Ratio of BLO to turps?

[dmede]

The bottom is finally done on my 14' red cedar skiff. I'll be fairing the bottom & sides this week and next weekend will apply a BLO soak to the cedar to go under the paint. This is cleaned & heated BLO from solvent free paint and it has no chemical driers so it should soak in much better than common modern BLO.

I intend to cut it with turps, warm it slightly over a pot of steaming water and soak the boat repeatedly until it can't take anymore, or I run out of BLO.

My question is, what ratio should I cut the BLO to? 50/50? 75 BLO/25 turps?

[Bob Smalser]

This is cleaned & heated BLO from solvent free paint and it has no chemical driers so it should soak in much better than common modern BLO.



Sounds nice, but paint won't stick to it until it dries, and that can take months with raw linseed without heavy metal driers added. I'd surely try it out first, because red lead primer followed by alkyd paint on unoiled cedar works just fine by its lonesome.

Otherwise the turps ratio isn't critical, and often depends on what's left in the cans. 50-50 is typical.

[dmede]

Yeah, I should probably get a test piece going now to see how long it takes to dry.

I expect that it will take a long time to dry, but accroding to the info on the website (http://www.solventfreepaint.com/faq.htm#lead) this is actually boiled LO as oppsed to raw LO. It's cleaned and then heated to help it dry without chemical driers. We'll see.

What I was attempting to do was replicate some of the effect guys like Atkin and Gardner talk about with soaking thier boats in raw LO before painting, but with less drying time. They would soak repeatedly with the oil until the wood no longer absorbed, let it dry, then paint or varnish. I probably won't get anywhere near that much in the wood and will really be using this as a primer.

[Bob Smalser]

I can see an application for Grardner's traditional soak method for unglassed plywood to inhibit checking, and perhaps for boats moored the year round. Although tests show that linseed slows down but doesn't significantly inhibit changes in moisture content. Moor the boat long enough, and the 12% EMC cedar you planked it with will swell to 16%, linseed or no linseed. And unless you add a cup of copper napthanate per gallon, raw linseed can feed mold in warm weather rather than inhibit it.

So for a trailer boat, I suspect all you're doing is adding around 8 pounds a gallon to the weight of the boat. ;)

[dmede]

So for a trailer boat, I suspect all you're doing is adding around 8 pounds a gallon to the weight of the boat. ;)

Hmmm... well maybe I should try it as just a primer instead and not do a full soak? I have red lead, but then I'd be wasting the 2 quarts of the BLO I already bought for this purpose.

[Wayne Jeffers]

Sounds nice, but paint won't stick to it until it dries, and that can take months with raw linseed without heavy metal driers added.

My experience is that you can soak wood with raw linseed oil, wipe off the excess, and paint with oil-based paint (or primer) after 24 hours with no problem. I saw this method recommended by Ken Swan in an article in Boatbuilder magazine years ago as a solution for preventing fir plywood from checking. In my experience, it works well for this purpose.

I suspect the dryers in the oil paint also work their magic on the oil at the surface of the wood, where adhesion occurs. Without wiping off the excess, adhesion may be a problem; I've never tried it without wiping off the excess.

You can add raw linseed oil to oil-based paint to slow drying in hot weather and keep a wet edge while painting. Much the same principle as with the additive Penetrol.

But, like Bob says, I wouldn’t bother with oil on a cedar planked boat.

Wayne

[Canoeyawl]

I have had good luck using a couple of coats of thinned varnish (50% w/ turps) as an under coat-sealer on new construction.
This will prevent the bare wood from leaching the oil out of the bedding and prime coats.

[Thorne]

Dave -

My experience with various mixes of BLO/Turps was not good for the climate here -- the coatings stayed sticky and got stickier when exposed to full 100+ degree sun...aka boating on the Delta.

OOPs, edited to remove my blathering about Le Tonk varnish!
-- Just re-read the main post, and you'll be painting over this mix. Try some test coatings, and expose 'em to lots of heat after they cure to see what happens.

[oakman]

D

I recently used about 15 gallons of the oil you have purchased on the exterior of a restaurant here in NYC. Antique pine stripped and sanded. We used the silent paint remover, six of them to be exact to remove a two part polymer finish the shope mistakenly used on the pine. We then warmed the oil into the finish with the infared paint stripper. soaked, warmed, soaked again till it would not take any more.

Opened in late Feb 2007 and the wood still looks good today. It will need a refresher coat before the winter but I believe it will be a very low maint. finish. With warming I would say you should leave it a week at the least before attempting to overcoat. Test. You can tell how dry the oil is by sanding a little. It will never powder like varnish but you can sand it when dry.

oak