WAIT! I think this is a common thought, but allow me a second to make you think... Fresh out of Paramedic school 7 years ago I responded to a report of a "large fire in a marina". From 8 miles you could see nasty, thick black smoke. When we got there, I immediately went to the guy with 3rd degree burns and blast injuries who was lucky enough to be thrown into the water. He told us that he & his buddy were to be working on a dry-docked boat, repairing the gas tank. Tank drained, flushed, rinsed many times. Filled with water to make it safe. He struck the arc, saw a flash, heard a boom and was in the water. His buddy (and mentor), a seasoned welder & boat mechanic, was not so lucky. He was literally blown over a 2 story building. Missed a picket fence by 3 feet. CPR was immediately started by some witnesses, but to no avail. The guy who did the welding recovered physically but not mentally. Ended up taking his own life. Be careful, man. I'd buy a new tank, life is too precious.
Ok that last story just scared the shit out of me! I AM DEFINATELY NOT WELDING THIS SHIT! No car is worth my 17 year old life! However I did try to close it up first with sheetmetal, gasket paper and sheetmetal screws BUt the screws won't pull the new metal tight enough to seal. There's a big noticable gap no matter how tight I do it. I am gonna post pictures soon to show you guys what I have done so far.
Exhaust the tank with fumes from a running car....it will displace the gas fumes in the tank, pretty hard to weld something full of water...
I had to modify the tank in my 37 Chevy pickup about a week after I got it on the road. Emptied the gas out, then spent about six bucks at the car wash on hot soapy high pressure water. Couldn't smell any gas after that, so we passed a flame over the openings in the tank. No boom, so we welded a sump on without problems. I think the high pressure soap helps. Be careful, be smart. Ralph
Wash it out until you can't smell anything. Then bring it to the radiator shop. Mine charged me 30 bucks. It just aint worth the risk...
The thing here is to fill the tank with something that gets the air out. The gas fumes can't burn without air and it can't explode if it's not contained. Exhaust works well because it fills all of the tank, no pockets. Water works well if you can get all of the air pockets out. By the way about a year ago a guy at a local radiator shop blew up a gas tank he had boiled out and was welding. He thought it was clean and didn't fill it with anything.
Filling it exhaust fumes works great. I've done it a few times with no problems. I had a 500 gal propane tank converted into a cooker years ago. The guys that cut the door for me used the exhaust thing to do that. They said they had made many cookers that way. Just be sure to let the exhaust run into it at least 20 to 30 minutes before starting, and I always let it run while I was welding.
I know were you are coming from. Years ago I was laying under a mustang cutting a rear when I hit the tank with the torch. There was a load pop and I almost pissed myself. I got out from under the car and seen that the truck lid was push up and after opening the trunk the top of the tanks a mangle piece of metal. Second one was I lost some friend one night when they were welding on the race car and hit the tank. The thing could fire and killed three of them. some of yous from this area may remember it. It was the 666 that ran at Nazareth. I will not even think about welding on a used gas tank. I will use PC-7 or the new glues that they have for gluing body panels.
We don't even mess with this as an option our shop. Spend the money and buy a replacement. Beyond hoping for success in not setting off a bomb, you are talking about part of your fueling system, and you don't sound like you weld professionally. Small gas leaks could develop after the fact, even if you pressure test it. Keep your hobbie safe.
I remember from my Army days and mechanics training I had there that it was written in the Army Field Manual that purging a fuel tank with carbon monoxide was the correct way to prep a fuel tank prior to a welding repair. It had something to do with the weight of the CO gas. It would displace all other gases in the tank. It also specified a time period to pump the CO into the tank and some other prep work before you would do the repair. I used this technique with no problems, but only after I emptied the tank and then thoroughly flushed it out with water. I used a oxy-aceytlene torch and brazed, rather than weld the repair area. I felt that the brass would flow into the repaired areas better and reduce a chance of having a pinhole that would require repeating the process again.
Your absolutely right. I have welded many diesel fuel tanks with no problems. Completely different. Gasoline is far, far more combustible.Theres no comparison.
FWIW, a brand new repro 49-54 Chevy gas tank is like $200. I wouldn't even spend the money to seal one for that cheap. And I'm one of the cheapest bastards around.
.....When you fire up a torch.....and head toward the tank with brass rod in hand......anybody else in the shop will damn near tear the doors down leaving !!! I've done.....don't recommend it......wont do that shit again !
use epoxy weld then use por 15s tank sealer the stuff is worth every penny and then some<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> <o></o> <!-- / message --><o></o> FWIW, a brand new repro 49-54 Chevy gas tank is like $200. I wouldn't even spend the money to seal one for that cheap. And I'm one of the cheapest bastards around.<o></o> <o></o> <!-- / message --><!-- sig --><o> IMHO, these two HAMBers have the best advice. I had a '62 Plymouth that I used as a "beach car" at Daytona for many years and the ocean got to the gas tank. No one I knew wanted to weld on it so I tried the epoxy and the POR15 (which was pretty new at the time). It did the trick. </o> <o>Later, I found a tank off a '64 Dodge at a local wrecking yard (which being an SC wreck was rust free) and put it in. You only have one ass, try to save it.</o> <o></o>
yeah welding is out of the question. I was wondering if you guys knew if JB weld is good with gasoline... long term wise. Thats what I am gonnna do today. Just JB it and maybe put some por 15 like you guys said. I found a new tank and ran it by my bro (his car) and he refused like the cheap hard headed ass he is... anyways.... Will let you guys know how the JB goes.
When I had to patch the gas tank around the outlet on my'58 John Deere tractor I flushed it well, then dropped in a couple pounds of dry ice and a quart of water. Put the cap on and watched the fog come out the hole, then started brazeing. My dad tried to weld a couple of old 250 gallom gas tanks together to make a big water tank. They'd been dry for years, etc. He rode one of them out of the bed of the truck. Uninjured, but made for good safety lesson!
I have tried JBWeld on a gas tank, just make sure that it wasn't solder-dipped. The tin in the solder won't let the JB set-up at all. I know I waited for 2 weeks, and it still wasn't set up.
I moved my 54 chevy gas tank filler neck from the side of the tank to the middle so I could shave the gas door. I washed the tank a couple of times with dish soap and water and let dry. I then filled the tank with some dry ice (get it from the grocery store). Don’t weld until there is a decent amount of white fog coming from the tank hole. I used a 110 mig with flux core wire. You can also run a flame from a stick over the hole at this point to make sure there are no fumes coming out of the tank. When the dry ice melts the gas carbon dioxide fills the tank. Carbon dioxide is heavier than oxygen and pushes the oxygen out of the tank. No oxygen no explosion. Like said above this is mentioned in the military welding manuals. Fighter aircraft at least in WWII was filled with inert gas (I believe argon) as the tank emptied to stop bullets from exploding the gas. Its not luck when you don’t explode there is a right and a wrong way to do anything.
I repaired gas tanks for a living a few years back, I would recommend sodering the tank. If you have the right tools is very easy. everything needs to be real clean and you need a large sodering iron that you can heat with a torch, away from the gas tank,. tin all your surfaces well and move slowly around the patch. You will have to reheat the iron a few times , it takes practice ,but its not rocket science, I would never use an open flame on a used tank, but thats just my humble opinon. carlg
about 7 years ago, I j.b. welded a quarter to the BOTTOM of a 56 Merc tank to patch an accidental puncture hole (don't ask.) it's still on there. and it doesn't leak.
..I've used a product called "Poxy-Weld' a lot like JB weld, it's a 2 part mix., sets up hard as a rock, good with all liquids, they say you can drill and tap threads in it. I find it at Menards home centers.
I have welded on many tanks, make sure you fill it with a constant flow of argon and it will be fine. I welded a diesel tank with diesel in it on a ship we sold to the Venezualins, 30,000 gallons of fuel to be exact. Gas is alot more combustable, but if you keep a steady purge you will be fine.
Article in todays newspaper, a guy was drilling a hole in a gas tank filled with water. Something went wrong. The guy is in the hospital with second and third degree burns. I suggest that you either get another tank or take it to someone who does it all the time.
I appreciate all the help. I still have some cleaning to do, but after I am gonna try the JB weld or epoxy. It just seems easier and safer. I personally dont think my welds would seal anyways... those ideas are really clever though. They make perfect sense, because all you need to do is displace the gasoline fumes...
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