alloy wagon fuel tank repair

[mark williams]

been asked to repair a couple of alloy fuel tanks, some scum have punctured them and drained the fuel. whats the best way of cleaning all fuel out before welding a patch on over the hole??

 

[langy]

Petrol or diesel ???

 

[mark williams]

Diesel

 

[Gavin_d]

Tricky one this.

 

[doubleboost]

I would just purge it with argon the HSE would go ballistic lol

 

[Gavin_d]

If you put a bigger patch over whole it should be ok. If you pick up any contamination that will be the end of that.

 

[octo0072000]

fill it with water so nothing can vaporise then weld it
proper way would be to steam it out for a few hours

 

[mark williams]

If washed out with hot soapy water a few times would that help. I'm hoping they clean it well before brining it to the workshop.

 

[normspanners]

I would just purge it with argon the HSE would go ballistic lol

I agree, problem is for filling with water his filler is now at the bottom whilst doing the repair, also have you tried to move a truck tank full of anything bar gas? usual size is 500lts!
filling with argon would help the repair as it would be stopping oxygen incursion from inside ?

 

[octo0072000]

I agree, problem is for filling with water his filler is now at the bottom whilst doing the repair, also have you tried to move a truck tank full of anything bar gas? usual size is 500lts!
filling with argon would help the repair as it would be stopping oxygen incursion from inside ?

yes norm my old 1978 111Scania had 2 100 gallon tanks or 1000 litres but in my day diesel was 29 pence a litre in 1986

400litre is more of a normal size nowadays unless on continental stuff saw one Dutchman wagon and drag with single 800litre tank 2 400s welded together

 

[Woody.v8]

When I weld them I just steam them out with plenty of TFR, I Make sure the cap is off when welding to avoid build up of pressure and never had a problem even when putting on big patches or cutting the ends off and shortening .
This is how I do them I'm not saying its the correct way, Be safe!.

 

[Kent]

With care! You issue might actually be clearing the contamination fully and hence getting a sound weld that diesel wont seep from as derv is very good used as a penetrator.
A firm I used to work for were removing a diesel tank and ended up with 4 fire engines on site, so do consider if it is a worthwhile job to take on.
If it were me (and I haven't done this in years). I should get the tank cleaned fully then cut a bigger hole plate it then weld it off the truck only.
How much will it cost for a new tank btw? as it should be an insurance job surely?

 

[mark williams]

He not asked for my price yet and when he gets it he might decide on a new tank instead ha ha

 

[Kent]

Might be worth finding how much the part costs new or s/h yourself first? I don't have an AC tig here but I wouldn't personally take this on if I had unless the client had no other option left

 

[lotus 30]

Looked at your location i am in south wales chepstow newport area hope i don't hear the bang try pricing a new tank first

 

[hotrodder]

While diesel tanks are usually considered less risky than petrol (flashpoint etc) if it's someone elses tank how do you know there hasn't been a recent misfueling incident or the like? http://www.ccohs.ca/otherhsinfo/alerts/alert107.txt

There's two sides of the fire triangle to play with but the only way to be 100% sure that it's safe without filling with water or purging it lots is with a meter to check the LEL and/or the O2... water has it's drawbacks even when the tank is smallish and with large volumes (cost aside) it's relatively easy to waste a bunch of argon and not lower the O2 content that much although that said you've got to do things very wrong to not get the O2 down to safe levels

 

[mark williams]

Starting to think this job is not worth the hassle.

 

[langy]

Steam it out well

Starting to think this job is not worth the hassle.

Correct, A while ago I welded on a petrol tank that hadn't had fuel in it for 30 years, still got a little flash from it when the arc struck

 

[mark williams]

What if you light the tank with match just before welding would this not clear the build up of vapour?

 

[daleyd]

If the mix of vapour and oxygen is just right it'll certainly clear it ok, along with anything else in your workshop !!