<VV> Re: Aluminum Tig Weldiing Advice

[Garth Stapon]

Frank:

Thin aluminum material is difficult to weld.

Use argon shielding gas at a minimum flow of 20 cfh.

Most AC Tig welders with balance control focus on penetration which is not a
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.

Please note, you have to switch the polarity back to the original setting
for DC welding.

Use a dedicated stainless steel brush to physically remove oxide in the weld
joint area prior to welding.

Here is a paper that I co-authored on the topic of aluminum welding.

I hope this helps.

LATE POWER GLIDE SEDANS RULE
----- Original Message -----
From: "Frank F Parker" <fparker at umich.edu>
To: "Garth Stapon" <stapon1 at earthlink.net>
Sent: Saturday, March 05, 2005 10:24 PM
Subject: Re: <VV> Re: Free Weldiing Advice


> > Feel free to contact me off line if you wish to discuss your
application.
> > Regards,
> > Garth Stapon
>
> Garth,
>
> I would like to take you up on welding advise specially TIG welding
> aluminum. Plate is OK but have hard time joining 2 pieces of thin wall
> mandral bent tubing.
>
> I know cleaning is critical and close fitting parts helps other wise tends
> to burn holes.
>
> I use a HTP Invertig 201 ac/dc tig welder which has freq adjustable from
> 20-200HZ, balance from 10-90%, and can pulse from 0.4 to 2Hz in ac mode.
> See www.usaweld.com for info on welder.
>
> I have some green stripe tungsten and higher freq near 200 seems to help
> but uncertain about balance or to try pulse mode.
>
> Any suggestions appreciated
>
> regards,
>
> frank parker
>
>