Welding Stainless Steel Sheet

[Brett Butler]

Sorry I know there are loads of posts it is so hard to try and find one that suits my needs

I need to start welding mostly in Stainless Steel, anywhere from 16 gauge to 22 in general

For the most part no polishing is required to start off with.

I need to make up a load of stainless steel Tundishes, 22 guage, (Boxes) approx. 4 x 3" square, 8"deep, they have to hold water thus not leak.

Best type of Welder to do this, for Price etc.
Some form of sheet cutter
A way to cut the sheet corners for the folding.
A sheet folder to fold the boxes into Shape.

I also need to punch out a hole 1 1/16" in the bottom of the tundish, I have a 1/16" cutter but be nice to find a quicker way.

This will lead to many other jobs of a varying degree all in stainless steel.

I might add have loads of 2nd hand stainless steel sheet to play with.

Thanks

 

[hotrodder]

TIG is typically the process of choice for thin stainless. If you're new to welding then thin stainless with TIG is akin to jumping in the deep end with your wrists tied together... more detail on the welding process here http://www.mig-welding.co.uk/tig-technique.htm Note the bit about controling arc length within around 1mm, once things get to 22swg you really need to be able to do better than that as stainless will distort like you wouldn't believe given the chance- precise control of arc length and heat input makes a difference here.

Regarding sheetmetal tools like folders, shears etc... while capacities in different materials are sometimes listed they often aren't, if a material isn't specified then the specs will be for mild steel. Stainless is tougher and a rough rule of thumb is to de-rate by 4 metal swg thicknesses i.e. something that's rated to cut/fold/punch 16swg mild steel will typically be rated at 20swg for stainless. Check out 'Q-max cutters' for sheet metal punches, you'll need to give us a budget for the other stuff... for example if you've not got any money/are tight then a jigsaw will be the cheapest way to corner notch 16swg and 22swg is within the relm of tin snips. Thin stainless is eleventy billion times easier if the fit up is perfect, a corner notching punch would therefore make sense but they cost more...

 

[Shox Dr]

As usual HR is spot on.

I would like to add more weight to, welding Stainless Steel is no fun if you haven't welded before. Welding SS less than 1.0mm is a skill that many a good welder finds hard to master. I've setup tests (lap, Corner, Butt etc) for coded welders, and they have failed.


Fitup is King, I would look into getting the parts notched and folded, insist on a sample: the fitup (gap) should be perfect, if they know what they are doing.
That way the seam can be welded autogenously (without adding filler) this cuts down on post weld cleaning, and greatly speeds up welding time, and thus cuts down on warpage.


Good luck

 

[TechnicAl]

When you say you have loads to make...would the job run to an investment in a fancy MIG set. These days there are MIG sets that can put down TIG quality welds whilst controlling the heat input and the subsequent distortion inherant with stainless.
I wont mention names but all the big guys have one..........but they arent cheap

 

[Shox Dr]

They sure aren't. DC 160amp* TIG from the other end, would walk it as well with a bit of practice



* I say 160amp as that seems to be the starting amperage for HF sets

 

[Brett Butler]

Thanks for replies.

I have done arc welding in the past, a long long time ago.
I have a load of q Max cutters, but prefer Greenlee, as the bolts are bigger. I have a jig saw, and a Makita nibler. so a quite a bit of the basic tools belt linisher, grinder etc.

I have quite a few things that I could make, that I use for work, like 3" stainless steel traps etc. that in the past I have had all made out, but the demand is more now to the point I rather look into making it myself. It is just all Stainless

If the arc has to be so close how do in weld into an L shape corner.

I might add the welds not going to be seen, so it will not be ground down and polished. it has to be single phase 13 A

 

[Paul.]

As said, jumping into 22swg stainless with no tig experience is going to be a very steep learning curve, welding inside corners on that thickness is extremely difficult to do without burning through and sugaring the back of the weld, a pulsed set will help but in my opinion you still have to learn to tig weld traditionally first,
On inside corners the gas is contained by the joint, therefore you can afford a smaller ceramic and a longer tungsten stickout to reach into the corner, a flexible neck torch is useful and practicing torch / wrist manipulation is essential to be able to get round corners without stopping to minimise the chance of leaks,
This is a 3mm angle and really the kind of thickness you should be starting out on to master the techniques

 

[hotrodder]

One way is to weld out of the corner. Other ways of dealing with tricky access involve changing the way wire is added... can bend the wire when an obstacle prevents you from feeding it, it can be added from the side instead the leading edge but we're getting ahead of ourselves. Difficult to describe, basic 'angles of attack' are covered here http://www.millerwelds.com/resources/improving-your-skills/tig/, if you read the rest of the TIG tutorials and watched the vids you'll have seen some of the changes in angles and tungsten stick out etc.