I agree on the first part, but my preference is to have it welded.

gyrobob wrote:

How about crafting the pieces so they fit very precisely, etching the
aluminum immediately prior to applying T-88 epoxy, using lots of
rivets, and then as a final step -- sealing it all with gas tank
sealer that coats the inside of the tank?

Richard Lamb wrote One fellow told me about the
way he built a gas tank. Formed endplates and a wrapper - all about
.040 5052-H32. Then etched and assembled with PL-1 (polyurethane
construction adhesive) and a few pop rivets. Flanges faced out, btw.
He said it worked well, had so many hours on it. But I never had the
guts to try it.