G'day guys, i need to do some repairs to an old fuel tank and i'm after some suggestions on how to go about cleaning/preparing it so I don't blow off any limbs etc.
Anyone have any tested methods? i'm only going to be pin-pulling the damaged areas (i'm not cutting it in half etc), i've done a bit of reading here and there, some suggest washing it in dish soap others suggest doing the welding with the tank full of water, others say connect it to an exhaust of a car to fill it with carbon monoxide.
Is there places that chemically clean tanks so they're safe?
Cleaning a fuel tank for welding
Started by
_Pete_
, Apr 16 2006 11:28 PM
31 replies to this topic
#2
_jap-xu1_
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Posted 16 April 2006 - 11:33 PM
ive done it and all i did was air it out for a day, give it a good hose down and weld away.
#3
rodomo
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Posted 17 April 2006 - 12:05 AM
Filling it totaly with water should expel all fumes and as fuel is lighter than water all fuel too. Then empty it and dry it out. I hope this gives you piece of mind thrill seeker. 
#4
warrenm
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Posted 17 April 2006 - 06:57 AM
Fill the tank with "Caustic Soda" & water,leave it over night then empty solution out,should be nice & clean to do your repairs.Caustic Soda should be available from supermarket or hardware store.
#5
racean69
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Posted 17 April 2006 - 07:53 AM
Wash out with water then and fill with water while welding and make sure tank is vented.
#6
lakeside
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Lotsa Posts!
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Posted 17 April 2006 - 08:54 AM
My wife told me a few years ago. Her dads, best mate died welding a fuel tank, it hadn't had petol in it for 10+yrs.
Edited by lakeside, 17 April 2006 - 08:55 AM.
#7
_jap-xu1_
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Posted 17 April 2006 - 09:18 AM
welding around a large body of water is not safe practise
#8
makka
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Posted 17 April 2006 - 10:21 AM
just get it steam cleaned or solder up the holes
#9
FastEHHolden
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Posted 17 April 2006 - 10:36 AM
WTF?
We welded a diesel tank not 2 weeks ago....filled it with water but it draws too much heat out of the weld.
I think the best way is to fill it with CO2.
reason for explosions after many years is that fuel sits in the folded seams of the tank.
We welded a diesel tank not 2 weeks ago....filled it with water but it draws too much heat out of the weld.
I think the best way is to fill it with CO2.
reason for explosions after many years is that fuel sits in the folded seams of the tank.
#10
_CHOPPER_
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Posted 17 April 2006 - 12:28 PM
Get somebody else to do it. And don't hang around and wait.
#11
_Pete_
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Posted 17 April 2006 - 01:26 PM
thanks for all the suggestions, so far ive flushed the tank out with car wash and dish soap approx 6 seperate times including clean flushing with water. The good part is I dont need to weld holes or splits up I only need to use an air operated pin puller to pull out the dents. This works by using the tool to weld the tip of the tool to the job and then it uses air to pull back and twist pulling out the dent and breaking the weld. Considering the weld is really only on the surface and not penetrating the steel like a normal weld would im hoping it should be plenty safe as the steel it welds to doesnt even get red hot at all when using it. I'm mainly worried any fuel varnish left on the inside of the tank might ignite but i think if i fill it with water i'd hope it should be fine.
#12
_gtr-xu1_
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Posted 17 April 2006 - 01:54 PM
get someone you dont like to weld it for you HA HA HA Ha 
#13
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Posted 17 April 2006 - 03:15 PM
I welded a fuel tank just the other day, rinsed out with water then put it over the exhaust pipe of a running car for 20-30 min. (so exhaust can run through it).
Never had a problem and have done it numerous times.
Never had a problem and have done it numerous times.
#14
shanegtr
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Posted 17 April 2006 - 03:18 PM
If you have a mig gas bottle then seal the filler up with tape and stick the gas hose into it. Let it purge for say 5 mins, and then keep a small flow of gas into the tank. It cant explode if its got no oxygen in it. In fact it would work with any gas that has no oxygen, exept flammable gases, which will be safe from exploding inside the tank, but the vent where the execess is coming out wont be
#15
_smelvin_
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Posted 17 April 2006 - 05:58 PM
As shanegtr says, purge the tank. Any inert gas will do this, pure argon, argoshield, nitrogen. Purging expels oxygen if done right, and without oxygen you get no explosion. To purge, you use an inert gas that is heavier than regular air, fill your tank from the bottom and have a vent at the top and have a constant flow, 5-6 litres/ minute will do. Have heard of water, soapy water and exhaust fumes and these may work but most welders that want to live to give the Torana to their grandchildren will purge the tank. 
#16
LS1LX
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Posted 17 April 2006 - 06:29 PM
Seen the price of fuel lately, its cheaper to get the tank flushed then run a car for 1/2 an hour.I welded a fuel tank just the other day, rinsed out with water then put it over the exhaust pipe of a running car for 20-30 min. (so exhaust can run through it).
Never had a problem and have done it numerous times.
I recommend getting the tank flushed by a radiator mob, for 3 reasons.
1 its cheap
2 they remove all the dirt and shit thats been sitting in the tank the last 30 years
3 whats your life worth $100 for a flush or less?
I keep saying this, with cars theres 2 things you dont skimp out or mess around with, FUEL and BRAKES, do them right and forget about the cost, these 2 MAJOR things are carrying your life.
#17
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Posted 17 April 2006 - 06:40 PM
Agree entirely with LS1LX ^, re leaving fuel and brakes to the experts, the consequences of getting it wrong arent worth the saved money.
Just my 10cents worth here. People may have done/tried various things, however, the fact that they are here writing up their method on the forum is no guarantee that the method is safe, though I�m not claiming any of the above techniques are dangerous.
Personally, I�d be getting someone else to do the work as I am simply not sure of the possibilities that could occur.
I believe welding does take place on petrol tankers etc, would be good to find out for sure what methods are used.
Here are just some thoughts/comments on the suggestions so far:
MIG bottle? The IG, loosely stands for Inert Gases, however, using them beyond their intended use... as fire extinguishers etc could be asking for trouble. The composition of what's in the bottle should be established 1st. The gases vary depending on application, up to 4% O2 in some cases. 4% is "probably" going to remove the chance of combustion, but wouldn�t be the best thing to be using.
Using commercial grade CO2 would be effective, heavier than O2 and would be the cheapest available oxygen displacing non flammable gas (wont call it inert as it's not chemically inert). Argon would be an effective inert gas to use, but expensive.
Running the engine exhaust through it while you are doing it? Shouldn�t be much oxygen there, but heating it will vaporise what ever fuel has embedded it from the seals etc.
Large flow of air through tank (for an hour or so and while doing the welding might be safe) after emptying and rinsing with deter and water would be ok if no CO2 available ie sticking a leaf blower into the filler).
Just my 10cents worth here. People may have done/tried various things, however, the fact that they are here writing up their method on the forum is no guarantee that the method is safe, though I�m not claiming any of the above techniques are dangerous.
Personally, I�d be getting someone else to do the work as I am simply not sure of the possibilities that could occur.
I believe welding does take place on petrol tankers etc, would be good to find out for sure what methods are used.
Here are just some thoughts/comments on the suggestions so far:
MIG bottle? The IG, loosely stands for Inert Gases, however, using them beyond their intended use... as fire extinguishers etc could be asking for trouble. The composition of what's in the bottle should be established 1st. The gases vary depending on application, up to 4% O2 in some cases. 4% is "probably" going to remove the chance of combustion, but wouldn�t be the best thing to be using.
Using commercial grade CO2 would be effective, heavier than O2 and would be the cheapest available oxygen displacing non flammable gas (wont call it inert as it's not chemically inert). Argon would be an effective inert gas to use, but expensive.
Running the engine exhaust through it while you are doing it? Shouldn�t be much oxygen there, but heating it will vaporise what ever fuel has embedded it from the seals etc.
Large flow of air through tank (for an hour or so and while doing the welding might be safe) after emptying and rinsing with deter and water would be ok if no CO2 available ie sticking a leaf blower into the filler).
Edited by devilsadvocate, 17 April 2006 - 06:45 PM.
#18
_smelvin_
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Posted 17 April 2006 - 07:05 PM
I am a professional, eg. I take your money to weld. Nitrogen is most cost effective purging gas, but as with most things in life, you can not get all my years of engineering experience from a forum. If in doubt, pay someone to do it for you. 
#19
_torana_
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Posted 17 April 2006 - 07:25 PM
buy a second hank tank from the wreckers, or ebay ( and maybe sell your dinted one )
I know i wouldnt be risking my life for a $100 bucks ( or whatever it costs to buy a second hand tank)
cheers julian
I know i wouldnt be risking my life for a $100 bucks ( or whatever it costs to buy a second hand tank)
cheers julian
#20
FastEHHolden
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Posted 17 April 2006 - 08:51 PM
he isn't risking his life with that machine.
#21
_Pete_
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Posted 17 April 2006 - 10:08 PM
but as with most things in life, you can not get all my years of engineering experience from a forum. If in doubt, pay someone to do it for you.
You've obviously just finished reading the book "How to win friends and influence people" hey smelvin?...hehe....i'll keep an eye for any of your posts when there's something your interested in finding out and I may be able to help out with
buy a second hank tank from the wreckers
I'm not repairing a torana fuel tank here, and unfortunately there has never been a time in history where you can buy these fuel tanks from your local wrecker.
Like FastEH has said the pin-pulling machine I'll be using isnt like a mig etc where i'll be penetrating the steel, all this does it use the smallest of tacks to pull the dent out and in the same motion it unpicks the weld. I'm confident that I'm taking the necessary precautions I just thought i'd ask for suggestions in case someone had a method that i hadn't heard of.
Thanks guys, except smelvin.....hahahaha
#22
_munro_
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Posted 20 April 2006 - 01:05 AM
just put a match to it
if it has petrol fumes no more dent in the tank 
if it doesn't then you'll have to do some work
tom
if it has petrol fumes no more dent in the tank
if it doesn't then you'll have to do some work
tom
#23
_CHOPPER_
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Posted 20 April 2006 - 07:06 PM
Are you going to video how to do it Tom?
#24
_dave720gtr_
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Posted 20 April 2006 - 07:32 PM
SMELVINI am a professional, eg. I take your money to weld. Nitrogen is most cost effective purging gas, but as with most things in life, you can not get all my years of engineering experience from a forum. If in doubt, pay someone to do it for you.
this is the way its done^^^^^^^^^purg with mig gas or noz is good to
#25
shanegtr
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Posted 21 April 2006 - 02:24 AM
The lower explosive limit of petrol fumes (LEL) is 1.4% by volume and the upper explosive limit (UEL) is 7.6%. This means that in a fuel tank, the percentage of petrol fumes need to be within those two %ages to cause an explosion
The LEL for diesel fuel is typically 3.5% by volume and the UEL is 6.9%; ie, a higher LEL and a smaller range than petrol
So both are quite limited when you really look at it
The LEL for diesel fuel is typically 3.5% by volume and the UEL is 6.9%; ie, a higher LEL and a smaller range than petrol
So both are quite limited when you really look at it
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