rolande replied:

Bob,
Would think the cost of a professional welder to repair and test would be worth more than the cost of losing the fuel tank if something did go wrong
Rolande

MJS replied:

Bob,
As a fitter i would strongly suggest you don't repair the tank with a stick welder yourself. The way to repair the tank is with a Tig or oxy welding.
The best way to prep the tank is to flush with water several times, then fill and continue to top-up with CO2 (fire extinguisher) during the welding process.

Having said this, the cost to have the tank repaired shoud be minimal.

Hope this helps.

Cheers,
Marc.

Member - Davoe (WA) replied:

Dont you put water in them to weld a fuel tank?

floyd replied:

never ever ever put water in the tank. It will start rust immediately then it will be there for life.

Leroy replied:

Bob,

It cost me $200 bucks to have a bracket rewelded and strenthened that held the tank, have cracks welded in tank, remove and refit tank.
Since you have removed it I would expect the cost of someone doing the welding for you to be minimal.

Leroy

Member - Nick (TAS) replied:

Broke a bracket on the sub tank on our 4 Runner which let the tank drop down onto the road and was dragged 100 odd metres before we stopped,result slow seep along the seam.Removed tank,flushed with water a couple of times,hooked onto exhaust for a while then migged up no worries.Once finished I put the end of the heat gun into the filler and left it there for 1/2hr.Tank got that hot you couldnt touch it,no water left in there fo sure.I wouldnt try welding a petrol tank either.

Bilbo replied:

I woouldn't try welding a petrol tank without steaming it out for 24 hours. Seen a few go BANG! big time - even after water washing.

I like the idea about putting exhaust gas in it. However carbon monoxide is combustible (it will burn) if you get the temperature high enough.

I've had success with soft solder in the past. It's just sometimes difficult to get the seam clean enough to seal off with solder. Patience is required.

Bilbo

Wayne (NSW) replied:

Bob,

A mig weld would be better.

The last time I had to weld a used fuel tank(petrol) I filled it with exhaust gas from another vehicle, kept the area cool with water after a short run of weld.

Hope this helps.

Wayne

Member - Geoff M (NSW) replied:

What we are after when welding a fuel tank is to displace the fumes with something non-combustible. That can be water, CO2, Nitrogen, Argon, Carbon Monoxide etc. Basically most all of these will work.
For me, I've usually TIG welded tanks for a couple of reasons. Mostly this process doesn't burn off great areas of whatever the tank is coated with to prevent corrosion. Gal, zincalume, powder coating etc.
I've found Oxy welding works well but heats too large an area and as stated above, burns off the coating over a percentage of that area.

Geoff.