Re: How much epoxy?
Well, us old guys need our sleep, so I don't read this board after about 7pm usually
Roughly speaking, you want to have enough epoxy to form fillets, which help the glass make the transition through right angles at the base of the stringers, and enough to tab the glass to the hull then coat the glass, plus some allowance for waste.
A layup schedule for the stringers that's plenty strong for a 16-22 footer would be (assuming epoxy): 2 layers of 1708 glass tabbing and 1 layer of 1708 to cover the entire stringer and tabs.
Figure 13 or so feet linear (3 yards) of actual stringer, times 2 stringers, or about 12 yard x 50 inch wide cloth for the 2 layers of tabs (assuming you cut the fabric in half for tabs and use half each side), then another yard per linear yard of stringer (6 yards) to cover them overall. Total 18 yards of 1708 cloth. We'll add two yards extra for mis-cuts and waste to come out at 20 yards of 50 inch cloth.
Epoxy needed is about 1.3 times the weight of the glass used for hand layup for a beginner, assuming you don't have massive waste and also assuming you use some for fillets. 1708 weighs about 25 oz. per square yard. 20 yards x25 ounces is 500 ounces. Times 1.3 is 650 oz. or about 40 lbs. Epoxy is about 10 lbs per gallon, so about 4 gallons of epoxy for 20 yards of 1708 cloth with fillets.
Keep in mind these are very conservative numbers. You could buy half the epoxy and all the cloth and see how far it gets you, or you could save by buying in bulk. You might be able to get by with much less epoxy if you're careful.. a good hand layup by an experienced person will use about .9 oz epoxy for 1 oz. glass, which would be a whole gallon less.
You can also buy a roll of biaxial "tape" 6 inches wide and tab with that in 2 layers instead... that would save you about 14 yards of 1708 and drop you to 1 gallon of epoxy for the 1708 plus about 1 more for the tape. A 50 yard roll of tape (plenty) should cost about $55 or so.
Bottom line I'd say get the 20 yards 1708 and 2 gallons of epoxy plus some filler for the epoxy (wood flour or cabosil and milled fiber) to start.
Erik
