> Thanks Mike & Paul,

> What's about polyester resin? I can have it here in Ottawa at
> "Canadian Tire" for 53Can$ per gallon. The name of the resin is
> "Bondo marine resin".

> Mike, How is your Walrus plywood project doing? After reading Paul's
> posting to you, I am seriously considering to use the technique for my
> second Kayak.

> Ben B.

I has been years since I played with polyester, but I understand that it is too thick to effectively soak into the wood. I have never seen it recommended as a wood sealant.

However, it has been used for decades as a covering for wood boats. Usually it has been reinforced with glass cloth when used this way. Although you could fiberglass the stringers and frame parts on your boat -- making them much stronger -- I doubt you want to get into such an involved effort.

On small boats which are frequently removed from the water the service life is excellent. This resin is also resistant to deterioration from UV light.

However, if the boat is constantly immersed, water vapor will eventually penetrate the polyester layer, and the wood might eventually rot, or the water vapr may condensed under the layer of resin and cause a delamination. This may take a very long time, if it happens at all! But with epoxy it doesn't happen.

Fiberglass boats (and auto parts) are usually built with polyester resin. I think the product you are looking at is designed for repairs of those kinds of boats. Some verisions of polyester resin are also used as a base for very durable paints.

You don't need a gallon to paint a kayak frame. You could get by with a pint for one coat, and a quart would be enough for 2 or three coats. Surely you can find a smaller quantity of epoxy for half the price of that polyester.

The question here is: do you want to paint the wood, with a product that will sit on the surface of the wood and provide many years of protection, or do you want to seal the wood with a product that will soak into the wood and provide a barrier in that manner? Personally if I was going to paint these parts I'd want a sealer underneath it first, as a primer. If I was not going to paint them, then I would want to at least seal them. If I wanted something that was cheap and not interested in durability I wouldn't bother with paint or sealer. I'd just keep it dry between uses and plan on replacing some parts in a few years.

If the epoxy is too hard to come by, then a thinned linseed oil mix will soak in and (slowly) dry to form a good sealer. The recipe suggested by George Putz should be fine.

Hope this helps.

Paul G. Jacobson