Gas tank question 39 ford

Gary in Mozarks

Gary in Mozarks

Senior Member
Can anyone tell me how gas tanks were put together? Were the top and bottom halves soldered together? I have two tanks. one has a bad top and the other has a crushed bottom.
 
Seams rolled, welded, and tern coated. Open them up and you lose the tern coating if any is left anyway. Used anks aren't that hard to find being that repops are available in both steel and polyethelene.
 
ford38v8 said:
Seams rolled, welded, and tern coated. Open them up and you lose the tern coating if any is left anyway. Used anks aren't that hard to find being that repops are available in both steel and polyethelene.
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Well I guess that shoots that idea all to heck. I guess I will have to start saving up for a gas tank LOL
 
Gary I just took the tank for my 39 pickup to get boiled out, checked for leaks and coated. They said $175 max cost.
 
You could cut the top off the good bottom leaving the seam welded flange of the bad top on the good bottom. Cut the good top off right at the welded flange. put them together and weld them. G.M.
 
G.M. said:
You could cut the top off the good bottom leaving the seam welded flange of the bad top on the good bottom. Cut the good top off right at the welded flange. put them together and weld them. G.M.
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It probably sounds crazy to a lot of people, but I'm gonna try that. Being retired, I have more time than money, and having our daughter getting married in Oct, I don't have the 250 dollars for a tank. If I can't make it work, Im only out my time.
 
I don't know if 'fuel tank welding precautions' have ever been canvased on Fordbarn, but they certainly have on the HAMB. Please make sure you understand the procedures before attempting to weld on fuel tanks. They can be very dangerous.
 
Fe26 said:
I don't know if 'fuel tank welding precautions' have ever been canvased on Fordbarn, but they certainly have on the HAMB. Please make sure you understand the procedures before attempting to weld on fuel tanks. They can be very dangerous.
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True enough, I have braised and welded many tanks over the years. but I aways leave them open for an extended time and blow them out with air before I weld them and never on a car.

With both the sending unit and the filler open and 103 in the sun, It doesn;t take long to remove all vapors. These tanks havn;t had fuel in them in many years.
 
8/2/11 Years ago I cut the top off my 1940 gas tank to clean it out. I then tried to gas weld it back together and found that it would develop a hairline crack in the metal right in front of where I was welding. It was as if the metal had work hardened. Drilling a small hole didn't help either. It just kept cracking. I thought it was because it was made of ternplate. In anycase, I finally used fiber glass matt and covered the entire tank. It lasted 20 more years.

Gary in Mozarks said:
It probably sounds crazy to a lot of people, but I'm gonna try that. Being retired, I have more time than money, and having our daughter getting married in Oct, I don't have the 250 dollars for a tank. If I can't make it work, Im only out my time.
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When you oxy/act weld a tank back together, unburn acetylene gas will collect in the tank and the acetylene gas can blow it apart while you are welding on it. I use a running air hose to purge unburnt acetylene gas from the fuel tanks while I am gas welding them up. MIG welding doe not have this problem, but then there is the pin hole problem with any welds.
 
Using your car and run exhaust gas into tank about 15 minutes and will be ok for welding.But getting stuck on side of road with fuel problems isn,t any fun.I,d cut corners some were else.Buy a new tank.
 
Well, After several delays, (A wedding in Arizona, working on a airplane, etc) I finally got around to cutting those two tanks apart.

It went better than I expected. I cut the one with the good top, 3 inches below the joint, and I cut the one with the good bottom about 2 inches from the joint, so there will be at least a one inch overlap. The baffles are attached to the lower section, not to the top.

The only problem was one of them had some kind of sealer in it that was really nasty. I will sandblast the inside of both tomorrow. They seem to fit together pretty well due to the sloping sides. I will take pictures tomorrow and let you know how it turns out.

Gary
 
Gary, if there is a way for sand to get into your engine, it will. Sandblast your gas tank? I hope you feel very lucky.
 
SSsssteamer said:
When you oxy/act weld a tank back together, unburn acetylene gas will collect in the tank . MIG welding does not have this problem, but then there is the pin hole problem with any welds.
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dont worry about the pin holes. use tank sealer and brush paint the weld seam entirely several times until a thick coat has built up. ive done this several times on tanks that i couldnt purchase or that werent that bad but had holes just did a 55 army jeep tank a few weeks ago. had dirt stuck beside the tank and held moisture there for years. also the hole gives you a great hole to scrape out a lot of the bad junk from the tank. afterwards use the rest of the sealer on the inside of the tank. works real good and that stuff is specifically designed for fuel so it shouldnt break down or leak
 
Look up Redkote on Google. I have used this sealer in several dozen tanks over a 30 period. G.M.
 
ford38v8 said:
Gary, if there is a way for sand to get into your engine, it will. Sandblast your gas tank? I hope you feel very lucky.
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At this point its no longer a tank, but two steel stampings open on both sides. I really don't think its an issue.
 

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Gary, seal the two halve before you weld them, then you'll know the only remaining area to seal is the seam itself. Kinda obvious, I know, but these are the kind of dumb mistakes a do-it-yourselfer tends to make!
 
I've got to tell something that happened here. I DO NOT WANT ANYONE TO DO THIS!!!!

When I was 14 I worked for this ol boy that would only weld leaking tanks two ways. If someone brought the tank in he would run exhaust into it to weld it. ( which is good way to do it )

If the tank was in the car, he would make them go fill the tank full, then top it off with a can of gas he always had around. Then he taped the filler neck to seal it. Got under car, wire brushed around the leak, grabbed his torch and an old coat hanger (for welding rod) and welded up the leak. He always said " You can't burn gasoline, only the vapors." I stood and watched as he did this many, many times.

I always thought he was crazy for doing it, but now when I think about it, it was probably me that was crazy for standing there watching him do it.
 
ford38v8 said:
Gary, seal the two halve before you weld them, then you'll know the only remaining area to seal is the seam itself. Kinda obvious, I know, but these are the kind of dumb mistakes a do-it-yourselfer tends to make!
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Thats kinda what I had in mind, seal em except about 2 inches around the area to be welded/braised. I havn;t made up my mind yet which way I should do it. (weld or braise) I will probably try welding it first and if that doesn't go well, I will braise it.

Probably seems silly to a guy with a job, but for an old retired guy on a very small pension and more time than money, its an option. 300 bucks is not available at the moment. I got it blasted today and that came out pretty good. The sealer was really nasty. I still think it will work.
 
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