<VV> Re: Aluminum Tig Weldiing Advice

[Garth Stapon]

Frank:

There are differences with each manufacturer.  Most offer a greater amount
of control on the penetration side - say 70% penetration / 30 % cleaning.
If you have a 50-50 unit, set it so that you have maximum cleaning action
when welding on thin aluminum. You actually want less penetration to control
melt through.

If you have a 70/30 style unit, reverse the lead and set it at full
penetration.

Good luck....



----- Original Message -----
From: "Frank F Parker" <fparker at umich.edu>
To: "Garth Stapon" <stapon1 at earthlink.net>
Cc: <virtualvairs at corvair.org>
Sent: Sunday, March 06, 2005 5:48 PM
Subject: Re: <VV> Re: Aluminum Tig Weldiing Advice


> > 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
>
>