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Hardening wood

Hardening wood (post #169694)

jyang949 on Tue, 01/31/2012 - 09:50 (updated 01/31/12 - 01:42)

General Discussion

A recent issue of Old House Journal recommended applying a 50/50 mix of linseed oil and turpentine, as much as the wood could absorb, before painting trim, doors, and around windows. It's supposed to harden the wood and make the paint last longer.

I've never heard of this practice. Is it worth the effort?

Janet

exterior prep (post #169694, reply #1 of 5)

by RalphBarker in reply to jyang949 [original] on Tue, 01/31/2012 - 10:24

I haven't heard of that practice, either, Janet. But, I would think that it might also depend on what type of paint one is using, and whether there is a time lapse between prep and painting. I'm not sure that water-based paint would like the linseed oil, and there's a question of whether the linseed oil might need some time to cure.

Dewaxed shellac is also good as a sealer for new wood. It dries very quickly, and can be used under almost any finish.

I am not a "finishing expert" though. You might want to post your question in the Finishing section to get expert advice.

Janet, I don't think it (post #169694, reply #2 of 5)

by joinerswork in reply to jyang949 [original] on Tue, 01/31/2012 - 15:48

Janet,

I don't think it will harden the wood. And as Ralph says, it's questionable (to me at least) whether it has any benefits as a primer for latex paint. But I have heard old timers recommend linseed oil and turpentine as a prep for windows before glazing, as a sealer or base coat under putty or glazing compound. Supposed to make it stick better, and/or prevent rot.

Ray

Linseed oil, boiled or (post #169694, reply #3 of 5)

by lwilliams in reply to jyang949 [original] on Tue, 01/31/2012 - 19:31

Linseed oil, boiled or otherwise, supports fungal growth. I once had a job building a number of park benches for our local Parks Commission. I intended to treat the white oak they were made from with a wood preservative that was on the market at that time. It was back-ordered and didn't come in when I needed it and the guy in the paint department of the local lumber yard suggested the boiled linseed/turpentine mix. I used it on the first of two runs of benches. I didn't have enough saw horses to handle so much material and used the handrails on the corners of our porches for finishing/painting that first run. We have wrap around porches on three stories so it offered a lot of extra finishing space. I wasn't worried about getting the oil turpentine mix on the hand rails and was a little sloppy but did wipe it up. The preservative came in by the time the second run of benches was ready for finishing.

Within three years that first run of benches had mostly rotted but the others lasted more than 15 years. The railing on my porches also rotted and I wasn't able to do anything to stop it, though I tried. It turned into a real expensive lesson.

That's baloney. There is no (post #169694, reply #4 of 5)

by HowardAcheson in reply to jyang949 [original] on Wed, 02/01/2012 - 07:59

That's baloney. There is no way of hardening wood except by petrifying. BLO even when fully cured is a soft, flexible material. The turpentine is nothing more than a thinner helping the BLO to be absorbed somewhat deeper into the wood. You can put hard finishes on the wood but you can't make the wood itself harder.

Howie.........

I've read many acounts that (post #169694, reply #5 of 5)

by Quickstep in reply to jyang949 [original] on Wed, 02/01/2012 - 19:49

I've read many acounts that indicate the the oil/turps mix penetrates the surface more than paint alone would and therefore promotes better adhesion of oil based paints. I can't imagine that it would do anything for latex paint other than make it peel. I also can't imagine that this process would promote better adhesion than a high quality primer.