Works great at 130-150 amp but it crackles (sputter) at around 50-75 amp

[vicrc]

I have been practicing welding beads on 1/8" aluminum sheets 3/32 2% lath tungsten 150 amp and using the pedal at 15CFH argon, and it seems to be going great, 110HZ and 30% balance. However for the life of me I just cant seem to get a stable arc with amp settings in the range of 50-75 when practice beading 1/16" aluminum sheets. It would sputter intermittently at this amp range, I have played with frequency and balance and nothing seems to stop the intermittent sputter either with 1/16 or 3/32 tungsten. The sputter seems like it is cutting in and out very quickly. Going back again on the 1/8" aluminum at 150amp and it works fine. All my test parts were prepped the same way. I have had no trouble with DC on steel at low amp setting of 30-60 amps and the arc is smooth. I even ground clamped the part and has no effect.

I appreciate any advice you can offer? Thanks

[Rambozo]

The only thing that comes to mind is to back down the argon a little. What size cup are you using? If you are using an Everlast flowmeter, remember that it is calibrated in liters per minute not cubic feet per hour. A little AC arc instability at low amps when you first start is common, but it goes away once both the material and tungsten are hot. What is your arc length?

[everlastsupport]

My first thought would be arc length and is there any air flow around you (fans, vents). And try less gas as well. #7 cup and 8-10Lpm with our flow meter to start out.

[vicrc]

Thanks for the response guys!

I am actually using a Prostar air regulator that I got from Praxair that show CFH instead of the stock valve. Don't have a leak as I can leave the valve open all night and the pressure is the same on both tank flow meter. I am using a gas a lens and went back and forth between the stock lens without much luck while using #7 cup. I set the flow to 15cfh and did not play much with the flow rate. I check the flow rate by pressing the pedal and see the flow meter and its at 15cfh.

As far as arc distance, I don't think i can get any closer. I understand the crackle with the start but when it starts going it should be smooth like on higher amps. Low amp it crackles and really throws me off while adding filler and it does this around every 1/4" to 1/2" of welding.

[performance]

On AC, you will find that the issue is probably you are getting the tungsten too hot at that amperage for its size. I know what the charts say, but often they are wrong, especially related to inverter welders. If you are using 3/32 at 150 amps, you probably should step it up to 1/8". Which unit is this?

[CGCINC]

What welder are you using? I had a problem getting an arc started with my 250ex down low in the amps until I turned the start amps knob to "0"....????

[vicrc]

On AC, you will find that the issue is probably you are getting the tungsten too hot at that amperage for its size. I know what the charts say, but often they are wrong, especially related to inverter welders. If you are using 3/32 at 150 amps, you probably should step it up to 1/8". Which unit is this?

My problem is not with this setting, its when doing 50-70 amps AC, I get the sputter. have tried both 1/16 and 1/8 tungsten