dom14 (12th May 2016)
Use a longish hose or run the hose through a bucket of water as they can get Dam hot.
Any BOC, Supagas or air liquide outlet can hire you a cylinder, but exhaust gas is the cheapest option.
As you won't have fuel in your tank to run the car use a motorbike or mower.
It's all the same.
2012 GU8
dom14 (12th May 2016)
Purging of the petrol tank is done to get rid of any left over petrol in the tank, right?
So, it won't "explode" while trying to weld the crack.
What if, after draining all the petrol, I leave the tank out in the sun for few hours for any left over intank petrol fume to get out??!!
I understand that means pulling the tank out. But, I always thought, in order to do a proper welding job of satisfaction,
having the tank on a bench is the ideal thing. Welding stuff under a vehicle(with no access to a hoist) is easily said than done.
While doing welding work on the van chassis(no hoist). I had to use quite a few of tree trunk cut outs to raise the van high enough to be able to do all the welding work. Even with that, it was a bitch of a job. I use the same thing to raise the rear of the vehicle high enough when I was doing the rear diff center.
RB30, some 2-3 inch lift auxiliary LPG tanks
Few more mods on the way
http://www.worldwildlife.org/species/tiger
https://www.panthera.org/
Cheetah Outreach
It won't rid the tank of fuel, but it will creat an environment where an explosion can't happen by removing the oxygen.
If you have no oxygen then no fire can start.
It is best to remove all fuel any way you can to be sure and to make sure you are happy with the process.
If you have a mig welder and can access the tank crack you will be okay as long as you can squeeze yourself or the welder in place.
We use to use this method to cut tanks in half and weld when fitting gas tanks and also for repairs.
Never ever had a problem.
2012 GU8
Since the crack was due to a stone, would you drill a small hole at each end before welding it anyway?
My advice is: not to follow my advice.
RB30, some 2-3 inch lift auxiliary LPG tanks
Few more mods on the way
http://www.worldwildlife.org/species/tiger
https://www.panthera.org/
Cheetah Outreach
RB30, some 2-3 inch lift auxiliary LPG tanks
Few more mods on the way
http://www.worldwildlife.org/species/tiger
https://www.panthera.org/
Cheetah Outreach
When we had cracked components on locos or whatever, we would drill a hole at each end if possible so that the crack would not continue after the weld was done.
Last edited by mudnut; 13th May 2016 at 10:30 PM.
My advice is: not to follow my advice.
dom14 (13th May 2016)
I'm sure you are right, as you have experience of doing it. I'm only trying to understand as I haven't welded a petrol tank before. I' guessing you use exhaust gas to purge any left over fuel(from hot exhaust gas)?
Or do you need to keep the engine running, while the exhaust is attached to the petrol tank & while you're welding?
RB30, some 2-3 inch lift auxiliary LPG tanks
Few more mods on the way
http://www.worldwildlife.org/species/tiger
https://www.panthera.org/
Cheetah Outreach