Thread: Welding fuel tanks

To be on the safe side you are better off soldering it with a heavy duty soldering iron. Pre-tin the areas and if you neet to patch holes use pre-tinned copper sheet.

That is the method I have used.

Welding and soldering are very different. I've heard of people purging fuel tanks with diesel exhaust to avoid them blowing up as even with cleaning there may be residue.



Why oxy and solder? A large high wattage soldering iron would be much safer.

Originally Posted by isuzurover

To be on the safe side you are better off soldering it with a heavy duty soldering iron. Pre-tin the areas and if you neet to patch holes use pre-tinned copper sheet.

That is the method I have used.

Noted. Thank you

Originally Posted by flagg

Welding and soldering are very different. I've heard of people purging fuel tanks with diesel exhaust to avoid them blowing up as even with cleaning there may be residue.



Why oxy and solder? A large high wattage soldering iron would be much safer.

I can weld and can solder. I solder better than I weld but that's only due to how often I weld.

I was going to use oxy as the heat from the soldering iron would probably get dissipated fairly quickly. That's unless I get a whopper of an iron

Originally Posted by flagg

Welding and soldering are very different. I've heard of people purging fuel tanks with diesel exhaust to avoid them blowing up as even with cleaning there may be residue.

...

Diesel exhaust still has enough air to go bang. If they are using that method it should be petrol exhaust.

Pay the money.
To solder it must be super clean.
Most of the people who do radiator and fuel tank repairs have a sand blaster.
To do a good job you need the special solder the radiator repairers use.
Normal hardware solder will not cut it.

If you wish to purge the tank of fumes and braze weld, which is much stronger and lasting than tin solder, this is what I've been doing for 50 years.
Build a fire and place a 20 litre drum or bigger on the fire and get some steam going. Run a hose from the steam drum to the tank and steam for several hours, have the tank setup so that water can run out.
After steaming fill tank to within an inch of the surface to be welded/Brazed and away you go, good luck.
Or you could hire a steam cleaner, but that would cost as much as getting a pro to weld it, Regards Frank.

I've welded many petrol tanks. Once completely empty, leave it out in the sun for a couple of days with the senders out. Blow some compressed air into one of the holes and take a lungful of air at one of the other holes, if it's sweet air just go and weld/braze/whatever. You can purge with petrol engine exhaust too but under no account would I fill the tank with water after all that effort. Steam doesn't do weld any good at all.

As for the stage one tank, I had to repair one once. The local radiator man got the soldering job as my skill is limited. It cost me about $50 as I had done all the prep work already. I also cut the fuel filler pipe and added a rubber sleeve and two clamps, as I could see the tank neck would probably crack out again with its long tube and the vibration.

Welded a few tanks over the years and used a similar technique to bee Utey but cleaned it with water and detergent first, then left out in the sun for a few days to completely dry out. Before starting any welding, I would hide behind the big steel work bench in my mates workshop and reach over with the oxy and give it a quick lick of a nice hot flame..... Never had a bang and I'm still here to tell the tale...