A few questions about the ARC Force knob on my 250EX??

[CGCINC]

First question is HOW does this work? I don't understand how you turn a knob and it can make the arc wider, then turn it the other way and it focuses the arc? Amazing.


Second question: When welding Aluminum, is there a setting this should be at or just whatever works for me?

[jerky]

Think of arc force as a penatration knob, the higher u turn your knob, the better it will "dig" into your base metal.

[parkour]

It controls arc current as a function of voltage, or how much the machine will increase the current for any drop in arc voltage. The arc voltage is determined primarily by the gap between the electrode and the work, and what elements makeup the plasma (the arc). With arc force at zero, the machine should produce the same current regardless of arc voltage (gap); of course, within the machine's electrical limits. With arc force greater than zero, the machine will decrease the current as the arc voltage (gap) increases; the rate of increase being dependent on the knob setting, and again the machine's electrical limits.

Here is a lengthy explanation from miller.
http://www.millerwelds.com/resources...rticle108.html
Mark gives an answer in another thread
http://www.everlastgenerators.com/fo...t-is-arc-Force
Ben Krasnow has a comment also.
http://benkrasnow.blogspot.com/2009/...r-welding.html

As a general rule, the settings should be at whatever position you find it easiest to produce an optimum weld.

[CGCINC]

It controls arc current as a function of voltage, or how much the machine will increase the current for any drop in arc voltage. The arc voltage is determined primarily by the gap between the electrode and the work, and what elements makeup the plasma (the arc). With arc force at zero, the machine should produce the same current regardless of arc voltage (gap); of course, within the machine's electrical limits. With arc force greater than zero, the machine will decrease the current as the arc voltage (gap) increases; the rate of increase being dependent on the knob setting, and again the machine's electrical limits.

Here is a lengthy explanation from miller.
http://www.millerwelds.com/resources...rticle108.html
Mark gives an answer in another thread
http://www.everlastgenerators.com/fo...t-is-arc-Force
Ben Krasnow has a comment also.
http://benkrasnow.blogspot.com/2009/...r-welding.html

As a general rule, the settings should be at whatever position you find it easiest to produce an optimum weld.

Thanks for the links.. Ben says "when TIG welding, make sure it is all the way down". Maybe that's why I have a hard time on thin stuff....
I've started an arc and turned the knob and you can see the effects on the arc.
EDIT: I just tried to adjust the Arc force as I welded and didn't see a difference so maybe I'm crazy and it doesn't affect TIG!?!?

[parkour]

I have fiddled with the knob in tig mode just a bit.. but not enough to come up with anything concrete.
IIRC, Mark mentioned in another thread that arc force knob should not be active in tig mode.. only stick.... but it was in ref to someone asking about it in tig mode, and I vaguely recall the question suggesting that it was active.

If arc force functions in TIG mode, you should be able to see its function visually. As you know, the arc gets brighter with increased current, and less bright with reduced current. So set the arc force at zero, strike an arc, and adjust the arc gap. You should notice that the brightness is essentially constant. Now try again with arc force at max. When you lengthen the arc, it should get narrow and dim, and when you shorten the arc, it should get wide and bright.

[CGCINC]

If arc force functions in TIG mode, you should be able to see its function visually. As you know, the arc gets brighter with increased current, and less bright with reduced current. So set the arc force at zero, strike an arc, and adjust the arc gap. You should notice that the brightness is essentially constant. Now try again with arc force at max. When you lengthen the arc, it should get narrow and dim, and when you shorten the arc, it should get wide and bright.

This is exactly what I remember from the last time... I was in AC welding Aluminum and I swear I remember the arc getting wide and narrow depending on knob location. I think I'll just leave it in the middle since thats where it has been and it works fine.

[jerky]

sorry, though u were stick welding not tig welding.

[CGCINC]

sorry, though u were stick welding not tig welding.

No, that's good to know in case I do stick weld!