new trick when soldering a gas tank?

Thorwon · 02-10-2009, 01:34 PM

I found a good way to clean gas tanks so they don't explode when you solder on them.
I pumped all the gas out with a old holley electric fuel pump I keep around for transferring fuel (I hate trying to cyphon gas). Then I removed the sending unit, next I dried it out with rags.
Next is the trick, I put my heat gun into the fill neck and let it run on low for about 15-20 min.
Then I turned it on high and let it run for about 10 min.
At that point I could not smell gas at all in the tank.(I could not hold the tank either)

Once I got the neck and other tubes out I cleaned them up with sand paper and scothbrite, retinned and reinstalled them. When I went to solder them I reheated the tank with the heat gun and the solder ran in great.
I just hope it holds.

**Bubba Ray** · 02-10-2009, 06:28 PM

Boom! Be careful!

**80cj** · 02-10-2009, 06:33 PM

With the heating elements in the heat gun and fumes still present in the tank I think you're pushing your luck.

black954 · 02-10-2009, 06:39 PM

or you can just purge it with argon from a tig torch or mig gun.....

**JeepHammer** · 02-10-2009, 07:16 PM

Ditto.
Inert gas works good.

Flush with MEK and neutralizer works also.

**Kenbo-Slice** · 02-10-2009, 07:19 PM

I was going to say "why not just use an inert gas" I guess I got beat to it.

**John Strenk** · 02-10-2009, 07:59 PM

I just filled mine with water when brazed mine. Maybe the brazing was hotter. You might not be able to do that with soldering.

Thorwon · 02-10-2009, 08:16 PM

Quote:

Originally Posted by black954

or you can just purge it with argon from a tig torch or mig gun.....

Well ya gotta have one of them there fancy contraptions before ya can do that.
I don't have that much shop. Mine is open sided (well ventilated) and cold in the winter.
So I use a little common sense a few improvised tools and ideas and I keep my vehicles running.

black954 · 02-10-2009, 08:26 PM

I don't have a fancy shop, just a regular garage. I'm sure there are some cool tools in your garage that I don't have in mine. I also work on my vehicles to keep them running?

**JeepHammer** · 02-10-2009, 09:38 PM

Quote:

Originally Posted by Thorwon

Well ya gotta have one of them there fancy contraptions before ya can do that.
I don't have that much shop. Mine is open sided (well ventilated) and cold in the winter.
So I use a little common sense a few improvised tools and ideas and I keep my vehicles running.

Not really.

We leaned out the exhaust on one vehicle, and directed the exhaust gasses into a fuel tank so we could braze it up at a race one time.

Took the lock ring off the sending unit so the exhaust gas could FLOW THROUGH and VENT, and it worked really well with the sending unit bobbling there as the pressure built up, lifted the sending unit and released...

Not sure I'd do it today, but 25 years ago when racing on a shoe string and a prayer it got us through the finals!

Fjguercio · 02-10-2009, 09:47 PM

Quote:

Originally Posted by Thorwon

I found a good way to clean gas tanks so they don't explode when you solder on them.
I pumped all the gas out with a old holley electric fuel pump I keep around for transferring fuel (I hate trying to cyphon gas). Then I removed the sending unit, next I dried it out with rags.
Next is the trick, I put my heat gun into the fill neck and let it run on low for about 15-20 min.
Then I turned it on high and let it run for about 10 min.
At that point I could not smell gas at all in the tank.(I could not hold the tank either)

Once I got the neck and other tubes out I cleaned them up with sand paper and scothbrite, retinned and reinstalled them. When I went to solder them I reheated the tank with the heat gun and the solder ran in great.
I just hope it holds.

I am not an expert on gas tanks....

I can offer the gas fumes or fumes in general can ignite MUCH easier than the liquid fuel. Since it is premixed with air it is ready for the explosion to be set off with the hot coils, a flake off the coils, or eaven a super small spark for the brushes used on motor. Consider your self one lucky fella!!!

My neighbor had a very old GTO gas tank and he wanted me to solder a new vent tube, 1/2" tube. There was no gas and we thought for some time. This could explode like yours could be quick and the metal would be shratnel? Very DANGEROUS. WE used a yard blower and about 15 ft of hose to remote the electric motor from fumes, hooked it up and let it go for almost an hour. This replacement tank was empty for yrs we think, but the fumes can be very dangerous.

I glad you are still with us.

Oakbluffjeeper · 02-10-2009, 11:44 PM

My friend owned a cycle shop and just hooked a hose to a car exhaust and ran in the tank while soldering.>

Eaallred · 02-11-2009, 10:12 AM

Exhaust pipe here too. Works great, and is virtually free. Just idle it for about 15-20 minutes through the tank and all the gas vapors will be completely gone.

Rumpeltiltskin · 02-12-2009, 10:49 PM

Danger!!!!!!!

1986cj · 02-13-2009, 11:16 AM

I remember about 25 years ago a friend and I tried to replace the under seat tank on his CJ5 with one out of a car that would run under both seats and we had ran water in an out of that tank for a few hours. We wanted to braze in a fitting in it for the gas line. Well we had taken it out to the side of the garage and stood it up with the filler neck pointing up and just passed the torch over the opening and boom!!!!!! God we were luckily we were around the corner of the garage. BIG lesson learned.