Welding Fuel Tank

miner09 · Jun 22, 2015

How is the best way to weld on aluminum fuel tank? I've had it done before but the local welder is not sure if he wants to weld it. No fuel in it. Thanks.

old · Jun 22, 2015

No fuel makes for the bigger bang then when it is full. The liquid does not blow up but the gas vapor sure as heck does big time. I know of 3 ways to do it.
#1 hook it to a car exhaust pipe and run the engine all the time your welding it and make sure you have had it running 30 minute or more before you try to weld on it.
#2 fill it with water and then weld on it.
#3 The one that gets most people if fill it with fuel then weld on it. I have done 2 that way and yes seems stupid but I am still alive and did not so much as get burned. One was one of those OH NO type of things and the other was out of need at the time

jon f mn · Jun 22, 2015

NEVER run exhaust in a fuel tank for welding. People do it without dieing all the time, but then people drive drunk without dieing or killing others too. That doesn't make either a good idea. Exhaust still has more than enough oxygen in it to allow combustion, and if it's auto exhaust they pump air into it so that's even worse. Filling to above the hole with water or fuel will keep it from exploding, but getting a weld that don't leak will be more accident than anything as both will cause even more problems with pin holes than you will already have. The best way is to purge the tank with argon preferably, or co2, then weld with the argon or co2 still blowing into the tank. Argon is better for aluminum tanks since that is what you use for welding.

Stephen Newell · Jun 22, 2015

I don't know about aluminum. I've welded a steel gas tank many times. The thing to do is open it up as much as possible. If there is any fuel fumes in a confined space it could explode but if the sending unit and gas cap is removed where it has a few big holes in it the most it will do when it ignites burn. I had one that still had a trace of gas in it and it made a poof noise and shot a brief flame out the holes a couple inches. The first time I welded on a gas tank I put a rag on a 10' stick and lite it and passed the flaming rag over the sending unit hole to see what happened. When nothing happened I preceded to weld on it.

Goose · Jun 23, 2015

My preferred method of welding on a fuel tank is to stand 100 yards away with my fingers in my ears while someone else does it. (I blew one once).

dr sportster · Jun 23, 2015

I like to use a picnic tables as a chest protector. That way only my head and arms will blow off.

edj856 · Jun 23, 2015

If you have a steam cleaner, tank the drain plug out of the tank, put the wand in the fill hole, and let it run for 15 or 20 minutes at around 200*. The steam will clean the tank and get rid of all the vapor. This is how we used to clean 9200 gal. aluminum tank trailers before welding or entering for inspections.

Mike M · Jun 24, 2015

You are so right on that ex trick. Do not do it ! I did it once and that was the only one I ever had pop on me ! I usually clean them good with high pressure washer and hot soapy water. Then leave as much open as possible and solder with acid core solder and propane torch on the steel ones. I also sandblast them to clean it good and find all the holes.

Billy NY · Jun 24, 2015

Whats interesting about doing that, is vapors will remain from the initial burn, you can repeat this many times before the vapor is combusted, each time its a little less volatile, and I attribute that to the fact that each burn will go out when the oxygen is burned off, but leave vapors. I did a small tank on a simplicity 4040 and it took several repetitions before there was no puff of flame. Let a little air in, it burns, goes out, repeat....

Stan in Oly, WA · Jun 24, 2015

But doc, you know that an explosion like that can be very powerful, and a picnic table might not be enough protection. Then, in addition to having your head and arms blown off, you could be badly hurt.

Stan

Billy Shafer · Jun 25, 2015

Guy I know hooks a blower to the tank. Goes for coffee about a half hour. Then welds with the blower going.Anything with fumes gets a day in the sun.

Welding Fuel Tank

miner09

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old

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jon f mn

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Stephen Newell

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Goose

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dr sportster

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edj856

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Mike M

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Billy NY

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Stan in Oly, WA

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Billy Shafer

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