<VV> Re: Aluminum Tig Weldiing Advice

[Frank F Parker]

> characteristic that you want when working with thin aluminum.  Switch your
> ground electrode cable to the torch cable electrode lead on the power supply
> and switch the torch cable to the electrode lead.  Set the high frequency on
> to the continuous setting. Use a 1/8 zircon tungsten electrode and set the
> panel for maximum penetration, which will (in actuality) be maximum cleaning
> because of the cable reversal.  It will also concentrate more heat at the
> electrode and will help to eliminate the refractory oxide layer from the
> base metal and will focus most of the heat on the electrode minimizing burn
> through. A foot control (or hand amperage control) is essential as once the
> aluminum comes up to temperature, it is necessary to throttle back on the
> current setting to prevent melt through. Having remote current control is a
> good thing! Most power supplies do not offer sufficient cleaning action
> available on the panel. This is why I recommend the polarity reversal with
> the cable as we are fooling the welder to give us the best electrical flow
> characteristics on thin material. Frequency is not as critical as the
> polarity reversal. Set the balance control on 90 % penetration.
>
I think there may be a little confusion on how I presented the info to
you. I do not think I have to reverse the weld leads to have current flow
from work to torch for additional cleaning and reduced heat to work piece.
That is what we want but if I read the manual for the welder correctly (a
highly adjustable model), the balance control does the switching for me.
The normal setup for TIG of steel with DC welding has the torch connected
to the neg out of welder and "gnd" clamp to the pos outlet giving you a DC
straight polarity setup with electrons flowing from torch to work. This is
with balance in center or 50% direction.
If you you lower setting of balance, you increase the positive portion of
the AC waveform and electrons flow from work to torch yielding more
cleaning as less heat to the thin aluminum work.

Have I misunderstood the controls. The manual says if balance is made more
positive at greater than 50%, the you get flow from torch to work and more
pentration. So it seems you do not need to reverse the leads???

regards,

frank