Fiberglass gasoline tanks, can they be done "right" ?

Don't go off second hand recommendations.

Each resin supplier offers a list what chemicals each resin is appropriate for. They're easy to find on their websites.

 

I don't doubt you, but VE was less in vogue when I made those tanks a long time ago. I enquired at the time about using epoxy, and the answer was "no". But I understand there are specialist epoxies that do the job very well, and could be used perhaps just to line the inside, this is sometimes done with metal tanks, to beat corrosion, called Novolac epoxy or something similar, resistance to chemicals and solvents is its "thing".

 

The red is the tank. The relief is big enough to fit the moulded cap from the same mould. And the relief is bigger than a skimpy 1/4" bonding area. Just requires a split in the mould at the arrow.

 

Ok thanks will take a look, that ISO DION spec I read through with the supplier and had very detailed ratings. I want to say it was rated for 50% Ethanol concentrations at 100F or something ridiculously out of the intended service parameters. The VE I get from there is not at all capable of the same but poking around I see mention of DION VE's for gasoline.