how do you weld on a gas tank without an explosion?

[Todd]

I would go with epoxy as well

 

[pocket-rocket]

I had an old 83 Honda Prelude that had a tank leak almost half way down. I bought some JB way back before they had the sticks. Cleaned the coating off the tank with a screwdriver! being young and dumb at the time and it held fine until the poor car stopped running despite incorrect prep work.

 

[rboyer]

I did some "experiments" with a couple of junk steel fuel tanks that I had before and I found that even after flushing them out with water several times they still detonated when I exposed them to open flame. The one smaller tank with smaller openings on it actually bloated out into a big ball. I tried this out on junk tanks because I needed to weld one and when I actually did it I ended up just filling it with water almost all the way to the top and didn't have any problems.

 

[RedRanger888]

I did some "experiments" with a couple of junk steel fuel tanks that I had before and I found that even after flushing them out with water several times they still detonated when I exposed them to open flame. The one smaller tank with smaller openings on it actually bloated out into a big ball. I tried this out on junk tanks because I needed to weld one and when I actually did it I ended up just filling it with water almost all the way to the top and didn't have any problems.

IIRC, even after rinsing a couple times, there will still be petroleum residue, which will keep releasing fumes. That's why, as previously mentioned, it is VERY important to fill the tank with some form of non-flammable gas, like argon, carbon monoxide (exhaust), etc. As far as welding, or cutting, on galvanized stuff, do it in a well ventilated area, that stuff can mess you up!

 

[blue83ranger]

i've never had any luck with JB weld and gas tanks. I've seen the stick stuff used on a transmission pan with good results. It was in a demo and we needed a quick fix.

 

[wisconsinjimmy]

I might have missed it but CO2 which you can get at any welding shop, but the safest way is to toss it and get a new or newer tank, odds are if the tank rotted thru then the inside is in tuff shape. Be smart and work safe not dumb and crippled up just to save a buck.

 

[AllanD]

IIRC, even after rinsing a couple times, there will still be petroleum residue, which will keep releasing fumes. That's why, as previously mentioned, it is VERY important to fill the tank with some form of non-flammable gas, like argon, carbon monoxide (exhaust), etc. As far as welding, or cutting, on galvanized stuff, do it in a well ventilated area, that stuff can mess you up!

Carbon Monoxide is a terrible choice because it is itself a flammible gas. I use Carbon Dioxide
which has the additional benefit of not only being heavier than air,
a normal component of shielding gas, but it's also heavier than
gasoline fumes.

I have welded a tank that still had liquid fuel in it, but it also had a
constant flow of CO2 into the tank while we were working.

I have also used C25 "Mig Mix" and pure Argon.

AD

 

[projectnitemare]

Heck I dump the tank out and let it air out for a few hours, toss a match at it and poof. Weld away. Maybe I'm on a mission of sorts...who knows.

Matt

 

[Mac]

I just jet the garden hose purge it for a couple of hours and then let it sit overnight filled with water. Didn't weld the holes but solder the holes, guy who did it ran a welding service and that's what he reccomemded.
Dave

 

[falcon57]

Wash- fill with sand- weld..

 

[TrucksGetDirty]

My gas tank is plastic? lol

 

[Will]

If you didn't have luck with JB Weld you just didn't prep it. It's important to use a strong solvent to ensure it's totally clean. I used JB Weld to glue on 2 plates to cover EGRs on aftermarket aluminum intake manifolds--no fasteners and no failures. I also used it to fill exhaust port air injection port holes. And I even built up an exhaust valve seat after my VW lost a keeper and swallowed a valve and it ran for a couple of weeks with spare parts in it while I found a donor engine. With good prep, that stuff is incredible.

The epoxy dough sticks have been around since I can remember. The are not as good as JB Weld because they don't flow into the repair, but you can use them upside down and if it's just a gas tank, it's not holding back much pressure.

 

[AllanD]

Because I dislike rust holes both (the third tank is another discussion) of my tanks are plastic.

BTW, there is actually very little carbon monoxide in engine exhaust
modern cars make under 1% CO, the bulk of the exhaust is CO2 and
water vapor.

Most people don't think through the effects of burning a HYDROcarbon
and can't figuire out where the water comes from (LOL)

AD

 

[blue83ranger]

just thought i'd update everyone, 1st i didn't blow up and i did weld it. I had the tank out and empty before i started this topic. Filled it twice with water and I had it empty when i welded it. There was no hint of a flame anywhere. It worked great no problems and no leaks. I did have something totally confuse me though, see if you can figure this one out. I drug either an '83 or '84 ranger parts truck out of our woods to see what shape the sending unit was in because the gauge part of mine went bad. so i got the tank out and 1st the electrical plug was different and rusted off but i took it out anyway and the tank was 1/2 full of gas yet. and we got the truck more than 10 years ago and there was NO rust anywhere in the tank. Not even any crust, gunk, or gu. and the gas didn't really even smell bad. Can anyone explain how that was possible? i know leaded gas (assuming it was leaded) lasts alittle longer but over 10 years!!! I put some in my Farmall B and it ran like the stuff was just bought.