Gas tank welding

[McKilla Guerilla]

First things first. I am not molesting my FJ. I love it much too much to harm it in that way.

I am building a cafe racer. Does anyone know how I can purge the fumes out of the tank before I weld it? Should I fill it with water & then just use a good tank sealer when Im done?

[FJmonkey]

First things first. I am not molesting my FJ. I love it much too much to harm it in that way.

I am building a cafe racer. Does anyone know how I can purge the fumes out of the tank before I weld it? Should I fill it with water & then just use a good tank sealer when Im done?

A continuous feed of inert gas to displace any flammable gas would do the trick. You could use the same shielding gas that you weld with. Give it a good purge and then keep the gas flowing till after the weld cools. It will work even there is gas still in it. Just not recommended mind you, I won't test it myself....Weld it under water..... How do welders repair fuel tanks?

[bcguide]

I have welded tanks with fuel in them using the exaust from a pick up truck. Run a hose in and don,t start welding until the tank is warm to the touch. Keep the
exaust to the tank while welding.

[McKilla Guerilla]

There is no fuel in the tank, hasn't been in years. I just don't want the thing to go bang if I put fire to it. I should've clarified my question also, I will be plasma cutting the tank apart then welding it back together.

I would never weld a tank while fuel was it it altho I understand the concept. it is the fumes that are explosive.

[bcguide]

I would still purge the tank with something while I cut it apart.
I have heard that there are cleaners you can clean the tank with before welding or cutting but do not rember what they were