> What is the LATEST on this hot topic. I'm almost ready to start glassing
> my Expedition. Do I precoat the wood or wetout glass over bare wood. There
> seems to be good arguments for both methods. On earlier boats, I precoated
> with no problems. I find it interesting the on again, off again of this
> subject. It seems those that used to precoat, now don't and those that
> didn't, now do. Throughly confused!!

> Larry C.

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Pre-Coat?

Usually I don't, as the adhesion never seems to be as good, when there's a layer of previously applied bare resin on the surface. Also, unless it has completely cured, the stickiness will interfere with laying the cloth out perfectly straight and undistorted.

However, if I'm using a porous, non-resinous wood such as Sitka Spruce, which will suck the epoxy or vinylester up and cause a dry undercloth condition, I may do the following: I mix up small amounts of resin in a cool room---about 55-60 degrees F and rub it into the wood by hand, going over and over each spot. I use a small hairdryer on low-heat and melt the resin down into the wood, as I go. I use a minimum of resin and when finished, there's none left on the surface. The heat helps it penetrate and cure. I then leave it overnight in a warm room. Before applying the cloth, I very lightly sand it with 400# silicon-carbide paper. The wood has been penetrated more deeply and strengthed better than it would have by just brushing the main resin coat on at room temperature. You could expect bad things to happen, if you used a heat gun on the main layer of cloth and resin, but by using just a little resin on the bare wood and working it completely in, before going to the next spot, these problems are avoided. Most people would choose to use thin gloves when touching the resin.

I always use this heat-assisted pre-coat rub-in on wooden paddle blades. When I use mahogany veneer, I lightly boil the raw sheets in a small metal barrel for an hour, to remove the natural resins. This opens up the pores and allows the epoxy to penetrate much more deeply and also reduces any chemical incompatibility between it and the wood. I dry the veneer in a rack that holds it flat, to prevent curling. The result is greatly increased strength and life-expectancy in the paddle. Yesterday, I used a wood paddle I made in this way, 22 years ago. It seemed as sound and functional as ever. I wish I would have held up as well, over that time. However, the boiling will make the veneer more brittle and care must be taken not to split or break it, during the paddlemaking process.

Steve McDonald