linseed oil for old wood

[m beezo]

I seem to remember that years ago I worked with a guy who insisted on coating old dried out wood with a coat or two of linseed oil before he would paint it. This was especially true on wood that had been striped down to the original wood but even after sanding and cleaning the wood was still a bit gray in color. He thought that the linseed oil made for a better coat of paint and that it held up better. I know that was at least 15 years ago and the primers have gotten better but was wondering if anyone knows about this as a proven procedure or is it a urban legend? We are currently stripping some 100 year old fir boards, 20 ft long 12 inches wide full one inch material. Only one or two small knots in each board. After we strip and sand we are supposed to fill cracks and nails heads and prime and paint. Just want to get it done so it lasts another 100 years.

Any thoughts on this procedure? My local paint supply house did not really have any good answers other than "we do sell linseed oil but do not really know what it gets used for." This from one of the younger guys since the other guys with seniority had the day off for the 4th.

[Victorian John]

Re: linseed oil for old wood

m beezo,

I've always used linseed oil to "rejuvinate" old wood. Sometimes a clapboard siding would be so bleached out that before we would paint it, we'd give it a coat of oil thinned with turps to get some life back into the wood.

On old porch posts, after stripping and sanding, one coat of oil thinned maybe 20% then dried, then primed, then puddy and fill, then spot prime and finish coat. Again, this is my tequnique for old DRIED OUT wood.

Caution, if you use two coats of oil, you might get a skin that the primer won't stick to. The idea is for the oil to penetrate and not build up.

In the 70's pentachlorophenol replaced this practice as gov't study showed six times better penetration than oil, and no skin. Penta has since been taken off the market as you know.

If the old fir boards have a lot of life in them (cut a piece and smell the wood) then probably an alkyd primer would be good enough.

I still oil my gardening tools, wood and metal parts, about every 5 years or so. I still think it's the best and not toxic.

Hope this helps.

John

[m beezo]

Re: linseed oil for old wood

John,
Thanks for the advice. I knew about getting too much on the wood and getting a shine that would not really take paint vey well. I recall when we cut the wood there was almost no smell left in the wood other than the smell of dirt and coal dust. What a messy job this is. I have thinned some linseed oil and have paintd the posts with it which just soaked it up. Almost no runoff or drips as it soaked in almost as fast as we put it on. We are going to just put one coat on since the primer is a linseed based primer also. Somthing from Ben Moore called a penetrating primer.

[Dick Seibert]

Re: linseed oil for old wood

John:

A friend took these pictures at his chalet in Switzerland, I asked him how they kept the wood looking so good, but all he knew was that they oiled it. Do you know what the use?

[Victorian John]

Re: linseed oil for old wood

m beezo,

"Somthing from Ben Moore called a penetrating primer"

For years I added Penetrol to my oil primers. This BM product is just that. And I'll still add some Penetrol to BM penetrating primer if the wood is really dead. Again, I only work on old houses here in the Boston area.

Sounds like you have the right approach to this job. Good luck.

John

[Victorian John]

Re: linseed oil for old wood

Hi Dick,

Nice pics. Finishing oils is a whole different ballgame in which many here are far moe knowedgable than I.

Here's a tid bit for the young guys. What's the difference between bolied linseed oil and raw oil ? Raw oil was used on all exterior applications esp. making paint because the premium cost of boiled oil wasn't justified. Today they price them the same so buy the boiled, more refined, oil.

fwiw.

John

[Jeff B]

Re: linseed oil for old wood

Linseed Oil is boiled to make it dry faster...

Linseed Oil:

Uses: Linseed oil was reviewed as a wood preservative, sealer, polish, wax, and finish. It is used as an alternative to solvent-based products designed for the same uses.

Summary: Linseed oil's efficacy as a wood preservative and sealer is fairly well documented in the scientific literature, although it does take several days to dry. Linseed is available in two forms: raw and boiled. Boiled linseed, commonly used because it dries faster, is not a good pollution prevention alternative due to the potential toxicity of the solvents, metals and fungicides that are usually added to it. As a result, consumers should be advised to use raw linseed oil and to avoid boiled or thermalyzed forms. Gloves should be worn to avoid skin irritation. Linseed soaked rags present a flammability hazard and may spontaneously combust; therefore they should be placed outside to dry, cleaned after use, or placed in an airtight container.

Efficacy: Linseed oil is a common ingredient in paints and varnishes and can be used alone as a wood finish and preservative. When compared to thicker coatings, linseed oil shows improved penetration into wood. Raw linseed oil can take up to three weeks to dry. Additives in boiled linseed oil decrease its drying time to 16 hours.

Environmental: No existing information was found on the environmental effects.

Health: Raw linseed oil is practically non-toxic. It has historically been used as a laxative. It is well absorbed through biological membranes such as the stomach and skin. Linseed oil is moderately irritating to the skin and is known to contain potent allergens. Cautions against the use of boiled linseed oil are common in health literature due to toxicological concerns about its additives. Thermopolymerized linseed oil may be toxic to the liver.

[phillip]

Re: linseed oil for old wood

mix it 50/50 with turps
let dry a few days
then prime with a good oil base paint