Fiberglass tank...

I have a bit of experience with fiberglass gas tanks on boats. If the tank is made from polyester resin, (aka common bondo or other brand maple syrup color resins), the alcohol in the gasoline will eventually cause the tank to fail.

New "fiberglass" gas tanks used for gas with up to 10% alcohol are made from epoxy resin. If the tank is epoxy resin (usually clear or slightly yellow) then it will hold up to the alcohol in gasoline.

There are practically no marine gas tanks made from fiberglass anymore. They are all rotomolded plastic, or welded aluminum plate. The only sure fire protection from leaching plastic resin into your carburetor, and destroying the tank with alcohol fuels.

My guess is it is a common polyester resin tank. Lining it with one of motorcycle products meant to seal rust inside of a rusty tank would probably make it safe for todays gasoline.

JMHO.

Mark

Good stuff here. Caswell Inc. - Epoxy Gas Tank Sealer
Much more durable than the commonly found Kreem brand tank liner

I bought a Paughco Porkster tank off of eBay. The ad proudly said it had been treated with Kreem. When it arrived you could tell that after the Kreem was used the tank had never been opened. I wanted to feel the lineing so I stuck my finger inside and felt around...the Kreem was lifting off the steel in big patches. I contacted the seller, he wanted me to send the tank back for a refund. I said no, I wasn't going to pay $20 to get back $60 which would have ment I would be shelling out $40 to get back $40.

I put 20 feet of towchain into the tank and shook the tank for 10 minutes knocking off the loose Kreem. With the oil mix a tank wont rust anyway.

I just can't recommend Kreem after THAT experience

What if a tank had a thin inner aluminum liner surrounded then by the epoxy resin?- you'd still have the lightweight aspect and ease of molding different shapes, but the aluminum would actually keep the gas off the fiberglass.

What then about those plastic gas cans we all have for our lawn mower gas and in our car trunks? They used to always be tin, now they are usually plastic.

I've had some for quite some time and haven't noticed anything wrong with them, Are they clogging the lawn mower carbs of America?

I'd probably keep some gas in one now for the bike, but I've got a gas station a block away.

Hello out there,
I'm just starting out attempting to build a glass tank and found that fiberglass insulation boards from a hardware store are a b*tch to cut. I built an electric cutter yesterday and finished it up late in the evening. Looks great BUT dosen't work. Trouble shooting tonight.