alloy wagon fuel tank repair

[premmington]

I purge with pure argon or nitrogen! Filling up with water works, but has it drawbacks!

I really have had problems welding up diesel tanks in the past! Petrol tanks seems to present less of a problem!

Diesel really gets into rusty steel! (I know yours is alloy).

 

[doubleboost]

I remember many years ago fitting a "bag tank" (flexible plastic tank filled with pan scrubber type material) to the inside of a racing car monocoque
We used to cover them in talk then "suck" them flat with a vacume cleaner.
This tank had been used we could smell the petrol fumes
It took weeks for the ringing in my ears to subside , we never found all the bits of the vacume cleaner
Happy Days LOL

 

[Norm]

Lol bet you said b@st@d

 

[langy]

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

 

[Kent]

Your right its not worth the hassle!

However,
Diesel ignites via the fuel itself not the vapour left in the tank does it not? I have done this type of job before but its an age ago and I just cannot remember the facts fully enough but its horrid stuff for contamination this I do know

 

[mark williams]

Iv done a steel tank before but never ally. If the price is right ill have a look. Will take a few hours flushing and cleaning the tank. So its not gonna be a cheap job.

 

[normspanners]

The issue is diesel is not as bad as petrol for igniting, and it still can, but winter time sees additives put in the fuel to stop waxing, that is usually kero which is closer to petrol and can ignite with a spark but also people put in petrol in the fuel tank to help stop waxing, this is the big problem the petrol or kero vapour is still in the tank seams etc.
I repaired one off my recovery truck (special shape large tank) and we washed it several times with tfr etc, I left it to stand with no cap/ bungs/ pipes etc then 'flashed it' at the open neck , with a lit rag on a long fishing pole four times it flashed ( WOOFED), (it just shot a large blue flame out of all the orifices) before it lost the vapour then I redid the flashing many more times before I deemed it fit to weld but I still wore two leather coats on backwards and a rubber mat between them and my front !!
I had no issues but I cant say I was at ease.

 

[mark williams]

What would you guys think price wise per tank. Iv not heard back off the bloke yet may be he is pricing new tanks. Is a patch 1"overlapping the hole all way around adequate of say a gauge thicker material than that of the tank?