Cheap fuel tank- accident waiting to happen??

slowrev · Sep 3, 2003

When I have welded gas tanks before, I washed them out good with water and then squirted a CO2 extinguisher in them for a bit then welded. This is sort of like the dry ice thing someone else mentioned. No oxygen = no boom.

hazmat · Sep 5, 2003

<font color="blue">I welded a GAS tank once for my old boss at work
He stuck a vacuum cleaner hose in it first, and presto no fumes inside.
Worked like a charm! </font>

Wouldn't recommend that technique. The motor on the vacuum can arc causing the boom before you even bust out the welder....

Henro · Sep 6, 2003

<font color="blue"> Wouldn't recommend that technique. The motor on the vacuum can arc causing the boom before you even bust out the welder.... </font>

Hazmat,

Your comment is a good reminder of how often one can miss the obvious. I was thinking of how we used to use a special meter to sample and test the explosiveness of the airspace in a room or container before doing any welding, or sometimes before even entering it. And wondering how I would ever be sure at home...

But the vacuum cleaner idea did not even try to ring a bell in my head! Then I read your post and could only think:

Hazmat hit the nail right smack on the head! /forums/images/graemlins/smile.gif So easy to miss the obvious...

theonlybull · Sep 14, 2003

i weld every day for a living, but i would never take the chance on welding a fuel tank.. my life's not worth it. i have seen desiel tanks go off, even hyd. cylinders that have gone off, and the bang alone is enough to keep me away from them.

bgott · Sep 15, 2003

I worked for a country blacksmith shop when I was younger and we welded fuel tanks all the time. It didn't pay to send work away when there wasn't that much around in the first place. My favorite way to do it was to fill the tank with water and leave it in there. That can be a PITA, the water pulls the heat from the back side of your weld so you have to pay attention or your penetration suffers. The water under your weld will boil and spit at you so you have to pay attention to your eye protection, raise your hood or googles ( depending on whether you were gas or arc welding) and you could get blinded by boiling water spitting through the part of the hole you hadn't welded yet. When you have a smaller tank welded at a radiator shop this is basically the technique they use, they just fill the tank and submerge it in their acid tank with the spot to be welded sticking out. We had a stack of old carbon tetrachloride fire extinguishers lying around, the boss liked to use them for tank welding. He'd just shoot a little in the tank after it was around 3/4 full of water. I didn't like that because I didn't like the thought of what would happen if you didn't squirt enough in. The third way he used was to run a hose from an engine exhaust into the tank to evacuate the fumes. I would go down to the corner bar and have a beer when he did it that way.