Outer Limits 4x4 Board

Does anyone know a good reason why I cant make a custom fuel tank (to accomodate wheelbase strech) from 3mm aluminium and thesehttp://www.durafix.com.au/index.php?content=home.htm

if you can find a small sheetmetal shop near you get a price on having it tig welded depending on size price will differ but you would be unlucky to go over 100. anything you do with a propane torch you will be basicly glueing it together and when 4x4ing i prefer a bit of penetration in my welds

3mm ally is too thin for a belly tank, it will pearce ease. I was recomended 5mm ally, but went with 3mm steel.

Most aftermarket tanks are 2mm steel, but if you take it off road I would go for a thicker bottum skin.

Why? Those things look like they are for aluminium "repairs" as it says in the article, and they are also 'brazing', not welding. I'd imagine you'd have a prick of a time ensuring theres no leaks... If you wanna practice welding/brazing etc i'd probably practice on something OTHER than a fuel tank.

And if your gonna take it to a shop to get welded, you may as well get them to cut/notch/fold it up, & then pressure test it... And while your there get it done out of stainless or mild steel, unless you plan on running some sort of bash plate for protection...

If you make a diesel tank out of mild steel do you need to paint the inside to stop it from rusting or will the fuel protect it enough?

never had a rust problem with deisel tanks, petrol either unless the petrol tanks sit empty for long periods.

I have had painted tanks have paint peel off n clog filters n lines though.

Nelso wrote:If you make a diesel tank out of mild steel do you need to paint the inside to stop it from rusting or will the fuel protect it enough?

just keep it full all the time

can make pretty much any size and shape tank you like in stainless
CHEAP!!!

stainless is not the best for 4x4 water or fuel tanks, it is prone to cracking.

I have done a few, n also have done quite abit of stainless work n wouldnt use or recomend stainless for most things on a 4x4.

nastytroll wrote:stainless is not the best for 4x4 water or fuel tanks, it is prone to cracking.

I have done a few, n also have done quite abit of stainless work n wouldnt use or recomend stainless for most things on a 4x4.

x2

that may be due to your technique no offence

i think they normally use an aluminised steel or something like that, as stainless cracks with the vibration and ally is too soft.

dont shoot me im only going on what i have heard int he past..!!!

I cant realy see how my bad tig skills will cause 316l stainless to work harden n crack.

The welds did not crack but the sheet did, this was 2mm thick.

There are places for stainless, this is not one of them.

I have never said I was a good tig welder, I have 6 years experience in food machinery, pipe work, and I used to do the proto type work for a stainless steel battery tray company.

How ever there is always some thing new to learn, so feel free to show us how to do it right.

was the tank purged
were all welds passavated
were you using 316l wire
was the tank you made bolted down securely
i make a lot of transport tanks for wine that go on back of trucks on the road all the time driving around hunter valley some of these roads around the wineries resemble 4x4 tracks never had a tank crack i also make ss gas scrubbers wich go underground on all heavy earth moving equipment
again have not had a problem

tanks were purged, all tig welded with correct wire and baffeled.

Problem is the weight suspened under the vehicle, and the expansion and contraction of the fuel work hardening the stainless.

nastytroll wrote:tanks were purged, all tig welded with correct wire and baffeled.

Problem is the weight suspened under the vehicle, and the expansion and contraction of the fuel work hardening the stainless.

How were the tanks mounted to the vehicle?

supended from ends, the cracks were in the sheet though, not through the mounts or joins

Were both ends mounted solid, or was one end mounted through rubber bushes. If both ends were mounted solid then as the chassis twists the tank tries to resist it. With the solid mounting it would allow for some movement.

Correct me if i'm wrong but doesn't 316 stainless strain harden really quickly/easily???