Fiberglass fuel proof?

[Lucky]

I've always understood fiberglass to be duel proof when used with non ethanol gas & avoid additives.
Recently ive been working on Spectres tank. (Tiffany's Swiss cheese tank). There is one spot with a dime size hole that keeps springing a pinhole leak. I reglassed it today, a thick layer of resin followed by a layer of fg mat, another layer of resin, another layer of mat & a final layer resin. I let it dry between layers too.

Any other advice? When dry i can see thru it.
Thanks, --Lucky


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[Rick G]

Reports from racers of classic bike , with fiber glass tanks , report that they are dissolved by pump gas. The resin ends up in the carb . Perhaps if you  por 15 it after repair it will be ok.

[fret not]

Lucky, there are different types of resin for making fiberglass lay ups.  We used some called "iso" something or other that is supposed to be fuel proof and also much more heat tolerant than the typical polyester resin.  We got the resin from one of the guys in the Utah salt flats racing organization that has a speed shop in Ogden UT.  We made a fairing, not a fuel tank.

One of the problems here in California was when EPA required fiberglass tanks for gas stations to replace all the rusted out steel tanks, then required MBTE in the gas.  The problem is the stuff bled through the fiberglass tanks.  I think we finally got rid of the MBTE but now have alcohol in the gas.  Alcohol is not good for regular polyester resins and I don't know if the ISO resins will stand up to long term use with fuel containing alcohol but it is better than the regular stuff.

I think Rick is right in sealing the inside so the fuel can't contact the resin.

[Lucky]

K thanks.


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[motoracer8]

 I refinished a rusty old Norton tank for a guy a couple of years ago, when I had it blasted it had many little rust holes in the bottom, rather than cut the bottom out and make a new one, witch I have done, I had it metal sprayed. It's a process body shops use.  So far it has been leak free, keeping my fingers crossed.

  Ken