Patching a gas tank

Bikeguy Joe

Bikeguy Joe

Godfather of Motorized Bicycles
Anyone know what works to patch a pin hole?

In the past, I have tried Seal-All, JB Weld and some other types of epoxy with good results....for awhile, then it seems the gas always comes through.

Anybody KNOW what works fo'sho'?
 
Well, after thinking it was muffler run-off, or I must have spilt gas all over my bike at the gas station, after careful wiping and inspection discovered a crack where my tank rubbed against my frame, up front, top of the groove.

So far I sanded the area, wiped it with acetone, then poured acetone on the crack, then put seal all on it. I used the acetone to make it penetrate the crack better.
Then I am going to sand it a bit again, put some JB weld on it, paint it, then instead of two small strips of innertube, I will use one long strip between the tank and the frame.
I wonder how long that will last, then I will get me self into brazing.
 
I would not braze on a used gas tank !! I have watched an old time welder solder a car gas tank useing a big electric soldering iron, and he told me NEVER put flame to a gas tank! Hope thats helpful.
 
Joe, I would try a 100w soldering iron, some flux and 50/50 solder. Just clean the area real good with sandpaper and maybe some steel wool first. I have patched many pin holes that way over the years. You can sand the solder a bit to blend it in. If it's something that'll show just dimple the area, fill it with solder then sand it level with the tank. It'll work.
Good luck, Dan
 
tim turbo said:
I would not braze on a used gas tank !! I have watched an old time welder solder a car gas tank useing a big electric soldering iron, and he told me NEVER put flame to a gas tank! Hope thats helpful.
Click to expand...

Of course I would take the time to make it safe. And even then I would be really cautious.
 
Ditto, what Tinsmith said. I've used this method on two tanks in the last couple of years. Solder, applied correctly is the only permanant way to fix pin holes. The key is to get the area absolutely clean. I like Nokorode flux and 95/5 solder. I do use a torch but very very low heat; just enough to get the solder to flow. Don't use flux core solder.

Good luck, Joe. Let us know what happens.

Tom
 
It won't be aesthetically pleasing, but you could try putting a self-tapping roofing screw (kind with the rubber gasket on it) into the hole and screw it down. I don't see why that wouldn't work.
 
F73ME said:
It won't be aesthetically pleasing, but you could try putting a self-tapping roofing screw (kind with the rubber gasket on it) into the hole and screw it down. I don't see why that wouldn't work.
Click to expand...

Screw combined with JBweld or epoxy has gotten me home in a pinch.
 
A screw and seal all fixed a hole in my oil pan in the car I once owned.
I drove it for years that way.
Didn't leak.
 
loctite makes a gas tank repair putty.
its an epoxy putty,sand ,cut off enough to make the repair ,knead it and squeeze it on.
for pinholes you would need to make hole a little larger.

up here i use tech steel,its very similar.
oil pans and gas tanks worked very well.

painting the repair will make it last longer also.
 
Thanks everyone.

In the past, I have tried Seal-All and various epoxies, but the additives and alcohol in gasoline seem to work their way through after a few days.

I think I'll give the soldering a try, I am pretty good with that and I have all kinds of solders to choose from, including silver solder.

I'll keep you posted with results.
 
Joe, silver solder requires more heat then the rusty metal will probably take. Stick with soft solder, either 50/50 or 95/5.

The process is a lot like leading in we used to do on car bodies. The heat is critical to get the lead to flow but not ball up. Like Tinsmith said, make a dent so the lead has a slight depresion to fill. That will allow more material to seal and give you something to level out later before sanding and painting.

Tom
 
I sealed a pinhole made by a cable stay on my frame quite a while back using gas tank repair putty. As tooljunkie said, cut off a bit, knead it together to activate the epoxy and press it over the hole. Smooth it out and once it hardens you can sand and paint it if you want too. It's got to be over a year ago I did it, and until now I haven't even thought about taking a look at it.
 
I hope you're not talking about a $2 stock tank, because if you are someone needs to slap you.
 
lol. No, it's for a XS750 Yamaha I am working on.

The guy was told the petcock was leaking, paid a bunch of money for re-build kits, and after he had them put them in it still leaked, then they wanted him to spring for 190 dollars worth of new petcocks....I looked at it, and could see where it was leaking from near the petcock.

skalliwags!
 
One thing that will easily fix any gas tank would be Caswell Tank Sealer, but it cost like $40. There's enough to do more than one tank though.
 
KBS is another tank sealer. It works well and comes in a kit with 3 solutions to clean, etch and seal the inside. I'd still want to lead in the external pin holes and not rely completely on a coating inside.

Found this old thread, Joe. There's a picture of a tank that I did some lead repair on. http://motorbicycling.com/showthread.php?t=29081

Tom
 
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As usual, NICE WORK Tom!

I think I am going to solder. The hole it very tiny (seeping) and underneath where it is not visible.
 
if it's an older tank that's likely to get more pinholes in it, i'd spring for the Caswell epoxy sealer and do the whole tank.

i just did the new tank i made for my new bike, and that stuff's pretty awesome. way better than kreem. it seals up pinholes, cracks, and uh, my not-so-professional welding mistakes...
 
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