How to weld a fuel tank?????

subarursliberty · Post by **subarursliberty** » Sun Mar 11, 2007 9:48 pm

So how do you go about it so you don't blow yourself to kingdom come.

I'm planing on buliding a surge tank for it so I don't have it in the boot.

Also you recon cutting and welding a tank is legal?

Suba · Post by **Suba** » Sun Mar 11, 2007 9:55 pm

You would be better off putting the surge tank in the engine bay.

Mike.

subarursliberty · Post by **subarursliberty** » Sun Mar 11, 2007 10:17 pm

Though about that but would like the engine bay clean and tidy. Battery is in the boot now.

AndrewT · Post by **AndrewT** » Sun Mar 11, 2007 10:17 pm

I don't think its illegal to modify a fuel tank. Pretty sure people usually fill them with water a few times before getting a spark close.
Nothing wrong with running an external surge tank tho. As Mike says, the engine bay is a good place. My Mazda has one mounted down near the fuel pump right near the petrol tank. Not sure if theres room in a Suby for this though.

D3V1L · Post by **D3V1L** » Sun Mar 11, 2007 10:19 pm

wash the tank out with water and metho twice,....then just clean ater twice...this will get all the fuel and vapour out and wont go bang..but make sure its bone dry before spark goes near...ive built and modified 2 fuel tanks before and this is the method i used and im stil here.. dave

subarursliberty · Post by **subarursliberty** » Sun Mar 11, 2007 10:34 pm

Thanks guys. Engine bay is out of the question. If i'm going to the trouble of moving the battery. Boot maybe.

In the end I like things tidy and hidding. Heaps of room back there in the tank. i will prob use 90 x90 SHS at about 150mm - 190mm high. The tank itself is 150mm thick.

julian · Post by **julian** » Mon Mar 12, 2007 9:02 am

As dave said as per washing and drying, i left mine in the adelaide sun for 2 days before i even looked at the welder.
Just a note of caution, even if your battery is a sealed type, i recommend a battery box. I reckon (in SA at least) there is some CRAZY law about fuel lines and open battery terminals anywhere in the cabin behind the firewall.
Julian

steve_rising_sun · Post by **steve_rising_sun** » Mon Mar 12, 2007 9:56 am

I have seen tanks go 'Bang' that have been water flushed for 24hrs and dried out etc. Try filling with mig gas or exhaust gas, after flushing for 24hrs minimum. Use maximum caution, people using the same old safe method can one day end up being peeled of the roof.
Last death in Adelaide was about 5 years ago.
Steve

Oversteer · Post by **Oversteer** » Mon Mar 12, 2007 1:39 pm

You must fill tank for > 48hrs(72 hours better) with water(little detergent in it helps...then fill with inert gas(shielding gas, argon, co2 etc). Then you still need to have the tank vented well so if it goes woof, there is somewhere for gas/burn to escape, c02&argon is heavier so vent at top point.

Surge tank under hood, me not think such good idear unless its a drag car than only runs for a minute or 2....heat soak and vapour lock issues under hood will rear thier ugly head....not to mention correctly venting such a surge tank back to existing vapour system.

I like your thinking tho, built in surge system in the tank would be good, followed by external tank and pump near tank level or below in rear of car being next best thing....

OS

subarursliberty · Post by **subarursliberty** » Mon Mar 12, 2007 5:09 pm

Battery is in a box. Has to be sealed in NSW.

Might flush it out for a couple of days. Might even run the washing maschine water through it for a month. I might even throw a cracker in it down the local park one night after it has been flushed and run like hell.