There are good reasons for doing it either way. I think applying a sealer coat lets you be a little less careful during the glassing stage. It reduces (but does not eliminate) problems due to outgassing and starving of the glass. One is due to air being expelled from the strips, the other is due to the strips absorbing resin. If you apply a seal coat during rising temperatures you may get some bubbling, these bubbles are pretty easy to remove, but you do need to remove them.

Skipping the seal coat is quicker and eliminates the chances of a poor bond between epoxy coats. You want to apply the epoxy during falling temperatures to eliminate outgassing and you need to come back an hour after applying the resin to look for starved glass. This is not a big deal because you really should do this even with the seal coat.

Epoxy applied without a seal coat will result in more epoxy being absorbed by the wood. This will cause a slightly heavier boat, but since epoxy absorbed deep the wood creates a strong bond there is a slight strength gain. The resin absorbed into the wood also reduces the permeability of the wood to water.

Personally I find the time saved in avoiding the seal coat worth the extra 10 minutes I need to make sure the glass is not starved. I am not concerned about the minimal extra weight from fully absobed epoxy vs. partially absorbed. I have never had problems in a completed boat which I could attribute to lack of a seal, but I have had problems I could attribute to the seal coat.

If you are applying veneer using epoxy, I suggest a seal coat over the whole boat before applying the veneer because you can get discoloration around the veneer due to un-even absorbtion of resin.

Bottom line: If you must work in rising temperatures, a seal coat is probably a good idea. If you just want to be more careful and don't mind an extra day of work, a seal coat is not a bad way to go. If your schedule will not permit you to get back to apply the glass within a couple of days of the seal coat, eliminating the seal coat will work fine. It saves time to skip the seal coat, and there is little risk of screwing up the job without it.

> Greetings. I've reached the point where I'm ready to start applying epoxy.
> I've read that I should use a sealer coat before laying glass down - true?
> Why wouldn't the epoxy penatrate the glass to perform as a sealer if I did
> it in one step? Any comments would be most appreciated!