Sorry
Didn't mean to overwhelm, the idea was to give all the pertinent info up-front.
Definitely, treat epoxy with respect, the stuff can cause dermititis for some.
Hey, while I'm at it, there's a pretty good comparison of cured epoxy colors at One Ocean Kayaks. Another good guide is contained within Nick's book, the consumate bible on strip-building kayaks.
Also, some alone without glass of other additions are brittle, others tough. It varies with cure times and cure temps, too. Also, what the mix was (picture the low-man-on-th-totem-pole barely making a living and not really understanding the need for care, mixing the various fractions components together). It's an art, not a science, and so it goes.

: Wow! Overwhelming amounts of information. Very much appreciated though.
: Half the fun of a new hobby for me is in the learning involved.
: Thanks to all for sharing your knowledge and experience.
: I'll go with US Composites.
: Aurel