I bought a Longevity 140 and the spool gun n started practicing and fine tuning and got it pretty dialed in. Within an hour I was laying decent beads. Wasn't perfect but I was super impressed with the machine. Five months later (today) I tried again with it on the same settings--wire speed at about 75 and arc volts somewhere between 7 and 8. The argon pressure is hard to figure and that's my first question. The regulator that comes with the 140 is for argon/CO2 mix, and I'm not sure how the readings for that mix would differ when using straight argon for aluminum. Can anyone help?
This was on 3/16 aluminum cleaned carefully with a wire brush, .035 wire included with the spool gun, new tip in and nozzle. No matter what adjustments I made nothing helped. When I started adjusting the gas , I noticed that after a half hour the pressure in the tank had not changed much (I'm not sure how much but I thought I started at 1200 and it was close to that when I threw in the towel). I was purging the gun to bring gas to the nozzle when I started and stopped and it sounded like it was getting gas. I started wondering if the regulator was stuck and was not getting the right flow of argon through it. I slowly opened and closed all of the the regulator valves to make sure they were working right and the regulator completely failed. I have to buy a new one.
Any idea why they came out so badly when the last time I used the machine they were really solid?
Also, the numbers on the 140 dials--the arc volts are labeled 1--10 and the wire speed is 10 to 100. What exactly do those values represent? The miller welding calculator for 3/16" aluminum gives me the following:
Wire Size & Wire Feed Speed: .035" (0.9 mm) at 425-450 ipm
Shielding Gas & Voltage Range: Argon (AL): 23-24 Volts
Amperage Range: 140-150
How does that translate over to what the Longevity 140 dials of 1--10 and 10--100?
Finally, to just make it easy, I deal with 3/16" aluminum almost exclusively. With .035 wire, can someone recommend settings to start with?
Thanks, Mike G