I need to seal pinhole in a petrol tank without welding?

i have a leaking petrol tank (pinhole size) Can it be fixed without welding?

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OK clean it and fiberglass works great I have rebuilt entire gas tanks with it, funny all of them on Fords vehicles.

However if it is just one hole a sheet metal screw and a rubber washer.

When you screw the screw into the pinhole the rubber washer seals the hole.


I used a similar method on the top of a badly neglected motorcycle tank about twenty years ago using small round headed screws it had about twleve pinholes in a cluster about three inches across; when a friend asked what all the little bumps were I said they were braille filling instructions for the former owner who was blind; it took him about ten minutes to realise what I had said ;-)

Now that was funny ;-)

Bondo is usually a body filler for more or less cosmetic work - I doubt that it would withstand fuel contact.

I'd recommend various gas / fuel / petrol tank epoxies.

Go to Google / Amazon / eBay / whatever and look for "gas tank epoxy" or "gas tank sealer". If the site has a rating system, go for the higher-rated ones and check the comments as well. Carefully read the supplied instructions and use / apply exactly as described.

Results include Permatex 80884 Gas Tank and Radiator Repair, J-B Weld 8267-S SteelStik Steel Reinforced Epoxy Putty Stick, J-B Weld 8277 WaterWeld Underwater Epoxy Putty, the list goes on. You will need to choose your epoxy based on the material your tank is made out of.

Bondo is fibreglass base and should be fuel proof.

You are correct:
Checking 3M's FAQ it indeed states that Bondo is gasoline-resistant, but it can only be applied to metal tanks and cannot be submerged in gas.
I still think epoxy is the better choice though.

JB Weld for certain.

nkerr19383 years ago

I bet JB Weld would work also

iceng3 years ago

I solder closed a puncture in my gas tank.

Don't use a propane solder pencil !!!!

Use a grounded electric solder iron.

Gasoline specific heat does not sink heat away like water would allowing solder to wet a steel tank with fuel and seal the hole.

iceng iceng3 years ago

BTW I was young, and kind of impulsive ... and

Gasoline did not have carcinogenic additives those days.

You don't say where you are in the world, so its hard to be specific, but you should look at "POR-15" and their tank repair kit.

rickharris3 years ago

Bondo or equivalent, you can or could here in the UK buy a petrol tank patch - probably illegal now.

Really you should look to change the tank. IF it is leaking in one place - It will be leaking in others soon.