Bonneville America Forums Forums Technical Forums General Tech Repairing a hole in gas tank?

Hi! My TBA is doing fine but my girlfriend's Honda Nighthawk has a small pinhole in the side of the tank. It looks like the paint chipped and rust took over. Any tips on repairing? I'm thinking to draining the tank, take it off, clean it out very well, and let it dry for a month or two before doing anything. I thought I heard somewhere to fill up the tank with CO2 from a fire extinguisher and then braze it or weld with a wire-feed welder. Does this sound right?

yes and no. Flush with CO2 yes but do it from a source like a mig welder or beer tap to keep the dirt out like you would get from a fire extinguisher. Then braze or weld or if you are not after looks there is a 2 part putty called PC7 you can used that and if the metal was clean it will rust out around it before the putty would fail. We used to use that on tool wagons in the junk yard. With the PC7 no need for the CO2 just clean it and dry it very well and make sure good clean bare metal where you want to patch it,put that on wait over night and away you go.

Extra insurance, after however you fix the outside, use a product called KREEM to coat the inside of the tank. I've used it on a couple of shaky tanks and had great luck. It might even fix a pinhole if it is small enough.

Kreem works well but be very sure the inside of the tank is spotless so the coating doesn't peel off the inside. It's a real PITA to get out and will clog everything. The kit comes with muratic acid to etch the inside of the tank but clean the tank to the best of your ability first.

Thanks very much for the tips on fixing this!

I wouldn't use or trust epoxy for a gas tank repair....my choice would be lead...as a teenager, I worked in an auto body and radiator shop; we routinely repaired gas tanks by first cleaning them out with detergent and hot water, then filling them with C O2, and tinning a large area around the leak....once it's properly tinned, just fill the area with (lead/tin) solder....in the case of a gas tank and the cosmetic issue, I would create a minor "dent" around the hole and fill it with lead.....then, just wash the area with washing soda to neutralize the flux, prime, and paint!

What Michael says is probably the best way. PC7 will not fail if applied properly,if it help to a gas tank under a car being beaten to death through a junk yard, smashed against the ground and dragged it would certainly stay on a tank being treated with care.

I will say again though the lead is probably the best way,better than braze or weld because it involves much lower temperature.

Thanks for the tip about using lead to repair the tank. Although I was inclined to braze it, using the lower temperature for soldering definitely appeals to me to reduce the risk of deforming the tank. It's supposed to snow here tomorrow, so this will be a perfect fixit project.

what year is your bike? find some cheap tanks on Ebay

I think epoxy might be good. I hear they make it very strong.
Heck when I was a teenager we used lead too, epoxy hadn't even been invented.

hmm, I dont reccomend this as I dont know enough about it, but a friend of mine once welded a hole in a gas tank after filling the tank with water. No explosian, and the fix held
G

Not sure how good the weld would be but from a safety stand point filling with water does work. I haul scrap as part of my towing business and will take anything they can fit into a junk car. Well I got about a dozen propane tanks one time and I removed all the valves since that is what the scrap yard used to require to scrap them. Well now they want them cut in half, so I filled them with water and cut them in half with a torch.

PC7 is supposed to be aircraft grade stuff,weather it is or not I am unsure.

Another comercial for Kreem. I used it to seal scale and a pinhole leak on my 57 tank 12 years ago and it's still holding fine.

this is sad but I once "sealed" a leak in a tank with a self tapping screw. It held fine thru that summer. Geez i was a DPO as a kid.

Back in EMT school, they taught us to use Silly Putty to seal leaking gas tanks at crash sites.

Such a practice is probably forbidden these days.