Welding a gas tank!!??... how long to wait after draining?

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Model T Ford Forum: Forum 2014: Welding a gas tank!!??... how long to wait after draining?
Top of pagePrevious messageNext messageBottom of page Link to this message  By wes heustess on Monday, August 25, 2014 - 01:49 am:

so I noticed a crack at the out spout for of my gas tank. I have a small 110 wire feed. how long do I need to wait before attempting to weld it as to not blow myself up?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Monday, August 25, 2014 - 02:14 am:

Wes,
Till 1987 I did the repairs on the gas and fuel tanks myself. I drained the tank and filled it up with water and leave it for the night with the cap open in and under water. All the gas will come out. The repairs, the next morning, were done outside of the workshop. In October 1987 I had a accident, not during a gas tank repair, with 3rd degrees burns for about 25% of my body. During my visit in the hospital I met a man who repaired gas tanks about the same way I did but the last one blow up in his face. Since than I send the tanks to a firm that is specialized in repairing gas tanks.
You can use chemicals to try to repair and seal the tank but I have no good experience with it.

Just be careful and good luck

Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By Martin Vowell, Sylmar, CA on Monday, August 25, 2014 - 02:32 am:

I used a sealant and it worked well until ethanol became the standard for fuel, I have no idea whether the new ones work or not. I had to make a coctale of solvents to get it out of my tank. My problem wasn't a leak though it was just rust scale.

The repro tanks are pretty close to the originals. why not just spring for a new one? It's a lot safer than trying to weld your old one.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, August 25, 2014 - 02:58 am:

A tank can be empty for years and still have a little vapor in the creases that can go poof when the air mix is just right.

The key words here are: "the air mix just right". You'll only have to rinse with water for a couple of times if you introduce something inflammable without oxygen into the tank that keeps the air out, then no risk at all for explosion.

I soldered my tank just the other day with an open flame to the tank without fear - I took the tank out, rinsed it with water, backed up my daily driver to the garage port and connected an old vacuum cleaner hose from the exhaust to the tank opening. I did the work with the garage port open and the daily driver's engine running. With the tank full of exhaust gasses there were no chance for ignition.

I've tried to solder with a tank full or almost full of water, but there was no chance of getting the metal hot enough for soldering - the water led the heat away too fast.


Top of pagePrevious messageNext messageBottom of page Link to this message  By wes heustess on Monday, August 25, 2014 - 03:01 am:

what about jb weld


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier on Monday, August 25, 2014 - 06:23 am:

Use a large copper soldering iron and you won't have to worry about sparks or flame, it will hold heat for a long time. You don't want any flame near the tank. KGB


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Barchock on Monday, August 25, 2014 - 07:37 am:

You need to flush with and keep argon pumped into the tank as you weld it.

If you are asking and only have minimal gear, I would suggest taking it to a specialist. Most will charge a pittance and it will be done correctly without risk of shrapnel...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eubanks, Powell, TN on Monday, August 25, 2014 - 07:51 am:

The pros use dry ice to kill service station tanks when they cut on them with a torch. I use exhaust gas, put a hose from another can exhaust in the tank and let it run for about ten minutes and leave it running while I am flame repairing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jon Crane on Monday, August 25, 2014 - 07:56 am:

I am redoing a Model A gas tank. Does anybody have good information regarding tank sealants? The tank is rusted inside, have removed drained, power washed, sloshed acetone, refilled, drained and still getting rust grit. Some folks are suggesting a sealant, but there have been many horror stories regarding the new gas etc.
Does anyone have a solid recommendation?
Thank you


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Wrenn on Monday, August 25, 2014 - 08:03 am:

For all the more that a new gas tank costs from the vendors, the fact that any tank that's original is no doubt deteriorating in places inside you can't see, why not skip the chance for catastrophic failure and just buy a new one. I suspect that "Pete's" '12 Roadster PU is sending bits of crud to the carb, so when I pull his engine this fall for the off-season re-build, I'm putting in a new tank. JMHO


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Gruber- Spanaway, Wash. on Monday, August 25, 2014 - 08:13 am:

When I first got my '24 Tudor 15 yrs ago I bought a new tank so that would be one less thing to worry about.
WRONG!
That tank sprung a small leak about every year or two until I bought an original off Ebay.
I cleaned and used sealer on it and has worked fine for 5 yrs now.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, August 25, 2014 - 08:13 am:

Jon, do you have access to a cement mixer ? Put a counted number of sharp screws in the tank, wrap it with something protective since it's a visible Model A tank and put it in or fasten it to the mixer to rotate for some time. Count the screws as you pick them out of the now clean tank. Check for new leaks & fix them right with solder or weld with precautions as described above. The volatile alkali ingredients in today's gas makes me doubt all kinds of sealants - when the seal eventually fails you'll have no end of troubles.

Here's a thread with some inside info from a refinery employee, Donnie Brown, hinting alkali is the real problem with today's gas, ethanol may not be the only culprit: http://www.mtfca.com/discus/messages/411944/466716.html?1406945382


Top of pagePrevious messageNext messageBottom of page Link to this message  By G.R.Cheshire on Monday, August 25, 2014 - 08:35 am:

Professional shops that still weld fuel tanks are getting scarce the ones that are left flood the tank with nitrogen / helium / argon before welding and the gas has a constant flow through the tank. NOT RECOMMENDED FOR THE HOME HOBBYIST!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Walter Higgins on Monday, August 25, 2014 - 08:40 am:

Steam cleaning is really the ticket prior to doing any work on a tank. Done correctly, it eliminates the vapor problem and breaks down all the junk inside.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry Kramer on Monday, August 25, 2014 - 09:17 am:

To clean an old tank, we jack up a small tractor back wheel, add screws or bolts, strap it to the tractor wheel and let it run for a while. As for how long does the tank have to be empty to not be dangerous to weld, FOREVER! Follow the advice given above.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Val Soupios on Monday, August 25, 2014 - 09:49 am:

Attach a hose from the tail pipe of your car and stick the other end in your tank. The carbon monoxide will fill the tank and it can be welded. I do that a few times after the tank has been emptied and then I do the welding while the tank is being filled with carbon monoxide. Be sure to do it outside and make absolutely sure that the tank was drained, flushed with water completely and is filled with carbon monoxide. I was taught this by an old time welder who did it all the time. I don't know if anyone else has heard of this but I was told it was common practice back in the day when they fixed things rather than replacing them.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Monday, August 25, 2014 - 10:13 am:

Wes: You welding the tank has a couple issues to me. First one is weld contamination. The neck of your tank has been soldered. You will need to remove "all" traces of the solder or you will "never" get a good weld with the mig. That will include removing the neck and removing the solder between the tank and neck. That is really not practical. So you need to re-solder it. If you have not done much soldering you will probably just make it worse. As to open flame or spark around gas tanks. It can be done but you "need" to be sure of your procedures. Car exhaust will work for a purge of the tank, but I don.t use it, as a car that is missing or flooding can actually give a good air/fuel mixture to "blow up". Its not a common problem, but it can happen. Argon or Co-2 (from your mig if you use gas and hard wire) is a very good choice. Any inert gas will work. Just put the hose in the tank and turn the inert gas on, and weld away. Make sure you have plenty in the Argon or CO2 tank, so you will not run out while welding or soldering. I used to work in refineries as a Boilermaker welder. I have crawled inside confined space vessels that had thousands of gallons of gasoline in them in the morning and by afternoon was inside them with a torch and welding machine making repairs. Main thing is, If you are not "absolutely" sure of yourself, do not do it. As to sealers. I have used POR brand sealers dozens of times. It has never failed yet. The main thing is preparation. It must be cleaned first. The screws and tumbling method above is what I do if it is rusty inside. Then you "must" clean it with a good degreaser. Then you "must" etch the tank with an acid that also removes any remaining rust. POR sells both the degreaser and acid to use in a kit with the sealer. The acid etch is to make the sealer "bond" to the metal better. Paint bonds to an acidic surface and not to an alkali type surface. When doing the "sloshing" of the sealer, be prepared to spend at least four hours with the tank. You will need to keep moving the tank to different positions after pouring out the sloshing compound (sealer) it tends to sag and settle in the bottom. By moving it to different positions and looking inside you can get a good even coat and make sure the seams are all covered very well. Then wait the 72 hours it says wait. I wait a week before I use the tank. The sad thing is it cost about 1/2 to 3/4 the cost of a new tank to seal them. The problem with the new tanks is "leakers" It seems to be more of a problem with the new tanks these days, as I hear of it more often. I even seal the new tanks, and I also use it on rare tanks that I can not buy, or old tanks I want to keep the "patina" of the old tank. Good luck with the project ..


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, August 25, 2014 - 10:25 am:

You have two options to safely solder a gas tank;
1. Remove ALL the fuel "which on a old tank is almost impossible"
2. Remove ALL the oxygen, which is not too difficult.
I use the second method and yes I solder with a propane torch and still have all my eye brows


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Coiro on Monday, August 25, 2014 - 11:44 am:

You get to a certain age and the hairs on the back of your neck tell you when there's danger at hand and you need to stop what you're doing, pour a cup of coffee and reevaluate the situation. -For instance, I learned the hard way that house current should be recognized as the undisputed realm of professionals. -I also learned never to start a plumbing job on a Sunday or any evening. -And sometimes, the only safe answer is, "Oh, don't be ridiculous; you look fantastic in those jeans." -Like I said, you just sort of pick these things up along the way of life.

In that same way, when you said you were considering welding on a fuel tank, the mental alarm bells went off and Jim Croce's "You Don't Mess Around with Jim" started playing in my head. -Brother, you don't want to do this. -Either take the tank to a pro or buy a new one or sell the car and take up needlepoint, but do NOT, NOT, NOT weld on a used gas tank.


Top of pagePrevious messageNext messageBottom of page Link to this message  By charley shaver on Monday, August 25, 2014 - 11:59 am:

as far as soldering go I learned this trick from an old radiator man sand blast everything first even brass .sure works well on cast iron. charley. password again


Top of pagePrevious messageNext messageBottom of page Link to this message  By Henry Petrino in Modesto, CA on Monday, August 25, 2014 - 12:02 pm:

Bob,

You're sure right about paying attention to those hairs on the back of your neck. My worst experiences happened when I ignored them!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, August 25, 2014 - 12:06 pm:

Bob
I certainly agree with you in regards to timing of plumbing projects and in regards to the "jeans comment. I will beg to differ about the electrical as I am now in the midst of remedying a problem that a "professional" electrician left in my house (cross feeding the same circuit if you have two switches on at the same time).

I do agree that I am no fan of welding on a gas tank unless you are a really skilled weldor.

And if the person can't figure out how to accomplish my method then I will not post it here.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dick Fischer on Monday, August 25, 2014 - 12:06 pm:

I believe Wes' original question was "how long do I need to wait before .............?"

About 100 years should be safe enough. We'll all be gone by then and it won't matter.

Seriously, the hydrocarbon residue never really goes away. Rendering the fuel/air mixture down to a non-combustable ratio by use of water, carbon monoxide, argon, carbon dioxide, etc. all work if done properly. The key word here is PROPERLY. My policy is to take gas tanks to a professional. The fact that he's still alive says that he know's what he is doing.

Dick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Monday, August 25, 2014 - 02:19 pm:

Val, modern car engines put out almost no carbon monoxide. I know a 40 year old guy who tried to commit suicide with a friend when he they were 15 by running the family car in a closed garage. They were a little sick, but no brain damage like you get with CO.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Monday, August 25, 2014 - 03:39 pm:

Most Model T tanks are cheaper to replace than to have repaired professionally.

For all others: http://www.gastankrenu.com/index.htm

They did a great repair on my 1924 Buick gas tank.

It sure beats blowing yourself up.

I also like the old fashioned soldering iron suggestion someone made above.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eubanks, Powell, TN on Monday, August 25, 2014 - 05:29 pm:

Run a hose from another vehicle in it and fill it with exhaust fumes or drop a bunch of broken up dry ice in it both methods will expell the fumes in about 10 or 15 m. I posted this yesterday and somehow it has disappeared.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Val Soupios on Monday, August 25, 2014 - 06:42 pm:

That is good to know about the carbon monoxide. Next time I want to commit suicide I'll use one of my Model T's. Seriously, the concept is to remove the oxygen so there can't be any combustion. I wonder if the exhaust from a modern car does that without the carbon monoxide


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Monday, August 25, 2014 - 07:49 pm:

Good burning mixes carbon(gasoline) and oxygen in the perfect ratio to make carbon dioxide, CO2.


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier on Monday, August 25, 2014 - 10:10 pm:

Here's a tank I repaired awhile back, cut open, cleaned and re soldered baffles and filler neck. Easy and safe with a copper iron and good flux. KGB


Top of pagePrevious messageNext messageBottom of page Link to this message  By jeff cordes on Tuesday, August 26, 2014 - 12:18 pm:

I've always used brass to repair them when they are full of water. Repaired 2 that way last week. I remember one tank belched some water when the little bit of exposed tank I was welding ignited. It just spit some water out and I went on doing my repair.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Saturday, August 30, 2014 - 01:55 am:

Donnie Brown has some VERY good advice, listen to what he is saying. I've been welding for fifty years, and have learned a few things. He has said it well. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Saturday, August 30, 2014 - 09:55 am:

I used to work for a fork lift company that regularly welded gas tanks. After a small explosion (thankfully no one hurt seriously) they started a new policy of keeping them full of water while they welder (as Jeff mentioned above). We never had another incident. FWIW


Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie K Cordes on Saturday, August 30, 2014 - 10:23 am:

There was a story about a very good local welder in our rural area. He placed a fuel tank that had been empty a long time on the floor of his shop. He lite his torch, one leg on each side of the tank, and started to weld the tank. After the loud bang, he realized that the tank was no longer between his legs. It took off like a rocket. He was lucky, he was not hurt.
He would not work on fuel tanks after that happening.


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