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whats the safest way to welf aluminum fuel tank?

Posted: Mon Feb 01, 2016 11:26 pm
by Hog Guts
still smells like gas in there but we siphoned all we could get out. 80 gal tank maybe three sections two baffles. was leaking fuel slowly through a few corrosion spots on bottom. fill it with water? hook to truck exhaust? or what? i have seen guys weld aluminum tank before with a little fuel in there that are career welders but i backed up and im still a pansy when it comes to welding fuel tank with gas fumes coming out still... whats the best way to tackle this chore?

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 2:38 am
by jchovernut
It takes very little fuel for the vapors to be explosive!! Are you able to remove the tank? I'd suggest some sort of detergent wash, & dry.
If in-situ, then try to suck out as much fuel as possible with a tygon hose & purge the crap out of the tank with air supplied by hose deep into the tank. A vigorous purge or Nitrogen inerting during the weld would be good measure. I base this off what I've seen shipyard welders do when I was in the Navy, & the "Confined Space" certification authority I held at the time.

Good luck!!

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 3:36 am
by digginfool
If you smell vapors, you are risking your life. A mechanic that used to work for me nearly killed himself welding on a 110 gallon Diesel fuel tank that had a small split in it from an unsecured tool rolling into it in the back of a pickup truck. He washed the tank with soap and water, sprayed it out thoroughly then touched the Mig gun to the hole. The explosion blew ceiling tiles out of my office and shook the entire 18,000 sq ft building. When I ran out to the shop, he was standing there with seared skin dripping from his arms and back. The sad thing was, we had a cylinder of Argon that he could have purged the tank with but he thought that since it was just a little smell, he would be safe. Dude, I'm telling you, if you don't know what you're doing, don't mess with it. Take the tank to someone who knows. Not worth dying over a hundred bucks or so.

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 5:57 am
by Shippee123
X2 !!
Saw a deisel tank go through the roof of shop I worked at . Purged and was using exhaust , wasn't a strong enough concentration I guess . Not worth it !

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 7:11 am
by radtech
If you have time, you can leave the tank open for a week or so and let it evaporate. Definitely wouldn't weld it if you can smell gas

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 7:22 am
by glades cat
Some years ago, Sept 2009, we got a rescue call to an old gas station where the fuel tanks had been taken out and were sitting on the ground. The tanks had been out of use and empty for years, more than a decade. This guy/patient was cutting the end open with a sawzall and had made most of the cut....and the tank exploded. He had made a few cuts to the tanks already. It ripped his left leg completely off and shook the neighborhood. The trauma was so severe we couldn't save him. I posted a few pics in the gallery without the gory mess.
Take it to a professional welder who has knowledge and experience working on fuel tanks previously in service. There is a safe process to do this.

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 7:36 am
by skinnypockets
When I was young and invincible I welded a few gas tanks with good results. I won't say how I did it because I wouldn't want to be responsible for someone getting blown up.
You can ask Gerald, (newoldglory), how well filling it with water works if you are looking for excitement, I'll bet he will tell you not to try it!

Is the corrosion on the outside or the inside? If they are small places on the outside it can be repaired with epoxy. If you cannot see the inside, the damage may likely
be more extensive than you think so when you repair one spot another may show up in a few months. Better to invest in a new tank!

Remember "AIRBOAT" , (ANYTIME IT RUNS, BREAK OUT ANOTHER THOUSAND) :(

:rebel: :florida: :old_glory:

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 7:50 am
by skinnypockets
Reminds me of a story I heard one time about a dog crossing a railroad track. A train was coming and he thought he had time to make it across, after all he had done it many times and never had a problem. Well he wasn't as fast as he once was and almost made it but the train cut off the end of his tail. He didn't want to lose it so he instinctively turned around to grab it and the train cut off his head. Can you see the moral of the story? :rebel: :florida: :old_glory:






moral-- :slap: (Don't lose your head over a little piece of tail!) :violent1:

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 8:00 am
by skinnypockets
radtech wrote:If you have time, you can leave the tank open for a week or so and let it evaporate. Definitely wouldn't weld it if you can smell gas



Here you go, I think radtech just volunteered to weld it for you! :lol:

radtech, Read my last post. :toothy7:
:rebel: :florida: :old_glory:

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 9:21 am
by Afflicted
I wouldn't weld a GAS tank. I've reluctantly welded a few diesel tanks from log trucks but they wer washed out the purged purged purged with argon

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 9:31 am
by 12PSI
You have a 80 gallon fuel tank in your boat?

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 10:09 am
by Deano
I am curious about the 'water incident'. Let's first presume a properly cleaned, vented and dried tank. Beyond that . . .

Obviously, you wouldn't want to fill it 90% full and then weld on the top of it after concentrating any remaining contents at the top of the tank. But, I have seen this approach employed when welding below the water line so to speak, and it looked (to this casual observer) to be a reasonable tactic in that circumstance.

I am curious about this though, as I would readily share this information if/when I see someone fixin' to do this since that would be more sporting than simply helping to clean up the mess.

So come on Gerald, give us the Skinny about the water fill gone bad. Mr. Pockets put the ball in your court. :D

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 10:43 am
by Scarecrow
I have welded a few tanks by washing out good then tape off openings, then run an argon line in the tank while welding. But if you are asking for the safest way then take it to an expert. :thumbleft: :rebel:

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 10:48 am
by John Fenner
80 gallons? I would start with 2.5 gallons of degreaser of choice. Slosh this around the whole tank in every way possible, then hit it with the water hose with high pressure to suds it up good till full. Drain it off, rinse and repeat same steps again. Take a shop vac to it with other vents and ports open and draw as much moisture out as possible.
Once dried out, sniff test works for me, no fuel odors, weld away. Done this multiple times.

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 11:01 am
by Afflicted
Idk if it makes much difference but argon is heavier than air and the few tanks I welded, I put the argon hose in at the bottom so it would "push" the air out the top

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 11:53 am
by CactusJack
What a bunch of sooks.... I thought you yanks were tuff? :stirpot: the tank will have to come out of the boat to get at the bottom of it, so get what you can out of it by tipping it out thru the filler and line pipes until you cant hear any left, then leave it open for a few days.... then blow it out with compressed air or a shop vac that can blow air.....then sniff.... when you can hardly smell any gas, if you have argon or C02/argon... or truck exhaust... purge what is left for a few minutes... then with a barbeque lighter (long flexi lighter) or oxy acetylene flame.... wave it around the hole.... it is no more likely to go bang than if you lit a fag in the thunderbox! (a cigarette in the toilet) :lol: .... I have welded 44 gal drums that have stored avgas like that.... I have even retired old drums that wont be holding gas any more and just waved the torch over the open bigger hole and watched the light show.... it is very entertaining at night....

gas needs the right mixture to 'blow up' that being 13 or 15 to one ratio... if it aint at that ratio, it wont burn.... if you have the tiniest last fumes in it after purging... waving the oxy near the opening will make sure it wont go pop and make you mess in your pants whilst welding it :lol:

Anyway, why weld? Why not get some of that liquid gas tank repair liner stuff? It comes as a kit, it coats the inside of the tank.... the price on my pic is Aussie $, so in the US it would be heaps cheaper....

You have to be sensible... but it is when people take no precautions and still have alot of gas left in the tank.... they have issues... go get a soda can and put a little gas in it, then light it with a long lighter.... it goes woof, then burns like a candle until the gas runs out.... it is the 'woof' you don't want to get caught in... so when you have aired and ventilated it... purged it.... put a flame near the opening and make it go woof in your terms... I bet you it wont if you think about what you are doing.... :wink: :D

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 12:33 pm
by skinnypockets
I can see Australia has red necks too! "HERE MATE, HOLD ME BEER AND WATCH THIS" :drunken: :stirpot:

:lol: :lol: :lol:

:rebel: :florida: :old_glory:

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 1:34 pm
by jopete
when my new gastank leaked, i brought it back to the welder.
i figured he's either fix it or blow up.

he fixed it. didn't blow up.

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 1:58 pm
by timmmyy
Im a welder and i will tell you how to fix your tank problem ,buy a new one its not worth you getting seriously hurt or killed .I have fix them before and there is alot of prep work involved before welding . The last one i did i charge the guy $200.00 ang 6 months later it was leaking somewhere else . He bought a new one thank god

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 2:03 pm
by Arcticshooter
The Aussie's comment about the tank sealer is a good option.
Tanks can be welded, but even I have seen the 3rd degree scars from a gent that tried to blow himself up this way.
Now, I am an experienced welder and I would use a Hotsy to clean the tank and use an Argon purge with a small opening left to bleed out the argon and the rest of the tank taped tight around that Argon hose.
Lots of welding shops won't even take the risk of welding on your tank.
I would pick up a kit from the guys that make POR-15, the rusty frame paint. They make an excellent kit to clean, etch and seal your fuel tank. I think the kit I bought was just over $100 and it's enough to do our 95gal aluminum tank and my motorcycle tank.
On another note, the use of exhaust fumes is a very faulty option. No guarantee that you aren't adding unburnt fuel and oxygen into the already present fuel vapors. Purging gasses should be "ONLY" inert gasses such as Argon, Nitrogen, Helium, CO2.
I'm not saying that people haven't survived some of the more "hold my beer" options over the years, but that sure isn't a horse that I am going to bet on!
Good luck, take the safe route and get a sealer kit...ZERO RISK!!

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 2:29 pm
by CactusJack
skinnypockets wrote:I can see Australia has red necks too! "HERE MATE, HOLD ME BEER AND WATCH THIS" :drunken: :stirpot:

:lol: :lol: :lol:

:rebel: :florida: :old_glory:


Too right Skinny.... :lol: Git 'er done mate.... She'll be right.... then we can crack a couple of tinnies and chuck some shrimps on the barby....

As long as we don't but a plugger...no worries mate :wink:


Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 3:14 pm
by Afflicted
^^^^ hahaha that was a pretty funny interview catusjack

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 4:03 pm
by Scarecrow
Sorry if I mislead you, I just re-read your post and I have no idea how to "welf" a gas tank. :lol: :P :rebel:

Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 4:14 pm
by scrambletown
Scarecrow wrote:Sorry if I mislead you, I just re-read your post and I have no idea how to "welf" a gas tank. :lol: :P :rebel:

:violent1: :violent1: :violent1: :violent1: :violent1: :violent1: :violent1: :violent1: :violent1: :violent1: :violent1:
:cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers:
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Re: whats the safest way to welf aluminum fuel tank?

Posted: Tue Feb 02, 2016 5:06 pm
by Ol Yeller
The way I would do it is to wash it out with soap the best I can. Then take a 20' pvc pipe with a lit rag soaked in lighter fluid, and put that fire in the hole. Let that fire find what ever fuel vapor is remaining and then you're good to go. You could also use a long rope and tree branch to lower fire into the tank if you want to be further away.