Tom, I didn't see a formula in CanoeCraft he just ball parks it at 2 gallons. Nicks book The Strip Built Sea kayak had a chart with the following note:

"The amount of epoxy you need depends on the thicknessof the fiberglass you're using and how much resin the wood absorbs. The first coat uses more resin because the wood absorbs it. Subsequent coats just need to wet out the fiberglass. An amount of 150 square feet per gallon translates to about one fluid once per square foot."

Epoxy Usage Estimates

Coverage (sq ft/gallon) Fiberglass first coat Subsequent 4 ounce 150 300 6 ounce 130 250 10 ounce 100 170

Density of mixed epoxy nominally: 8.8lbs/gallon

There now I look like an epoxy expert! Now if you'll excuse me I have another couple weeks of sanding left on my own epoxy! HA HA Travis