[m9e8n7k6e5]

I am somewhat new to welding, but very new to TIG. I have been practicing welding coped tube on pretty much any scrap I can find, but seem to have an issue with stainless when stopping the weld. There is always a little dimple, pit, whatever you want to call it when I stop. I am hoping someone may be able to tell me what in the world I am doing wrong.

This picture is .065 304 stainless 3/32 tungsten, .045 ER308, Millermatic 220, no pulse, set to 80 amps using peddle ~17CFH

My end goal is to weld a bunch of 4130 tube for an airframe.

IMG_0200.jpg (58.72 KiB) Viewed 776 times

[cj737]

It's called "cratering". It is the result of snapping off the arc at the end of your weld. And under structural applications, its a No-No.

To prevent it, begin tapering the heat a dab beforehand, slowly let off the pedal and swirl your torch at the end of your weld. You can even slightly move backwards or forwards as you find a preference.

With stainless, I have the practice of leaving the filler stuck in the puddle. Let it cool, then wiggle the filler until it breaks away. No craters.

[m9e8n7k6e5]

Thanks cj737 I will try that.

[LtBadd]

Welding, in general is all about heat management, but especially with stainless. What CJ described will be even harder to accomplish if the joint is heat soaked. So in a real world weldment where you have more then 1 joint in an area you will need to jump around to other places thus giving the area some time to cool.

If the area is already hot then tapering off to prevent the crater will be more difficult.

[cornmuse]

I am somewhat new to welding, but very new to TIG. I have been practicing welding coped tube on pretty much any scrap I can find, but seem to have an issue with stainless when stopping the weld. There is always a little dimple, pit, whatever you want to call it when I stop. I am hoping someone may be able to tell me what in the world I am doing wrong.

This picture is .065 304 stainless 3/32 tungsten, .045 ER308, Millermatic 220, no pulse, set to 80 amps using peddle ~17CFH

My end goal is to weld a bunch of 4130 tube for an airframe.

Years ago, (30+!) I welded up chrome-moly for a kit plane. I was in EAA, & the local chapter had an actual FAA inspector EAA member. Times may have changed, but at that time the FAA dude said "No tig or mig welding is/was allowed by any amateur (Not certified) welder."

You might want to check with the FAA before any welding, , , , ,

-c-