Thread: Welding fuel tanks

Originally Posted by 101 Ron

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.

Clearly you're a richer man than myself

What's the difference in solders? More tin content?

Originally Posted by Tank

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'm leaning towards brazing. Mostly as the MIG at work has a stainless reel in it.

Originally Posted by bee utey

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.

Leaving it in the sun for a few days might be the go. I just don't want it to flash out on me while i'm in the middle of it. In terms of the water, that's only to decrease the internal air space so if it does flash out, then it may only be 10L rather than 60L.

Originally Posted by bacicat

. Never had a bang and I'm still here to tell the tale...

I'm not scared it'll go bang. No amount of petrol will ever go bang unless it's compressed and i've got the sender out.

Thanks for the advice, guys

One trick I learnt while go round australia

I had a leak in my 90 fuel tank in Alice Springs and a chap welded it up.

He stuck a vacuum cleaner in the tank to suck out any fumes left while he welded which I thought was a good idea and tip.

Yes a difference in the Tin/Zinc content.
I am not rich either and know what I am doing with a soldering iron and Oxy.
The job is made much, much easier with solder purchased from someone in the radiator game.........usually comes in a coil or stick with a round cross section.
A sand blasted surface will greatly help the solder to stick and travel as the surface left is very clean and slightly rough.
You can do it with 60/40 hardware solder and just sanding back the surface by hand , but you have everything working against you and it is harder and time wasting.

I often braze fuel tanks .
I just fill them up with water to near as possible to the job.
I make certain any fumes have a large outlet to escape.......ie the filler tube or fuel pump hole.
Yes It will go bang, but if the pressure has somewhere to go and the area not covered by water is small it is no big deal.

welcome to the oh&s nightmare thread...

Originally Posted by Reads90

One trick I learnt while go round australia

I had a leak in my 90 fuel tank in Alice Springs and a chap welded it up.

He stuck a vacuum cleaner in the tank to suck out any fumes left while he welded which I thought was a good idea and tip.

I doubt very much if that is a good idea. A sparking brush motor in the air/fuel stream? No thanks.

Putting a vacuum cleaner hose on the other end of the vac to blow out the fumes is a much better idea and faaar less painful. Done it myself but I wouldn't trust an apprentice to do it as they'd always get it wrong after cleaning the floor. There'd have to be a dedicated sparkproof blower for this job.

Originally Posted by Reads90

He stuck a vacuum cleaner in the tank to suck out any fumes left while he welded which I thought was a good idea and tip.

Do you know how many sparks the brushes in a vacuum cleaner produce. Get the right (well wrong actually) fuel vapour to air mix rushing past the brushes and you would be in for quite a surprise.

Can't happen you say? - we hire out a lot of vacuum cleaners. More than one has been destroyed that way.

An engineer mate did better than that . Made a home made forge and used the vacuum to provide the blow, but put it on the wrong end didn't he.

Regards Philip A