fuel tank repairs

[Not Happy Jan]

I haven't had any fuel in the tank for over a year now and am wondering if its safe to weld up some holes in it. If I blow a constant stream of air in it would that be OK.
I cant smell any fumes at all.
I can put water in the tank but not enough to anywhere near fill it.....too may holes. The holes where made by me while using a puller to straighten it out. I do have another tank ... but I would still like to repair it.!
Nick

[John253a]

Wash it outas best you can with water 2 or 3 times, then blow it to remove water before welding,

After it's patched are you going to lead all the seams?
That's what I did on another tank I did,

There is also a 2 part epoxy mix for sealing the metal and treating the inside of tank,
Can't remember what it's called but it good stuff,

[87 velo]

Another way to purge the tank is to run exhaust gas through it.  The exhaust fumes remove the fuel vapour, make sure the exhaust gas you run through it is from a clean running vehicle, no miss fire, hot engine otherwise you could put more HC's (hydro carbons, unburnt fuel) in. 

Late model car with a catalytic converter probably best,  I have repaired a few motorcycle tanks with this method successfully.

KBS does a tank liner, there are some others on the market as well.

There is a method of cleaning the inside of the tank using electrolysis, you need a battery charger washing soda and a headlight globe, if you're interested I can dig up the details.

[mcl1959]

All petrol should be well and truly evaporated after a year, but a rinse with water and air dry can't hurt.  Remove the sender unit if you are welding near it so you don't burn the cork float. Any tank that is not rusted on the top is worth repairing and is quite valuable.

Ken

[FC427]

We use to run the exhaust from a car in to an empty the fuel tank for 20 minutes then weld it with out ever a problem in the old days but after working at the Shell Refinery and learning a little about how hard it is to gas free vessels  I would take it around to REDI STRIP and have it cleaned in there tank, they soak it for 3 to 4 days to get it gas free .......FC427......

[FCRB26]

Its not worth the risk fiddling with trying to purge fuel tanks
  i have them dipped up the road in the acid bath just too easy for it to go bang and too hard to get rid of the gasses.

I have done a diesel tank but i used a caustic type of cleaner to clean it then purged with argon.

[Not Happy Jan]

OK. thanks for the replies.  I think for the OH & S point of view Ill get it dipped and treated then weld it up.
I tried to get the tank out a few weeks ago but the rubber seal around the neck was tight as all get out and I thought that Id snap something. Do I just cut that off to remove the tank??? and the neck should slide out
Nick

[FCRB26]

yep just cut the old rubber or get a flat piece of steel say 25x6 and push the rubber out from the inside or whack it with a hammer and break it out.

[mcl1959]

You will find that the wagon has 2 rubber seals as the tank goes through 2 panels - this is why they get a bit tight. Cut the outer one away with a sharp knife and then it should come out easily.

Ken

[fe350chev]

Make sure you have undone the fuel line first