Soak WRC planks with linseed oil before painting?

[dmede]

In one of John Gardner’s books (can't remember where now) I recall him stating that he would soak his lapstrake planks with boiled linseed oil (I think, maybe with some terps) until it wouldn’t soak up any more then wipe and let it dry a bit before painting.

He said he did this to swell the planks and minimize shrink swell cycles as the boat went in and out of water (since the wood is full of oil I guess it wont take up as much water).

Harry Bryan makes no mention of this type of treatment for his fiddlehead canoe, which I am building. The western red cedar I am using seems really thirsty, it sucks up epoxy and oil like crazy so I am wondering if this type of oil treatment prior to painting would be beneficial or detrimental for my little boat? If it makes any difference I plan to paint with Kirby’s or equivalent on the outside and varnish or Cetol the inside.

Any and all opinions or amusing anecdotes are welcome, thanks,
dave

[Bruce Hooke]

In Walter Simmons' book Finishing he says that the quality of boiled linseed oil has gone down a lot in recent years and so he recommends using raw linseed oil with Japan Drier added so that it will cure. I realize that does not answer your question, but if you do go with oil I thought you might find that information useful. It probably matters more if the final finish is going to be transparent...

[Jay Greer]

Boiled linseed oil thinned with turps is a time honored method of pre-priming wood for paint. The oil becomes a part of the wood and so will prevent moisture intrusion as well as providing a binder for the paint.

The modern choice is to saturate the wood with penetrating epoxy. My mind sits on the fence with this. I know that the oil works; But, the expoxy will too. In the long run, I would choose the lesser of two expenses.
Or as was said in "A Master and Commander, the lesser of two weevels."

[Scott Rosen]

I remember reading somewhere reliable that experiments showed that linseed oil is not waterproof and does not reduce or slow the absorption of water. These experiments also showed that the oil does not penetrate any better than paint or varnish.

It 'works', in that it will provide a base for paint, and used alone it will give some protection to wood. But, as a primer, it doesn't work any better than lots of other stuff you can buy ready-made in a can.

Epoxy, on the other hand, will slow (but not stop) the entry of moisture in AND out of the wood. The thicker the coat, the more it will slow the moisture. Although it will not penetrate very far into new lumber, it will provide a stable coating to use as a base for paint or varnish, and will allow your paint job to last longer, provided its protected from UV light and provided the wood doesn't get wet beyond the fiber saturation point. You can't use it alone as an exterior finish, because it has no UV resistance.

My advice (it's worth what you pay for it), is to prime with CPES then paint and varnish. Kirby's works great with CPES. Varnish does too. I don't know about Cetol.

[dmede]

Im building the Fiddlehead as traditoinal as possible (within limits) so I will not be coating with epoxy. If Harry doesn't need it than presumably neither do I. My assumption about the oil is that it does not need to impede the water, rather it takes the waters place in the wood, swelling it as the wood soaks up the oil. Beacsuse its oil it would not dry out as much and would keep the wood more stable as it went in and out of the water. Does that sound rigth? Its how Gardner explained it anyway.

Scott, I understand that for most wood what your saying makes sense, but the WRC I'm using seems to suck up oil. Ive been dabbing the ends of my screws in some house hold bees wax and orange oil as a lube. Any place where I used a little too much I can see the oil seeping back up to the surface and around the screw hole. Its really amazing how far it seems to migrate. I also tried to fill some scew holes along the garboard/bottom chine with an epoxy and wood flour mix. It was a light mix, like syrup. It filled the holes well and looked like it would just need a dab of sandable filler later on. When I came back after a few hours the WRC had sucked all the epoxy right out of the holes, leaving the wood flour epoxy coated to the screw hole walls.

[ 06-08-2005, 06:44 PM: Message edited by: dmede ]

[Wayne Jeffers]

Dave,

I like linseed oil, in the right place.

It is not waterproof, but it is a basic law of physics that two objects cannot occupy the same space at the same time. Any space you fill with linseed oil will not be available to take up water.

As you've noted, some woods will readily soak up linseed oil. Others will soak up but little.

For an oil finish, boiled oil is best unless you want to wait a very long time for raw oil to dry. Boiled oil has chemical driers added and it will dry before soaking in so far. It will form a surface coating, like a primitive varnish.

If you use raw oil to treat the WRC before painting/varnishing, it will soak in and it does not matter one whit that it will not dry under the topcoat for a long time. (It will not interfere with adhesion of your oil paint.) You can cut the raw oil with terps and/or you can carefully warm it to get better penetration. Give the wood as much as it will soak up, then wipe well to remove any excess left on the surface.

Dispose of the rags carefully, as they can spontaneously combust if left in a pile.

After wiping, wait 24 hours or more then prime/paint with oil based products. You can even use an oil based primer and a latex topcoat.

Wayne

[Don Kurylko]

Wasn’t there a posting awhile back somewhere from a fellow from Sweden or Finland who described the “oiling” process used by Scandinavian boat builders? As I recall, there was something like a total of 60 applications of oil to the hull by the time it was finished. That’s some serious oiling! That ought to hold up in the Florida noon day sun. At least for a couple of months! :eek:

[Bob Smalser]

Soak WRC planks with linseed oil before painting? By all means....as much as it will take for as long a time as you care to do it.

To really speed up drying, for your last coat mix BLO 50-50 with Daly's Teak Oil.

[wyndham]

What Bob says. Roll the boat out into the sun. 50/50 boiled linseed oil and turps. Get a pair of good rubber gloves and a wallpaper paste brush. Slather the stuff on until it won't soak in any longer. Let the sun shine. Slather on some more. Repeat until you're sick of doing it. Flip the boat over and do it again.
A couple bottles of ice cold beer makes the oil soak in better, makes the paint go on smoother....
Keep the stuff off your skin especially in the sunshine. The burns can be very painful.
Never ever ever go to WC without washing your hands first. Trust me.

[Kermit]

I don't think beer is advisable to cut linseed oil. I'd stick with the turps. It IS an effective product for hydration of the painter, and yes, try to keep it off your skin--down the throat is best.

Bob, if this is a canoe, and not likely to live in the water, is water absorbtion even an issue? I'm also curious as to whether absorbing all that oil will make his canoe perceptibly heavier. Could that be an issue in a portage? :confused:

[Bob Smalser]

A gallon weighs 8lbs, and given what evaporates off in the sun, I doubt you'll actually get anywhere near a whole gallon into the wood.

To me, the issue is more longevity than water absorption. As wood ages, it loses some of its lignin, the glue that holds the cellulose together....ever notice how brittle antique wood is? The linseed doesn't prevent that, but it slows it down a lot, keeping the wood subtle. Driers full of heavy-metal salts are enemies to that purpose, however, and probably the best treatment is raw linseed....which is dramatically slower to do.

[dmede]

Great help from all, thanks.

I have a couple questions:

First, should I also soak the iside if I plan to finish it bright? I don't know what coating I will use inside yet and will gladly take reccomendations.

Second, whats the official verdict on raw versus boiled? I want good penetration and since its going under paint/varnish I don't need it to "dry" to any kind of finish so raw sounds better unless its not necessary? If boiled will work just as well and is cheaper or easier to get I'll use it. FYI, my planks are only 5/16" thick and like I said they really drink it up.

dave

[Wayne Jeffers]

If you want it to soak in, you want raw linseed oil.

If you want the oil to be the finished surface coating, boiled oil is a better choice at least for the final coats.

Either should be available at any decent hardware or paint store. Little or no difference in price. Gallon cans are a lot cheaper than buying four quart cans. IIRC, I paid $10 for may last gallon of raw linseed oil.

Remember to be careful with the oily rags. We don't want any fires, eh? ;)

Wayne

[PeterSibley]

Dispose of the rags carefully, as they can spontaneously combust if left in a pile.

I would like to really emphasis this! I came very close to loosing the house 20 years ago, first time I used oil.I had put the rags in the waste bin outside...a couple of hours later the bin and contents were on fire,I'm very glad I had not gone out .These days I put them in a 5 gallon drum at the end if the day and throw in a match.

[Canoeyawl]

Some thoughts on Paint and Oil…
My experience with oil paint and oil based bedding compounds is this; if you apply the paint/bedding directly onto the wood, the oil will leach out into the wood leaving behind a much weakened pigment, sometimes just some “dust” depending on how “thirsty” the wood is! This is not ideal for top coating, what we want is a good initial bond. I prime all bare wood surfaces with varnish thinned with turps at about 50% at least two coats before paint. You can tell if this is enough. This is also standard procedure as prep for any bright work. It has worked well in practice and given my paint jobs longer life and a better bond. For new construction on the home, porch decks, doors and windows etc. that are painted with oil paint I use boiled linseed oil thinned with turps for the same reasons. This also has given me good service. Raw Linseed oil has no place in a boat in my opinion. LOL- Mold and mildew love it.

[Todd Bradshaw]

If I wanted to finish the inside bright, I'd use Deks Olje #1. It's an easy to apply oil finish that soaks in very well, dries pretty quickly, doesn't darken with age and is easy to renew. Costs more than linseed home-brew, but I don't care much for linseed oil and think the Deks has aged much better on the things I've oil finished. I'd probably use it on the whole boat and have used it in the past as a base for paint and varnish, though I don't know whether it's supposed to be used that way under other coatings. I've never been very fond of Deks Olje #2 (their glossy topcoat) but I've never finished anything with #1 that I wasn't extremely happy with.