On 2009-11-23, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus25468 fired this volley in
:

It is not a purge, the jerry can will have water filling it almost to
the level of where I will do welding.

Iggy, fill it half-way full of hot water, add about a 1/4 cup of good
liquid detergent, and WASH it out. Then rinse, and see if you still
smell fuel. If so, repeat until it's only a hint of a smell.

THEN fill it almost full of water, and leave the cap off while welding,
so that if there is a small explosion in that tiny volume, it will vent
harmlessly.

I modify acetone and racing fuel drums thus all the time.

Lloyd, yes, I agree. I will flush the tank with hot water a couple of
times, and then fill it to displace ait prior to welding. With the
fill cap off, at worst it will be a little whoosh.

i