How breathable is linseed oil paint really?

[Zebra]

I am washing my windows ready for the onset of daily condensation wiping. (They're three years old, softwood, painted with Holkams Linseed Oil paint.)
I notice that there are some small cracks in the paint, particularly around timber joints or where it meets the glass. There is also slight damage in places. If water gets into the wood through these tiny cracks, will it really evaporate away again effectively? Is the paint really that breathable? Or should I be rushing to put another coat of paint on?

 

[88v8]

Rather than paint at this stage, you could use some Capt Tolley.
http://www.amazon.co.uk/Captain-Tolleys-Creeping-Crack-sealer/dp/B003T6EJ9A
other retailers are available

If you want to see how long before the paint starts to lift off the soggy wood, you might leave one window untreated

Ivor

 

[plasticpigeon]

I really don't know the answer to your question, but I do wonder how important it is for paint to be "breathable", in fact I'm not sure I even know what it means!!!! I think the most important quality for paint that is going on wood to have is flexibility, to be able to cope with some natural movement, and as I would want it to keep water out of the wood, I wouldn't want it to be able to transport liquid water. Personally I think if the paint is cracking it is not a bad idea to put on another coat, but the most important thing is to make sure there is nowhere for water to get trapped under the paint (as happens with modern plastic paint when it peels, which I think may not happen with linseed, so you probably don't need to be in such a rush to fix things!).

 

[malcolm]

It is very important for paints to be breathable - you get movement and cracks that let water in, and the only way the water can get out is through breathable paint. Empirical evidence around here suggests the paint was breathable enough to keep the timber going (despite lack of maintenance) right up until they invented waterproof paint . I would be tempted to smear some linseed putty over the gaps if they are big enough.

 

[skier-hughes]

Maybe a coat of linseed oil as suggested by Holkams?

 

[Zebra]

Hmm, that's not a bad idea skier-hughes, certainly easy to do and couldn't hurt. Is it supposed to be boiled or raw, can you remember?

 

[wobs]

Hmm, that's not a bad idea skier-hughes, certainly easy to do and couldn't hurt. Is it supposed to be boiled or raw, can you remember?

Holkams (now Allback) reccomend raw linseed oil, while LinseedPaintCompany recommend boiled. This is down to the way they differ in their recipe. LPC add tree resin etc. (going from memory).

Edit: This says boiled for the maintenance coat of Allback:
http://www.solventfreepaint.com/i/PDF/AllbackLinseedProductBrochure.pdf

 

[formerly known as]

holkham stated raw as a primer - not sure how RLO might work over the holkham paint ..... best try a test first. However, on one of my oldest windows, I periodically use RLO over the historic paint and that does well.

 

[88v8]

....on one of my oldest windows, I periodically use RLO over the historic paint and that does well.

Is this effective on external paintwork?

Ivor

 

[plasticpigeon]

I oiled my painted slate fireplace with linseed oil. That was a silly thing to do. It looked fine but it takes a long time to dry or oxidise or whatever it does, dust sticks to it, and fingerprints can still be left in it a couple of months later. When I get the time I will take it off with wax and polish remover. As traditional paint had some driers in it, perhaps a mix of oil and driers would work as the oil would dry more quickly. However after all I have read about linseed paint, it sounds like applying it is a form of torture to me!

 

[skier-hughes]

....on one of my oldest windows, I periodically use RLO over the historic paint and that does well.

Is this effective on external paintwork?

Ivor

According to Holkhams, after 7 years give it a coat of Linseed, then the next 7 years give it a coat of paint, repeat.

Appears to work quite well at our house.