what is the safest way to weld a gas tank that still has vapors in it ? or what is the best way to clean the gas out ? thanks, mike
Safest way is to have it hot tanked. This will also give you a nice base to start your repairs from and then you can weld & reseal.
I've heard of this working, be careful none the less. My good friends forearm is melted from a tank explosion less than a week ago from welding a stud to pull a dent.
throw a match at it then after it burns out shoot air in it then repeat till there is no more vapor, or fill it with water, the exaust one sounds good
plumb your vehicle exhaust through the tank even when welding you will have no problems note make sure you are not preasurizing the tank also need a good vent.
Ive done the exhaust deal..works just fine. let it run in there untill the tank feels warm..about a good 20 minuets.. leave it vented so the exhaust can move thru it freely.. leave the exhaust going thru it..strike a match and hold it near the outlet..if it flares up..you need to run the exhaust longer..if it doesnt..start welding
Dry Ice! Done it a few times. Fill it as full as you can and weld away. Wear gloves when handling the dry ice though.
Somebody once posted the right answer on an earlier run of this discussion... Approximately "We just have the new guy do it, over on the far side of the parking lot."
The best way to weld on a tank is to run your inert welding gas [ Ar./CO2 mix] through it while welding on it. Just connect a Y valve in line [ one for the welder and one for the tank] and there should be no problems.
I remember a letter came through to Triumph dealers years ago, told them to use the exhaust trick, we tried it on a bike tank, and it worked fine.
I've always put some dishwashing soap in the tank and then filled it with hot water. Got lots of soap suds coming out, and then rinsed thoroughly and blew it dry with air. Always worked for me.
thats what i always heard, i used pieces from two propane tanks for my gas tank on my t, i filled them with water let them sit for a day just to be safe. it was scary to take a torch to it for the first time but nothing happened and turned out good.
we've been through this before ,HAVE IT HOT TANKED, cost 35 bucks here to do and then theres nothing to worry about,probably all have the same story lost a very good friend years ago this way, don't risk it.
We always cleaned the tank with a pressure washer, when you think you have it clean double the time. Make sure you blow it out with air until it is dry afterwards to keep any rust from forming. I have also seen people put a hose from their exhaust into the tank to displace the oxygen, we always shot some inert gas into the tank after cleaning. The seams are the killers; they can hold gas and air even after cleaning. If you are welding a seam, clean as per above and then pre-heat the area with a torch or an electric heat gun from a distance to evaporate anything in the seam. We had a couple of seams go BOOM even after cleaning, it tends to turn your nice square tank into a nice round balloon and scar the begeeezes out of you and hopefully that’s all. You can also lay a heavy blanket over the tank, just don’t cover the opening. Bob Vinton - BigSkyBob
I flush mine out with lots of water, then I pump in shield gas ( argon and CO2 mix) from a spare welding tank. I let the gas run while I'm welding. The shield gas will displace any oxygen, but you didn't hear it from me.
I won't vouch for filling it with water. Years ago I tried that, of course being a young dumb ass I had the tank sitting in my lap while I sat on a milk crate. Put a torch to it to weld up a small hole and boom, tank got a lot bigger. I'm lucky I was able to have kids after that!
People really overthink this stuff sometimes. What explodes? Fumes. What supports burning? Oxygen. How do you keep it from exploding? Remove the oxygen/fumes. How do you do that? Replace it with something that doesn't burn/support burning.
thanks for the info. i tried the exhaust pipe trick, and it worked great !!!! gotta remember that one ! mike
I filled mine completely full of water and welded the filler neck,let it sit in the sun and dry real good.
I purge nitrogen through the tank to displace the oxygen/vapor. In turn- it will also eliminate scaling on the inside of tank when welding the outside.
Greetings! What has worked for me in the past was to spend a few dollars washing the inside of the tank with hot soapy water, then dry the inside of the tank with the exhaust from a shop-vac. Once the tank is completely dry have your girlfriend check the tank for odors because if a girl can't smell it there's nothing to smell, then once all oders are eliminated the tank is safe to weld. Good luck, Mike.
The Jalopy Journal
