already brought the water based primer and figured if it does not work I'll take it back for a refund and get the oil based primer.

I did two coats to be safe and it has now been a few days and there has been no oil come threw the paint, so it must have done the trick!

_David_