O.K., I'm going to try tigging SS.

Stainless steel huh ..... ? passivating ......? are you plannig to eat out of that pan, or did I read it right it is a for a band saw? :-)

beside the joking :- )

I got a 4x6 saw and made it in to a wet saw. but I simply used galvanized sheet metal left over from an A/C installation. I did not even bother welding/joining the corner seams, because, the coolant (cutting fluid) is at the center ,so does the coolant dispensing tube, I simply hit the center of the pan with a rubber hammer a couple times making it it lower than the rest of the pan, then I drove a big chisel through it giving it a place to drain . The cutting fluid never even goes toward the edges of the pan. The saw cover up the drain hole.

you guys got too much time >I got a pan bent up at the sheet metal shop, and will weld the corner

Peter,

I think you may be over doing it for a simple catch pan. IMHO, the back purging and passivating are a bit over the top. The 1/16" filler rod is OK, though ideally you don't want the filler bigger than the base metal, and as a new convert to Lanthanated tungsten myself, I would completely concur with that choice. (Like that means anything:)

As for the fit up, I personally don't use any jigging, unless the piece is really heavy and not broken up close enough. Then it's time to bring out the furniture clamps and BIG dead blow. I built an 18 ga. SS pan today,

6'x3'x6" deep, built in 2 3'x3' halves and butt welded together, with a 1" coupling welded on one side. This pan is going to be a "just in case" catch pan in a local chicken processing plant, and all I had to do for clean-up was wire brush the brown off of the welds and grind any "sugar" off the back side of the welds.

Now don't get me wrong, back purging and passivating have their place, but for a catch pan it is overkill.

Of course, if you are just wanting to practice, knock yourself out Peter!

Regards, Jim C Roberts

Sounds like a nice pan, I would butt the corner together with no gap. Make your weld on outside in a flat position. You can use foil and tape to cover the inside corners & purge. Good Luck.

Hi

Recently gone from zero to something doing s'less TIG.

I would back-purge, because

- it's good expereince

- you'll know what a weld SHOULD look like

- you have to live with the thing looking at you every day

- the back of the weld flows better

Let me qualifiy the last one.

It welding without backpurge, in air, and you are working slowly, you will get huge encrustations of oxide grunge on the back surface (the oxidised Chromium and Nickel) which prevent the back surface flowing. Wehn more used to stainless and you get a move on and use a larger weld-pool, you do get flowing and the bead and backbead shape are OK - but you have got oxidation.

Even an expereinced TIG weldor in othe rmaterials will find S'less different as thermal expansivity twice that of mild steel, while conductivity is half that of mild steel. Consequence - big distortion, compared to mild steel. Other conseq. is need less heat. So exp'd weldor may be running slow on s'less.

Any reasonable backpurge will be a huge step in the right direction. Food-grade industrial - backpurge is good enough that the strongest colour patina from oxidation is no worse than light straw. Any better than that and the back-bead and HAZ is silver (no oxide). Light straw comes of a pretty good backpurge. Maybe relax a bit on this seeing as it's a pan under a saw!

Had advice on backpurge, when making craft objects, which I have mentioned elsewhere. "You've backpurged this haven't you? This is better than 80% of the commercial welding I see. That's your problem. Out there, there's a lot of people, they don't give a s*&t. They don't backpurge. They've got a foreman (doing something unspeakable to you) unless you just get it out there".

Take your pick...

Richard Smith

Seeing is understanding.

See the pic

which is the last pic on page

which is what you want to go to as it has the pix and comment combined

It shows a weld with and without backpurge. The picture tells the story.

Best wishes

Richard Smith

Very cool. Thanks. As a hobbyist, I intended to rig the backpurge not because I needed it on a pan for a bandsaw, but because I wanted to learn how to do it, and what the effects were. Learning is a large part of what I enjoy about this hobby.

Don't worry, I'm not going to emulate the first reply, something about boogering something together with an axe or big hammer or something. Yeah, I could make a drip pan out of some twigs and a garbage sack, but I wouldn't find it informative or fun.

Thanks again.

Pete Keillor

yes it would be fun to see ..... and can you make one out of twigs andd a garbage sack? the issue is that you have a TIG machine and don't know what the hack to use it for.

Dear Pete,

I , ( first reply), was not trying to flame you or your post , and that is why I put the word " kidding" and the sign :-)

I am glad you are enjoying your hobby, and the learning curve it throws you. I was simply saying it is a waste of good material for a wet saw drip pan, regardles how well it is done.

there is simply not a good reason too use stainless.... even tho you may think it will not rust. don't even want to get started on the passivating.....

cutting fluid + metal shavings (free iron) will go to work on the surface of the stainless in a hurry.

back purging and passivating SS is a good thing. I would have used the stainless for something cool like a giant beer or lemonade mug and be proud of the stainless- hobby work you have accomplised.

Ok..... beside the bitching... and sorry if I have offended you. it just make me sad to see all the waste , that we Americans do. but that is just me, and my oppinion, may be I am just having a bad day........