MTFCA Forum

Trying to finish up this 11 torpedo roadster I have a new gas tank bought 25 years ago. Right in the center of the the end it has a pin hole or maybe a little bit bigger than a pin hole leak. It is about 1/16 in diameter. I found it when I have removed the paint. The gas has been out of the tank now for 48 hours. Looking for suggestions on the best safe repair. My initial thought is to dimple it and solder it and then do the body work on it and paint it and be done. I would use a soldering iron. I have tried JB weld steel and it didn’t hold. Anyone want to share their experiences in repairing something lake this safely?

Using JB weld to attach a sheet metal patch should work. Proper surface prep is important.

Using heat on any tank that has had fuel in it is scary.

Thoroughly clean it with saturated steam and you can do whatever you want, though I would think in this case you could fill it with water, drain off just a tiny bit, turn it on end, and flow it shut real quick with your TIG using silicon bronze. Purging with inert gas is an option too, but I've never felt comfortable with knowing when enough is enough.

A large soldering iron would work, but under no circumstances a torch! The question would be: Why would it have a pinhole leak? Is it rusted out on the inside? If it is, you might have more problems coming up. I once tried filling with water and using a torch. I couldn't get it hot enough to solder. Then I drained the water, and there was still enough gas to cause the tank to jump about a foot when I heated with the torch. it is almost impossible to get all the gas or fumes out even with water.
Norm

It was new like 25-30 years ago and then they shrunk it to do the bodywork on it they ground through it. I’m assuming that they beat the curve it on a lead shot bag. Then they leaded it and missed it. They come primed so I painted it and it started leaking right away. I won’t put a torch on it. That scares me to much. I wish I could find another new one but haven’t had any luck.

Clean it out as best you can, (wash out with some kind of detergent, or Simple Green, or equivalent. then rinse, then use some rubbing alcohol to get rid of the moisture, and THEN let it dry in the sun for a couple days.) When you are ready to apply the soldering iron (One of the old, big FAT ones, not a new, tiny, girly-man, electric wire soldering iron) (I have a 100 watt, big fat iron that I use on soldering sheet metal) go get some dry-ice from your local grocery store, and let that melt/evaporate/sublimate in the tank. Before the dry-ice is completely gone, do the soldering job. No torch, and the tank is filled with carbon dioxide to keep the explosions away. Plus, with the washing, you should be well below any flammability level, and alcohol will have evaporated and departed the tank in the sun.

Take it to a radiator shop. They are super good at this kind of thing and should be able to repair it easily and well.

I'm sure it's been mentioned here already, but just buy a new one! You'll have a lot less problems with it than you're likely to have repairing that old one.

I watched a guy prep a tank for welding and he just put his torch right in the open spout and there was one good blue flame puff out the spout and that was it, then he went about welding it with no further issues. The prep took about 5 seconds or less and he welded right on the tank. He said he has been doing this for years and this is all the prep he has ever done.

I worked at a radiator shop in my youth and we repaired gas tanks. fill and dump with water three times. stick the torches open flame into the filler opening. You MIGHT get a small huff but probably not. Clean to bare metal and solder a oversize copper patch over the problem area with acid core solder (if you can find acid core solder) I know I will catch hell by posting this method but the radiator shop I use to work at is still fixing gas tanks this way. bobt

I seen a guy put a hose on his tail pipe of his pickup and the other end in the tank, and started welding

If, and I say IF, the hole is a rust through, it won't the only one. You will have more soon IF it is a rust through. I suggest a quality fuel tank treatment. There are several out there, some better than others. I have read reviews on several touted to the "the best". Seems like all of them have the same great and not worth a crap reviewers. I believe the reason to be the reviewer themselves. The PREP work is essential for a product to work properly. IF you have one rust hole, then your whole tank has a rusty inside bottom and the whole thing needs to be treated with a good sealant or it will be just a matter of time before the next hole happens.

Good Luck,
Terry

I shined mine up with 80 grit paper and JB weld it then put the white gas tank sealer from snyders and it has been great for over a year now...

Fixed. Like I said it was a new tank that they ground through. Filled the tank with co2 and one tinny shot with my mig welder. I tried to buy a new one and I was told that they are being discontinued which if that is the case we will be fixing a lot of original torpedo tanks. Thanks for everyone that gave me advice!

I've brazed motorcycle gas tanks without incident more than once. If you wash it out with soap and water AND LEAVE THE CAP OFF I don't see what the big deal is.

While there's still gasoline in the pores of the metal that will be released and burn when heated, it's the CONTAINMENT of the combustion that poses the danger.

You'll have to make the judgement on safety for yourself. The only difference between a car and a bike tank that would seem to matter here is the ratio of cubic inches of vapor vs. the size of the opening.

Martynn I heard they are not making the tanks any more. The guy that made them retired????

One time I had a tank with a punch hole in it and a guy cross town said he could fix it. Just pull it off and take it to him, he'd need maybe 5 minutes..

I was intrigued.

He sets it up, takes a swat at it with his air sander...

Grabs something that looks like a gray Tootsie Roll and tears off a chunk...

Mushes it in the hole and then took his rubber hammer to 'the wart'...

Came out as a use as is finish...

I was a bit of a disbeliever in a putty solution and he told me no worries, he did it all the time and never had a redo...

I ran that tank for years and it never even weeped. Probably still holding fuel somewhere...

I just looked online to see if I could find it. Nope...that was a long time ago when lots of good stuff could be had if you knew where....but do see that JB Weld has what looks to be the same thing called 'tank seal' and at 11 bucks a tube probably worth a try.