fill it with exhaust fumes
WTF? Your method consists entirely of lack or preparation!!
PS. Did mythbusters used tanks with fuel in them so the mixtures were too rich for explosion, not tanks drained of fuel that have a significantly higher chance of containing an explosive mixture.
if your weldinf alot its a bad idea to fill it with water because when u weld it will heat and boil the water which creates steam and can defect the weld.
ps. did they shoot it with live rounds ?
Originally Posted by biggo
I work in the oil and gas industry and deal with welding and repairs on all sort of vessels containing hydrocarbons every day. What SamQ said is right on the money. Purge it as he has said and it will be perfectly safe.
ToddW
i got a hose connected to car exhaust and ran the car while i was welding, didnt die! i saw a moto tank go up at work the other day luckily only just a little flame and no explosion but a little more fuel and it would have gone boom!!!
AE86 THE BEST
Working in that industrie you'd be aware they they do modifications to LIVE pipes... Ones that are in survice containg fluid.. And yes I'm aware that flamable liquids are not as conbustable as their fumes.
I added the lack of preparation bit in the chance that 1 in a million does occur...
You are correct in what you are saying WRT the welding of live pipework. That is only if it meets numerous requirements. The most important being that the process is still flowing which infact helps with the cooling but it is worth mentioning that there cannot be an explosive atmosphere due to being no oxygen present. With the comment about draining the tank and letting it sit a for a while and then weld away I strongly disagree. DO NOT EVER do this. Any vessel that has had hydrocarbon in it needs to be purged prior to welding. It can be exhaust fumes or even better water or nitrogen if you have access to it but do not heat or weld a tank or vessel that hasn't been purged. It can and has killed people. I remember when I first started in the industry there were a couple of welders killed and one badly burnt welding on a crude oil storage tank. They had a permit to work on the tank to remove the access ladder and weld it in the workshop which they did. They did a trial fit and it needed further modification. Rather than remove it and take it back to the workshop they went to weld it in situe. On the first strike of the ark ithe tank blew into pieces with them also. The tank was empty and had been for months but still had an expolosive vapour in it. Crude is nowhere as volitile as fuel so the moral of my story is always purge as described above.
ToddW
connect a vacumme cleaner to the filler neck while welding the cut out onto yur tank, heard its the way a few people do it to get rid of excess gasses. prob not that good for the vacume cleaner tho
20V silvertop, HKS 2510, Microtech LT10s with dash display, A Spec coilovers, AJPS RCAs + traction brackets, T3 adj trailing arms, TRD 2 way, braided brake lines,Kelway half cage, Cusco cambertops and braces. 174rwkw @ 15psi....SOLD
CA18det Gayzelle cooner
why the hell do you need to weld on a petrol tank anyway? whats the point like what can be done with it?
Cutting the top to accomodate a different housing for EFI upgrade + custom internal baffle / surge protection to avoid killing pump by running it dry...
1982 panelvan never came as a fuel injected model so I need to customise the original tank. I already had under car fuel surge tank installed ready for my engine conversion but it's all a bit tight set-up in there with the diff being so close to the fuel tank. So I'm going for a more factory-type arrangement.
Thanks to those who have posted, it's been pretty helpful. I will most likely wash it out with warm soapy water a few times and do the monoxide trick for 15 mins to make sure it's all safe.
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