Gasoline-safe fiberglass resin?

[JackScott]

I’m looking for gasoline-safe fiberglass resin to fix a weeping fuel drain in my right tank. Can anyone recommend a product I can use?

i spoke with Heather and Brandon at Kitfox, they suggested I drill and countersink the existing drain hole, fill it with resin mixed with milled glass fiber, cover it with a few layers of resin and glass cloth, then drill and tap a new drain hole. All I’m missing is the resin to make the repair. Brandon suggested polyester or vinyl-ester resin, but I haven’t found a product yet.

I found Bondo resin at the auto parts store, they even have some with the milled fiber already mixed in. Will that do the job?

Thanks,
Jack

[Delta Whisky]

Good question deserving some research. I found this (which appears interesting): https://theepoxyexperts.com/shop/adhesives/chemical-and-water-resistant/max-gre/max-gre-48oz-epoxy-resin-gasoline-resistant-4-coating-glue-fiberglassing-carbon-fiber/

Other sites I found suggest that a polyester resin is NOT the answer. It'll take a vinyl ester or epoxy resin if not a special chemistry such as the above.

Let us know what you settle on and how well it works for you.

[Rodney]

When fully cured, J-B Weld is completely resistant to water, gasoline, and about every other petroleum product or automotive chemical. For wet-surface or submerged water or gasoline repairs, try our SteelStik or WaterWeld. ... KwikWeld is a great alternative to original J-B Weld when you need a quick-setting epoxy.

FAQ | J-B Weld (https://www.jbweld.com/faqs)

Would use the 24 hour epoxy and not the QuiK 5 Minute type

Oh - yes and you can mix this with flox or the thickener that was previously suggested.

RW

[jrevens]

Purely based on adhesion and strength, epoxy (with flox or other suitable filler) would be the best choice in my opinion. However, I would really do a lot of research before using any particular brand/formulation. JB Weld advertises gasoline "resistance", but FWIW here are the results of an interesting test: http://www.v8buick.com/index.php?threads/fuel-resistant-epoxy-immersion-test-very-interesting-results.307765/ (http://www.v8buick.com/index.php?threads/fuel-resistant-epoxy-immersion-test-very-interesting-results.307765/)

[jmodguy]

There are resins for use with gasoline but they are not cheap and I have yet to find a source that will sell small amounts. Primarily used for underground fuel tanks.

[Rodney]

As usual, good info from Jrevans.

RW

[dogger]

Jb weld is not impervious to gas. It will hold up to it for about a year but after that gas will break it down and it will leak. Ive used i. In other applications and it is not a perminet fix.

[N14ND]

So what I have gleaned from the composite constructions sites (canard) is that the curing agent for fuel contact needs to be an aromatic amine, which is EZ POXY 87 hardener. ACS sells it in 1/2 gallon...$100. Plus you would need the Ez Poxy resin.
T-88 (aircraft structural adhesive- epoxy) technical data sheet says that it is "unaffected" by gasoline. I have built up many wood ribs with T-88, but never mixed it with flox, micro or chopped glass. I have emailed a technical question to System Three Resins and will post their reply.

[N14ND]

Here’s what System Three said:




Brian Morgan (System Three Resins, Inc.)
Nov 11, 3:38 PM PST
T-88 is not ideal for mixing fillers into, it is quite thick as is and getting a homogenous mixture is very difficult. Our General Purpose Epoxy (https://www.systemthree.com/products/general-purpose-epoxy-resin) would be a better choice for this application.
How to incorporate thickener and fillers into General Purpose Epoxy (https://support.systemthree.com/hc/en-us/articles/360006091094-How-to-incorporate-thickener-and-fillers-into-General-Purpose-Epoxy?source=search&auth_token=eyJhbGciOiJIUzI1NiJ9.eyJhY2NvdW50X2lkIj o3MzA2NzcsInVzZXJfaWQiOjM5NjYxMTczMzc3NCwidGlja2V0 X2lkIjoxMDM5OCwiY2hhbm5lbF9pZCI6NjMsInR5cGUiOiJTRU FSQ0giLCJleHAiOjE1NzYxMDI2Mjd9.v9ivx1vBjZp5ntZV5vA B_9TuCQx9d4nPGCfM8NjFdNE)
Are System Three products suitable for the fabrication or repair of a fuel or gas tank? (https://support.systemthree.com/hc/en-us/articles/360005899593-Are-System-Three-products-suitable-for-the-fabrication-or-repair-of-a-fuel-or-gas-tank-?source=search&auth_token=eyJhbGciOiJIUzI1NiJ9.eyJhY2NvdW50X2lkIj o3MzA2NzcsInVzZXJfaWQiOjM5NjYxMTczMzc3NCwidGlja2V0 X2lkIjoxMDM5OCwiY2hhbm5lbF9pZCI6NjMsInR5cGUiOiJTRU FSQ0giLCJleHAiOjE1NzYxMDI2Mjd9.v9ivx1vBjZp5ntZV5vA B_9TuCQx9d4nPGCfM8NjFdNE)
Best Regards,
Brian Morgan
Technical Support











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Airgti
Nov 11, 2:11 PM PST
Fixing drain boss in fiberglass fuel tank. Would like to use T-88 mixed with flox/chopped glass fill hole. Idea would be to drill out bad threads and tap to larger size. Fill hole with T-88 mixed with milled glass as a filler. After curing drill new hole and re-tap to accept fitting.

[Slyfox]

When fully cured, J-B Weld is completely resistant to water, gasoline, and about every other petroleum product or automotive chemical. For wet-surface or submerged water or gasoline repairs, try our SteelStik or WaterWeld. ... KwikWeld is a great alternative to original J-B Weld when you need a quick-setting epoxy.

FAQ | J-B Weld (https://www.jbweld.com/faqs)

Would use the 24 hour epoxy and not the QuiK 5 Minute type

Oh - yes and you can mix this with flox or the thickener that was previously suggested.

RW



I would use hysol, the stuff we use on our wings, before I would ever use that junk jb weld. I use hysol all the time with transmission fluid and it does hold up. not sure about fuel, but I would think it would work better than jb weld.

[Rik]

I don't know the name of it, but there is a material/paint that is white in color that the boat manufacturers use to coat the inside of the fuel tanks that is impervious to gasoline, race gas and some luck with the methanol fuels (E85) too.

Call a boat manufacturer and see what they use.

[jiott]

I had a fuel leak on my low fuel sensor chamber where the large plastic sensor fitting screwed in. I took it out, cleaned it up, and coated the threads with our standard Hysol and reinstalled it. It has been leak free in constant contact with fuel for 6 years now. I did the same with a leaking screw thread on a portable fuel tank (not part of my airplane) and it also has been leak free for about 5 years. FWIW