Stainless Tank

[SBK]

I have a 1200x600x600 tank to make for someone out of 2mm 304.

Whats the best way to weld the joints as I dont have access to a bender.

Should I autogenous weld the inner then clean up and go over the outside ??
The tank is only for water non drinking.
Any help appreciated

 

[BrokenBiker]

i made a stainless tool box on my welding course and we pretty much just clamped it up and then autogenous welds all round on outside, didn't touch the inside at all.

not sure if you need the inside to look clean ad my method left a bit of oxidation on the inside of the box

 

[SBK]

Yeah Thats what i want to avoid,don't fancy back purging a box that big !

 

[BrokenBiker]

your way sounds about the best then but others may have more ideas

 

[Paul.]

For a non food application you could just weld it from the outside, make a good fitting open corner joint and put a close fitting backing bar inside, use a filler rod and aim for penetration, the backing bar will contain the gas in the back of the joint similar to but not as effective as purging, and also aim to build up the corner to give it some reinforcement, autogenous welds on something like this is asking for weld failure in the future, a lot of the repair work that I do is re-welding autogenous welds that have failed,
This is the method I used on the tanks in this thread, http://www.mig-welding.co.uk/forum/threads/wash-tanks.45453/
and this one http://www.mig-welding.co.uk/forum/threads/another-trolley.33156/
These are both food industry applications, but for cleaning machine components not direct food contact,

 

[SBK]

Paul should the backing bar be aluminium to help with heat ?

 

[Paul.]

I use a piece of stainless angle, put small chamfer on the corner with a linisher, you can tack bits to it to get your clamps on to hold it, aluminium would be fine, copper even better but not so easy to find, flattened copper pipe can be useful on some jobs, avoid steel it will contaminate the job, tack it up well, about every 70mm or so will do, autogenous tacks are ideal then you can weld straight through them, spread the welds around (skip weld) to keep the heat down, air quenching with a blowgun works well too.

 

[SBK]

Thanks Paul will post the results