Evening all,

Petrol tank on my daily driver sprung a little leak a while back after I reversed over a tree stump in the work's car park and on sunday I tried to fix it but it just got worse.

Question is: The tank is now off and the leak would be an easy fix with the welder - about 4 spots and I've saved myself £60.

BUT....Im a bit anxious just to go for it since I might blow myself up - Buuuuutttt SURELY if I leave it for 24 hours in the back garden to dry out it should be sweet??? Or swill it out with something like water??

So your thoughts gentlemen - and no "Bonfire night gags" either - I've gotta get it sorted cos Guinness is coming to borrow it tommorrow night!!!

(If you're reading this Mike - dont worry - the cars a minter!)

Geoff

Sorry, but a VERY big no-no unless you can fill the tank with water and still weld it. Even then it should be left for some time as in a week or so first. Much better to clean up the damaged bit and mend it with something like JB weld epoxy. I have done this a few times and usually with success.

Fill it with water, let it run through for a while if you can to wash to petrol/fumes out and leave it full of water when you weld it, should be fine, it's the fumes that are the problem..

Hmm,

Just been reading this:

http://www.hse.gov.uk/pubns/indg314.pdf

It seems to suggest, as you both have, that filling it with water could be the job - I didnt like the bit about solid residues though.

I knew the HSE would wee on my fire.......(sorry I couldnt resist that!)

Geoff

Or steam clean the inside.

David

put a pipe on an exhaust and run the gas through for a while,a rinse out with some detergent helps,stand well back when you spark up,ive done loads and i,m still here

Bubbles. Lots of them.


Some washing up liquid and water and shake away. Me father's been welding tanks for forty years without incident.

Cool so the carbon monoxide kinda purges the tank?

Sweet plan!

If only I could start the car to get the fumes in! It'll have to be motorbike fumes!

Geoff

What about liquid metal? I've not used it before, but it may be a possibility.

Fill it with water and weld it. Under no circumstances try to weld it without water.
It's the fumes/air that explodes.
I remember as an apprentice being told about a guy that was killed when an air tank exploded as he tried to blow a dent out with compressed air. The pressure wave went up his nose and burst his lungs
He was told to fill it with water first as you cant compress a liquid but he thought it was quicker his way.
The principles of what you want to do are the same though. So if it all goes tits up would you rather be pissed on or blown away.

He he. Id go the jb weld or petropatch route.

You could just fibreglass a patch on, nice and easy. If you weld it empy, film it and post the results. Could be good for a laugh.

No I met a guy name stumpy before, he got his name from welding a gas tank, they do make a product specifically made to seal gas tanks.

Don't rush the job on my account. I got your message but too busy to think at the moment. Have just decided to drive up, lot less bother than a trailer.

Be safe.


P.S if you do blow youself up can i have your turbo!?

Mike

Petropatch , safer and cheap!

Why not buy a new one....

I have brazed a pipe on the top of tank before. I filled it with water, but could not get enough heat in the metal so I drained off a little and tried again. It worked fine until the vapour built up an ignited. Luckly the explosion was contained within the tank, which took a new shape of slightly ovalled and shot a jet of water about 100foot into the air. (Made a nice noise though)

If the hole is not too large I would recomend POR-15 Tank restorer which basically creates a new tank inside the old one. Costs about 15quid and is available from frosts. www.frost.co.uk.

didn't go into details but I have had similar experience to big stu when migging a tank that had been empty for over 3 months.

The vapour is not the issue, it's the vapour formed when petrol residues are driven out from the surface of the steel, even though it appears clean.

not saying it;s not possible cos I've done it but it's risky even when you think you've covered everything!

Unless you can clean it by detergent soaki over night THEN steam it out for several hours don't even think about welding it.


PetroPatch (shellac based) covered over by a layer of glasfibre will work well.

I'm with triton buy a new one,its a kinda guarantee that you will live longer

I spent an afternoon trying to weld a BIG landrover fuel tank. I had it full of water but each time you weld the thing brews up a chucks water everywhere. To get a weld without pinholes is very difficult when the steel is wet to start with.
Either do the scrap yard route or buy new.

My Dads fixed a tank with fiberglass, been good for 5 years.. He only did this as he is tight, and the replacment was expensive (classic car). Don't weld it, petrol explosions are not somthing to play with for 60 notes...

the effect of welding a tank without water in it can only be explained by the same principles used in the guy fawkes experiment with hammond the hamster last night

Welded it empty in the end and Im still alive!!

I washed the inside out with detergent and then dried it for about 2 hours with a hair drier wedged into the fuel inlet hole and waited until I couldnt detect any petrol odour coming out....!

I must admit it was the most exciting bit of welding Ive done for a while but its all fixed and petrol tight - phew!

I "belt and braced" it with some epoxy tank repair stuff from Halfords on the outside.

Cheers for your concern gentlemen but it would seem, this time at least, I got away with it!

Six lines will be placed on the lottery this coming saturday....

Geoff

[Edited on 3/11/05 by jambojeef]