I have used the 635/556 epoxy, fillers, and fiberglass from USComposites on three boats so far and I'm very happy with it. It is a slow epoxy...just like they say...but I live in Texas where it's hot. They also say the epoxy is blushless and I have had no problem with any blush. You can see my strip built boat at the link below. Log in as "guest" password "guest" and go to the srchr HV16 album. You can't miss it. The boat is not finished yet...I just started the hatches and cockpit today. I designed the boat using KayakFoundry, by Ross Leidy. I'm going to have to put up some new pictures soon.