[rahtreelimbs]

How do you find the appropriate amperage for tig welding stainless steel? It is so easy to get too hot......the weld turns black.......eventually rust will appear.

[cj737]

I find myself running about 75% of the thickness in amps. For example, .125 material I run about 90-95 amps. For 0.063, I’m running about 43-48 amps. It’s not exact, because filler or fused, joint type, etc all effect the weld parameters.

You definitely need a LOT of gas coverage when welding stainless. You also need to get a puddle and GO! No loitering around and cooking the metal. If your weld is turning black, you’ve got a gas coverage issue. Step up your cup size and turn up the gas. I use a gas lens and a #12 cup almost exclusively when welding stainless.

[Poland308]

Depending on the size of what your welding you also need to be aware of heat saturation. Small or thin parts require lots of small welds and cool time between them. Interpass temps are critical.

[motox]

smallest rod size also
craig

[cj737]

smallest rod size also

There's a scenario where this actually hurts, in that you can't chill the puddle enough so you end up with saturation as Poland indicated. I did some 0.040 sheet for a decorative countertop that demanded filler to prevent burn-back and blow-out. Dropped to a 1/16th tungsten, purged the back, and still had to use 0.045 wire on a flush-fit seam. I'm sure better welders than me could have done it without, but not this old hack.

With stainless, I find its nearly impossible to dictate exact parameters due to the myriad of conditions involved. Thin or thick? Flat or uphill/overhead? Fused or filled welds? Pulse or not. Just too many variables...

[LtBadd]

I find its nearly impossible to dictate exact parameters due to the myriad of conditions involved. Thin or thick? Flat or uphill/overhead? Fused or filled welds? Pulse or not. Just too many variables...

Thick to thin, besides I don't want to be straped to the idea I have to know the amps, you need to just get the machine close and weld with the foot pedal watching the bead to determine what you need.

[tungstendipper]

smallest rod size also

There's a scenario where this actually hurts, in that you can't chill the puddle enough so you end up with saturation as Poland indicated. I did some 0.040 sheet for a decorative countertop that demanded filler to prevent burn-back and blow-out. Dropped to a 1/16th tungsten, purged the back, and still had to use 0.045 wire on a flush-fit seam. I'm sure better welders than me could have done it without, but not this old hack.

With stainless, I find its nearly impossible to dictate exact parameters due to the myriad of conditions involved. Thin or thick? Flat or uphill/overhead? Fused or filled welds? Pulse or not. Just too many variables...

How did you purge the backside? Been wondering this all day.

[cj737]

smallest rod size also

There's a scenario where this actually hurts, in that you can't chill the puddle enough so you end up with saturation as Poland indicated. I did some 0.040 sheet for a decorative countertop that demanded filler to prevent burn-back and blow-out. Dropped to a 1/16th tungsten, purged the back, and still had to use 0.045 wire on a flush-fit seam. I'm sure better welders than me could have done it without, but not this old hack.

With stainless, I find its nearly impossible to dictate exact parameters due to the myriad of conditions involved. Thin or thick? Flat or uphill/overhead? Fused or filled welds? Pulse or not. Just too many variables...

How did you purge the backside? Been wondering this all day.

For the long, flat seams, had a set of hands run a hose against the backside. For corners, I built a purge block jig. I use Western Quick Connects and attain a hose, open the tank, and clamp the jig into position.keeps things square, seams tight, and purge against the open seams.