"Ken Davey" wrote in message
...
Jim Stewart wrote:
Nick Hull wrote:

In article SJPOe.1366$N22.1122@trndny07,
"Jon Grimm" wrote:


We've also use the exhaust from a portable generator =)


Ken Sterling (Ken Sterling) wrote in message
...

I need to make sure it won't explode and was thinking about
letting it sit in the sun open for a few days then fill it
completely with water. Any other ideas?

I've used the exhaust port from a shop vacuum piped into the tank
and just let the vacuum run until you're done welding. Moves
enough air that there is no build-up of fumes..... I've also used
water on smaller lawn mower type tanks.


My father welded many truck fuel tanks; he filled them completely
full and had an assistant with a fire extinguisher put out the
inevitable fire. Never an explosion.

Full of what? Please don't say gasoline...

I suspect that is what it was.
I have seen it done - welding on a full gas tank.
as was said - with a TRUSTED assistant standing by with a fire
extinguisher to put out the flaming welder.

Ken.

Three systems, and I've seen them all work:
1 - empty tank as much as possible, run exhaust gas (just the gas, not the
heat) from a vehicle into it, and allow the exhaust gas to displace the
volatile vapors.
2 - Completely fill the tank with water and weld it
3 - completely fill the tank with gasoline and weld it
The whole idea is to avoid flash point of the volatile vapors. On a side
note, when I was young and stupid (instead of being old and stupid), I cut
the gas tank hanger straps off a 1939 Ford Coupe which was upside down in a
field. There had been no fresh gasoline in that tank for 18 years, and,
luckily for me, the gout of flame went between my legs and 20 feet into a
field, which promptly caught fire. Be careful!!!



--
Peter DiVergilio
Most of the money I've wasted was mostly spent trying to impress people who
were never going to like me anyway!