Low Amps and HF

[brianscott]

Just for kicks I was "Trying" to weld .020 thick stainless using 18-20 amps.
While welding I noticed the HF struggled to start the arc. Is this a normal thing
at 20 amps? I used 1/16 thoriated tungsten.

I gave up, I was more or less burning holes thru the material.

[Buggy Chief]

Was the pre flow on?

[brianscott]

Was the pre flow on?

Yep! Pre-flow was set at 1 second

[Buggy Chief]

That will delay the arc start. Gas starts flowing to shield the tungsten b4 there arc starts. If you want an immediate arc, then turn pre flow on 0.

[Mike J]

Not sure if he was talking about the pre flow - it sounded like the arc just did not like to start.

Brian?

Cheers,

Mike

[Cippee]

On very low amps you have to keep a tight arc and sharpen the tungsten to a sharp point. I have gotten my powertig 250ex to keep an arc going at 6 amps.

[Cippee]

Did you have any luck with the arc? Like I said at low amps you have to sharpen it to the point it could draw blood from you. Also you could try polishing the tungsten with fine fine wheel. Don't use sandpaper though.

[brianscott]

Did you have any luck with the arc? Like I said at low amps you have to sharpen it to the point it could draw blood from you. Also you could try polishing the tungsten with fine fine wheel. Don't use sandpaper though.

That helped! I got it to work. It's just a fine line how close the tungsten
is to the work piece.
I think I need more practice.

[Cippee]

That's good. Yeah at lower amps there is less current to overcome a larger gap so it is more sensitive to a larger arc gap then at 100 amps.

[welderdude]

I don't know if you would see a difference, but I have always had better luck with the ceriated electrodes. I could even get my lift-start tig to fire off at 5 amps, although having it needle sharp makes a much bigger difference.

[Mike J]

Did you get it needle sharp by hand or use a powered sharpener?

[brianscott]

Did you get it needle sharp by hand or use a powered sharpener?

No. I used a power sharpener.
Your saying I should hand grind and then
polish to remove the small grind defects?

[Mike J]

Oh no, I am just curious - new to TIG, and am interested in low-amp work, I may need it for some of the project i am thinking about.

So far, with the welding I have done, and the courses taken, its all been hand ground, using on a diamond stone. I can understand if you want accuracy, it's much better to use a power sharpener. I may get one of those....

Cheers,

Mike

[Cippee]

I like lathinated 2% they are hard to find but work better than anything else. Most places only have 1 1/2% lathinated whitch done work nearly as well.

[Jake98]

I can understand if you want accuracy, it's much better to use a power sharpener. I may get one of those....

Cheers,

Mike

I was dangerously close to dropping three hunderd on one of those, then I tried my 4" diamond wheel grinder (I use on tile) clamped in the vise, electrode in a drill, that cured me. Wheel is about $25.. Those grinders look nice, but they're definitely a rip off.. there has to be 20 times the diamond on a 4" wheel, much straighter longitudinal cut too, from bigger diameter.