: When I recieved my epoxy from Raka they included an instruction
: pamphlet on how to epoxy fiberglass the wood.
: It states that doing a precoat of epoxy on the wood then
: laying down the cloth with more resin is the correct procedure.

: Can I get comments on this??

: Julie

If you do a precoat with a very tiny amount of resin -- basically wipe it on and then immediately scrape it off with a plastic squeegee -- then you will have a barrier layer, which will give you good control of the total amount of resin used in wetting out the glass cloth. This helps to keep the boat's weight down, and can reduce the use of epoxy. Theoretically that would reduce costs, too, but in practice you pay for a gallon (or 2) of resin and either use it all, or have a little left over.

If you don't use the precoat then the open pores in the wood will absorb your epoxy when you apply it to wet out the glass. This can be good, or bad -- but since you are not in control, you just hope for good luck. The best scenario would be that your cloth would wet out ompeletely, and then just enough of the excess resin would soak into the wood. In a perfect case your glass cloth would then drop into tight contact with the wood, as there would not be enough resin on the surface to allow the glass cloth to float above the wood.

In any other case you stand the chances of applying too much resin and having the glass float (structurally this is OK, but you add more resin to fill the weave = more weight); or you can apply too little resin and the wood will absorb it, "starving" the cloth. It is very difficult to "rewet" glass cloth, so in extreme cases you redo the glass in a few areas.

Another problem you may encounter if not using a seal coat is "outgassing", which can cause air trapped in the wood to bubble out. This can be induced by heat. Even gentle warmth from the setting of the epoxy can trigger this. Those bubbles can get trapped under the threads of the glass cloth. It is slightly unappealing visually, but usually not a real structural issue. Those "tiny bubbles" have been referred to as the "Don Ho" problem. The usual "cure" is to apply the resin late in the day so that as temperatures drop the wood tends to suck in more resin as the trapped air shrinks.

However you do this, if you have problems you can place the blame on one technique or another. And if you don't have problems,(which is likely going to be the case) you can be certain that whatever tehnique you employed was the correct one.

I'd go for the very light precoat myself. In fact, if I had the time, I'd like to precoat the panels before stitching them together. It could save one or two pounds from the final weight of the boat. With the panels laid flat you could apply an even coating without getting runs. Once the resin had hardened to a "green" state you could scrape the panels smooth with a cabinet scraper, or, in a few days you could sand them to a plastic-like smoothness. Sanding the panels while they are flat would cut down a bit on the time involved in sanding the interior, which is more difficult to sand than the outside of the boat.

Just some thoughts. Good luk with your project.

PGJ