Re: Gas tank shroud
This was the way to make small fuel tanks for experimental aircraft and the epoxy resin could withstand the gasoline, but I really can't recommend direct gasoline contact anymore since all the gas we get now has alcohol in it and will degrade the resin probably within about 6 months. The solution would be to line the inside of the tank with an alcohol resistant tank sealer before using if you decide to just make a whole tank in faovr of just making a cooler looking shroud. Also if you plan on making a fiberglass tank, it can be done with the epoxy resin from West Systems but you'll want to make it 6 to 8 layers thick for durability, and of course, use a tank liner like Red Coat to protect the resin from the alcohol. The epoxy resin also remains flexable to a certain extent so it's a lot safer than using poly resins that can crack and form small leaks.
I repaired a carbon fiber tank for a customer about 4 years ago where the fuel attacked the resin and although it held it's shape, there were areas where the resin was completely gone. I had to re wet the cloth with epoxy resin and use a special tank liner to prevent the fuel from attacking it again. Originally the guy just thought his paint was bubbling until I cut thru a bubble to show him it was leaking right thru the carbon fiber.
If you do decide to make a fiberglass tank, be sure to line it with something that's been confirmed to be alcohol proof or it wont last, but to re shape an existing tank it'll work just fine.