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How would you fix a gas tank puncture?


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14 replies to this topic

#1 NanoSoob

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Posted 16 November 2003 - 12:58 AM

Although this happened to my new-gen Soob, I'm posting this here in hopes that more people will have experienced similar problems and come up with creative solutions.

I managed to punch about a two inch long gash in the bottom of my fuel tank in my 95 Impreza LX.
Before I attempt to repair it (replacing it really isn't an option due to current lack of funds) I wanted to see what the concensus was on how to properly repair a tank.
The tank is metal, so welding would probably work... But I only have access to an arc welder currently (I may be able to access a MIG welder in the near future).
I've talked to a couple of experienced car guys and they both say that they wouldn't weld it. One says to patch it with fiberglass and resin, the other suggested using a plate to bolt over the gash and seal it with silicone.

I'm looking to get a good number of years out of this car still, and I would like the tank repair to last the winter at the very least.
What would you recommend?

#2 GeneralDisorder

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Posted 16 November 2003 - 01:02 AM

Indeed they can be welded - I have a welder friend, and I spoke to him about this very thing once. He said he used to do it all the time back in the day. There is some specific chemical they pour into the tank to nuetralize the gas vapor so as not to cause an explosion. I can't recall what he said they use... but maybe a little google searching could find that info....

He was also not very optimiztic about being able to get that chemical - it might be something that is controlled these days. Like mercury is now. But maybe they have something new that does the same job....

GD

#3 torxxx

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Posted 16 November 2003 - 01:22 AM

The chemical General is reffering to is called purge fluid.. We use it in our chainsaws to neutralize the gas vapors, if we have to get flown somewhere in a helicopter..

#4 AK-Brando

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Posted 16 November 2003 - 01:37 AM

A friend of mine had an old Bronco that had a bad tank in it. He used a product called Z-spar to make a patch. It would hold for a while then start to leak again. His Bronco was what we call a "Kodiak Klunker". Basically it was a beater that was more rust than solid metal!

Z-spar is a two part epoxy that can be used for all kinds of repairs. I have used it on commercial fishing boats for various repairs, but never for a gas tank.

I have also repaired a gas tank on a lawn mower with JB Weld. However that tank was quite a bit smaller than the tank in your car! :D I don't know if JB Weld would hold up to the pressure of an automobile tank. It worked fine on the lawn mower tank and never leaked again! I just made sure I had the surfaces very clean and roughed them up well before bonding them together.

Good Luck!

#5 Turbone

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Posted 16 November 2003 - 01:58 AM

I have some stuff in my shed, made just for sealing gas tanks. I'll see if I can find it tomorrow.
Rob

#6 TomRhere

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Posted 16 November 2003 - 07:07 AM

May want to check some of the Radiator repair shops around your area, some of those places will do gas tank repair also.

I have used a product called Seal-All. Comes in a yellow and red tube with black writing. Got the last tube I bought at Wal-mart.
This stuff is good for tank repairs, and will stop a flowing leak. I've used it by itself to plug holes upto 3/16", used a sheetmetal screw or bolt in the bigger holes to help plug them.
A 2" gash is a rather large hole to patch over. If you can get hold of an air drill, you could cover the gash with a patch of sheetmetal, then use the Seal-All over it .

Please be mindful of what you are working on. You don't want excess heat, or sparks near a gas tank that has a hole in it.
I have dropped afew tanks, and put a garden hose in the filler hole, filled the tank with water, then done repairs to it. This will reduce the amount of vapors in the tank. Less likely to go BOOM that way!!!

#7 e3mt

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Posted 16 November 2003 - 08:55 AM

Plugged a hole about that size with that 2 part epoxy type stuff. The kind that comes with two rolls of clay-like material (one was gray and the other black in color).
The "repair" lasted a little more than one year before it fell out.
I recommend a proper repair before you resort to this one.

Regards - Mark

#8 demmer

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Posted 16 November 2003 - 10:35 AM

We use a sealant called Pro-Seal in the aircraft industry to seal fuel tanks that we build. You can buy it from Aircraft Spruce and speciality. I would cut an overlay matching material, drill and cleco in place then when ready pro seal the patch and rivet it in place. Hope that helps.
Shane

#9 j.szigi

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Posted 16 November 2003 - 10:54 AM

a bar of soap, aka irish springs or the like is supposed to do wonders. just open it up out of the package, while gas is still leaking, just rub it on and over and over. the gas with the contents of the the soap are supposed to transform via some type of chemical reaction and form a bond that is lasting. i personally have not tried it but have simply read about it in a survival type manual for vehicles in the woods.

#10 NanoSoob

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Posted 16 November 2003 - 11:32 AM

Wow, lots of good suggestions! A big thank you to everyone who has contributed!

I'm not certain that I will be able to borrow an air drill, which would seriously hamper any repair method that requires a piece of metal to be screwed over the hole.

I have some west system epoxy and fiberglass which could be used on the hole. I also have POR-15, which I have used like epoxy (with fiberglass) in the past to repair rusted sections of metal. Any thoughts on the POR-15 versus the epoxy?

It sounds as though if I want the tank repaired permanently I should either get it welded or buy a new one. And if I want the repair to just last the winter I could try some epoxy.
If I could get a patch over the hole and used Pro-Seal or something similar how long could I expect that repair to last? I don't drive this car off road, it's basically my commuter vehicle, so there shouldn't be any sudden stresses to the tank (from hitting it on a rock, tree branch, etc.).

Thanks again for all your help!
NanoSoob

#11 demmer

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Posted 16 November 2003 - 11:51 AM

Pro seal if applied properly will last years. Most experimental airplane tanks are sealed with it and are successful. Only use current proseal as it has an expiration date. You can extend it's life by putting it in the fridge but the best practice is to use it while it is current. Be sure to prepare the surface first per directions. Good luck.
Shane

#12 Turbone

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Posted 16 November 2003 - 01:17 PM

The stuff that TomR was talking about is what I have. Works pretty well on the smaller stuff.
Have you considered another tank?
Rob

#13 Nug

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Posted 16 November 2003 - 02:46 PM

I've taken a vacuum cleaner and put it on "blow" and let it blow in there for hours. The heat from the motor and the airflow do a good job of evaporating all the gas and purging vapors. Then you can fill it almost full of water and weld her rump roast up. Or take it to a radiator shop. Or go to a junkyard and haggle for another.

#14 eyesore

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Posted 16 November 2003 - 06:39 PM

JB Weld will not hold more than a week. As soon as the tank builds some good pressure, PoP! Out comes the plug.

The soap trick does work, but it is a temporary / trail fix only. The soap plugs the hole and the gasoline does not dissolve soap the way water does, so the plug holds. No fancy chemical reaction, and a 2" gash is way more than the soap could handle. It is a handy tool to keep in the car though, just in case! ( I have found Ivory soap works best....)

#15 burden2

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Posted 16 November 2003 - 09:41 PM

If you do have to go down the road of welding your gas tank - avoid if possible - here is a quick easy purge method that works in a pinch and costs nothing but a bit of time.
Take out the tank and empty any gas out. Using a garden hose give it a flush out for a while, until the sheen isnt coming out on the water is a good indication that all the loose gas is out. Sit it on a saw stool or workbench with the filler facing down. Using a decent sized hose pushed into the filler neck and taped on-leave a small gap between the hose and the neck- connect the hose to the exhaust of another vehicle-diesel would be best but petrol engines produce carbon monoxide too! Start the vehicle and leave it idling for a while, 10 - 15 mins should be ample. The exhaust gas is basically an inert gas purge and even if there are fumes still in the tank it will be enough to prevent them exploding. You can keep the car running while you weld the hole but you will need to remove any tape you use on the hose as it will quickly pressurise and blow the hose out once the hole is closed by the patch. AND KEEP YOURSELF WELL VENTILATED!!!
Another method if you have to gas weld it is to flush then fill the tank with water until it is almost at the level of the repair, this minimises the volume that can hold fumes and reduces any chance of explosion. Not so good if you are using electric welding but for the old flame jobs its perfect! All you need to watch is your heat, the water does absorb a hell of a lot of heat so to get a good weld you will need to jazz up the flame a bit.
If you need to weld in a patch try to cut one that you can fit to the inside of the hole and weld it from the outside, it will make sure that the patch is welded to the skin of the tank and wont leave edges that will rust out over time.

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