Welding on gas tank

[flousberg]

Does anyone have a bulletproof way to weld on a gas tank. I need to weld a plate on for the sending unit and in tank pump.

Thanks

 

[Clint]

Does anyone have a bulletproof way to weld on a gas tank. I need to weld a plate on for the sending unit and in tank pump.

Thanks

Never done it myself, but what Ive been told: clean clean clean with soap/water/brush. Get it very clean, then fill it with water while you weld on it. Gas will just burn, but the fumes can explode, so if you can keep those away there shouldnt be a problem...

 

[Brewbro21]

I was told the same thing from a weld shop. Fill with water so there won't be any fumes left inside.

 

[Revelation]

I would take it to a Radiator shop and let them do it, welding and gasoline are wicked dangerous.
but if you must do it yourself
BE SAFE, Wear only 100% cotton clothing if you do not have any Fire Rated clothing, 80% of the injuries sustained in a fire are from the continued burning of clothing, NO POLY COTTON BLENDS.
Then
Fill with water, add powder laundry detergent, get it nice and bubbly. clean and prep the area for the weld weld, drain rinse, dry, re-install.
The powdered soap was from the FD when we had a major gas spill at the service station I worked at.

 

[knack]

Years ago a common method was to run a hose from the exhaust pipe of a car into the filler neck of the tank, and keeping the exhaust flowing while welding. I've seen it done many times - but I wouldn't try it. I'd be really worried about filling the tank with water and welding it too. The slightest little air pocket would turn into a bomb when the metal got hot. I wouldn't take the chance.

 

[flousberg]

I am going to be cutting out a 5-1/2" X 5-1/2" hole in the top and welding in a plate for the new sending unit and pump. Everything will be pretty open. I pulled it last night and drained it. I plan on blowing air through it tonight for about an hour with a shop vac to try to evaporate the gas and move the fumes out. If I had a way to slowly heat up the tank to about 150° without an open flame and blow air through it I know it would remove any danger, but I am not sure how to do this.

The filling with water scares me a little because the gas and fumes will rise to the top and if they get trapped in the tank then it could explode. Otherwise I think the danger would be fire instead of explosion. I heard about steaming it for an hour, has anybody done this?

 

[bronko69er]

You could always try purging it with your welding gas so there's no oxygen left to burn. I haven't done this myself but it seems like it would work.

 

[deltarat]

Fill it with the soapy water with the filler neck at the highest point will force the gas out the top. I have cut and welded many propane tanks with the exhaust in the tank method.

 

[45acp]

I helped a buddy do his rear tank- we filled it with soapy water and let it sit overnight. Drained it the next day and welded away.

 

[surfer-b]

I cut out and welded the in-tank pump for the FI, I used the mustang pump, anyway I removed the tank, drained it and let it sit outside in the sun for about 2.5 to 3 weeks then filled up with water and started cutting. Be carful with the shop-vac that electric motor has countinous spark to it, don't get too close to the tank with it. You might think about using air from your comp. if you have one. Whatever I would let it sit for as long as possible to air out, I'm sure there other things that can be worked on.

 

[deltarat]

It would be a good time to use the por gas tank kit to stop it from rusting.

 

[bmc69]

We run a constant flow of nitrogen purge gas through the tank the whole time we are welding on it. And that is after a thorough cleaning with a good detergent solution.

Old tanks with a lot of scale and crud in them..won't touch those. The fumes continue to out-gas from the crud and scale no matter how much you try to clean the tank beforehand. Had one let go on me years ago..fortunately it do not explode. More like it 'wooooofed' and the end result was a rather much larger (and useless) tank than we started with..%)

 

[flousberg]

My tank it only about 2 years old with no rust.

 

[DuneBuster]

Wait until near dark.

Get a buddy to weld it with the exhaust line feeding the filler tube.

Get some popcorn

stand, oh, about 50 yards away or so

Give him the signal to start

oh, and wait until the 4th of July to do it...

I'd say the whole thing about emptying the gas and filling with soapy water will help expung any flammable gas, and the water is a quick way to quench welding if things go awry.
I guess the unspoken thing is that gasoline itself is not the problem it's getting all 3 together: spark, gas and oxygen that causes the problem.

 

[bronko69er]

Wait until near dark.

Get a buddy to weld it with the exhaust line feeding the filler tube.

Get some popcorn

stand, oh, about 50 yards away or so

Give him the signal to start

oh, and wait until the 4th of July to do it...

I'd say the whole thing about emptying the gas and filling with soapy water will help expung any flammable gas, and the water is a quick way to quench welding if things go awry.
I guess the unspoken thing is that gasoline itself is not the problem it's getting all 3 together: spark, gas and oxygen that causes the problem.

Don't forget the beer! and the famous last words "watch this".

So just fill the whole thing with gas an you'll be set!
Just kidding don't do that.

 

[frdbronco73]

I have used dry ice welding on tanks at work and havn't had a problem.

 

[instigator]

anyone that welds on a gas tank is a FOOL, i had to work a death at a savage yard years ago where a dummy was welding on a gas tank with water in it and the tank ignited ,we never found the welders head

 

[Broncobowsher]

I have used dry ice welding on tanks at work and havn't had a problem.

This is how I know people to do it. Drain tank, flush with soapy water solution several times. Put in the dry ice and let it sit. Tape over the extra holes so there is no flow through ventalation. Weld away.

At work we have to ship used gas tanks from time to time. What a PITA! We have a special solvent that you put in the gas tank, slosh around with water, repeat. Keep going until the safety inspectors probe shows all clear. and we get the sign off to ship.

Fun ones are cutting up used propane tanks. I have a 1000# capicity tank in the backyard that is used as a fireplace. has twin scuba tanks welded on top for twin chimneys. Used a plasma torch to cut it open, after a ton of prep work. Still nerve racking.

 

[Pa PITT]

I've got a 250 gallon LP tank I took out of the ground 10 years ago I want to make a BBQ pit out of it ..We even moved it to the neighbors house last winter to start but neither of us has had enough balls to make the 1st cut....

 

[deltarat]

I have welded gas and diesel tanks and cut the tops out of many propane tanks with no problems. Wash them out well, exhaust in the tank and weld or cut. Dry ice is also a good idea. Yes there are terrible stories of idiots that have done stupid things, but anything can be done with the proper steps. Have you ever seen pipe fitters replace pipe in a gas pipeline? There are terrible accidents on the highway, but we still drive, but try to do it safely.
After you prep it, light a pack of firecrackers over the hole with a long fuse to check if it is safe from a distance away.