whitstella
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| posted on 17/12/11 at 12:45 PM |
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welding a fuel tank
hi just wondering what is the best method of welding a fuel tank???
there is on feul in the tabk it has now been drained of a day but still smells of petrol.
ideas please.
cheeers steve
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scootz
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| posted on 17/12/11 at 12:48 PM |
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I'd be sticking a hose in it and running it through with water for a good bit before I went anywhere near it with a welding torch!
It's Evolution Baby!
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cliftyhanger
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| posted on 17/12/11 at 12:50 PM |
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I really would be VERY careful with a tank, the pro's steam clean them for a fair while. I heard that sticking a car exhaust into the tank for a
bit can do the trick, I guess that is just steaming it though.
Tanks that have been emptied and left are explosive for some time. Measured in at least weeks.
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UncleFista
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| posted on 17/12/11 at 12:50 PM |
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I've heard of people sticking the filler over the exhaust pipe and running the engine for a while, to clear them out.
Then filling with water before welding.
No personal experience of it though..
Tony Bond / UncleFista
Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...
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britishtrident
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| posted on 17/12/11 at 12:51 PM |
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After washing it needs to be steamed out for at lest a couple of hours ----- a steam wallpaper stripper should provide enough steam.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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dave r
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| posted on 17/12/11 at 02:29 PM |
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i have one to weld as well
mines been sitting next to the wood burning stove in the workshop for the last 6 weeks.... hasnt blown up yet, so i guess it should be ok
I'd love to give my imaginary friend a great big hug,
but this jacket makes it impossible.
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t11
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| posted on 17/12/11 at 02:47 PM |
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re tank welding
Hi done this many time's all I've done is run a hose pipe through it for 1/2 hr or so with some washing up liquid and the dried it
out.........and no problems.........Gordon
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MakeEverything
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| posted on 17/12/11 at 03:26 PM |
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I would washitoutwithsoapy water and fill up to overflowing. This removes any vapour. Which iswhatwill cause any explosion. Then, once flushed it
should be safe to weld.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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britishtrident
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| posted on 17/12/11 at 04:40 PM |
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Washing out alone is not enough, petrol has the habit of lingering in seams and reapears when heated this can enough to give rise a mixture
within the explosive range, the lower explosive limit of typical pump petrol is is just over 1% by volume (ie. 1 part petrol vapour to 99 parts
air). Also The auto ignition temperature of petrol can be as low as 250c. Because there is not enough fuel present ignition at levels close to
the explosive limit usually result in a flash fire rather than a fully explosion --- remember the school chemistry demonstration of
hydrogen burning.
The hot work rule is Empty, then Wash, then Steam, then Ventilate.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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deltron63
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| posted on 17/12/11 at 04:42 PM |
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Put a pipe from your exhaust in to the tank and fill it full of fumes. Sounds daft but works !!
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blakep82
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| posted on 17/12/11 at 06:27 PM |
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washing out with soapy water (washing machine soap) worked for me with calor gas cylinders before i cut it open with a grinder. poured some soap in,
filled with water, left a few days, emptied, and dropped a match in to make sure it was ok 
no explosions... ok, its not petrol, so petrol might behave different, but what i'd do, fill with water, leaving a tiny air space, and position
the tank so that the air is under the bit you're welding, so there's no water pressure on the molten metal.
should be ok
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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MakeEverything
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| posted on 17/12/11 at 06:33 PM |
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quote:
Originally posted by britishtrident
Washing out alone is not enough, petrol has the habit of lingering in seams and reapears when heated this can enough to give rise a mixture
within the explosive range, the lower explosive limit of typical pump petrol is is just over 1% by volume (ie. 1 part petrol vapour to 99 parts
air). Also The auto ignition temperature of petrol can be as low as 250c. Because there is not enough fuel present ignition at levels close to
the explosive limit usually result in a flash fire rather than a fully explosion --- remember the school chemistry demonstration of
hydrogen burning.
The hot work rule is Empty, then Wash, then Steam, then Ventilate.
I disagree.
The properties of petrol say that the mixture needs to be between 1.4 and 7.6% fuel to produce vapour. The liquid on its own is not combustible. If
the tank has been flushed and "contaminated" with soap, then any potential vapour would also be contaminated and combustion risk reduced.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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blakep82
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| posted on 17/12/11 at 06:36 PM |
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^ agree, and soap essentially being a de-greasser, should help either remove the petrols oily film residue, and coat whatever is left behind.
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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r1_pete
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| posted on 17/12/11 at 06:46 PM |
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The exhaust pipe method does work, but, be sure the car's exhaust is up to temperature and the tailpipe is hot, run it into the tank, when the
tank is hot, leave it another 15 - 30 minutes.
A couple of months ago I did braze up some un needed holes in my tank using this method.
I guess having the tank hot teazes out the fuel which has capailaried into the seams.
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escary
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| posted on 17/12/11 at 07:15 PM |
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tank welding
last time i welded a tank i washed it out with a high pressure steam cleaner with dilute traffic film remover soap, then washed with soap free cold
water then blew it out with an air line.
I left the air line in the tank still blowing whilst welding with the filler pointing down and away from me with all of the other holes pluged so that
there would only be one exit blow point ( i may well have been wrong with that assumption ) anyway it worked and held fine until well after i sold the
car
regards
Ewan
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whitstella
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| posted on 17/12/11 at 08:31 PM |
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cheers and thanks
well thanks for all the replies and all very helpful.
i will tell you how i get on, if you hear in the news a bloke made a bomb and killed himself in the high peak its only me (lol).
thanks again for the info.
cheers steve
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Gus
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| posted on 18/12/11 at 08:21 PM |
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When i had to repair my tank, i pressure washed it out first .Then filled it with argon shield gas off the mig welder,kept it running at a low pessure
then welded the tank.
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Neville Jones
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| posted on 20/12/11 at 02:04 PM |
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As above, my local ally welder steams then fills with inert welding gas argon on steady feed.
Car exhaust can be combustible, depending on mixture.
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