Welding fuel tanks

Simon · 03-19-07, 04:47 AM

Now I'm not capable enough to do this myself, but the inlet for my fuel tanks come straight out the front of the tanks for about 3-4 inches then stop. I'd rather they turned upwards. I'm thinking of getting an aluminium fabricator to weld some tube so they point upwards.
Now I know how dangerous this can be, but how about if the tanks were turned on end and filled right up to the neck with water? The only petrol fumes would be in the 2-3 inches of pipe sticking out. Would this be safe to weld?
Like I say, not something I will be tackling, just interested to find out.

Simon

Russ Noble · 03-19-07, 05:02 AM

Simon, water helps, but a better way is to purge the tanks with exhaust gases. Hook a hose up from the tailpipe of a car into the tank/s and run it at moderate speed until the tanks are almost too hot to touch. This will completely purge all the fumes out of the tank and also evaporate any small residues of fuel trapped in seams etc. This method is the best I have used. No problems.

Cheers

Frank Catt · 03-19-07, 05:09 AM

Russ, thats the way we do it too, Frank

Scott Calabro · 03-19-07, 03:29 PM

Brilliant !!!!

And to think I wasted a whole bottle of Dry Nitrogen last time

Brilliant !!!!

Best,

S

Malcolm · 03-19-07, 06:25 PM

If you are to muck about with your fuel tank, consider runing a better air breather line from the rear of the tank to the filler cap instead of the one from the front of the tank. It will help you when you fill her up with petrol.

Simon · 03-19-07, 06:34 PM

Thanks Malcom. The car originally had a fuel and return connection in the rear of the tank so I suppose I could now use the redundant return fitting.
Simon

Phil · 03-21-07, 11:31 PM

Simon
I am assuming that whoever welds your tanks will be using TIG process with argon, or argon/helium mix. Its easy to just purge with argon and leave the highest point open...or if you need to manuever the tank around to weld it properly leave a small bleed hole and weld away. I do a lot of tanks this way and never have a problem. Just let if purge for a few minutes to make sure you have a complete inert atmosphere.
Cheers
Phil