<VV> welding

[Garth Stapon]

Phil:

Pulsed Mig is a spatter free variation of Mig welding. You need a minimum of 
300 amps output, but 400-500 amps is better.  It permits the use of larger 
diameter wire (less money) and can keep welding fume on aluminum, steel and 
stainless to an acceptably low level.

There are two current levels with this technology, the peak and back ground 
current.  Peak current is typically set at 300-400 amp range and back ground 
is set at 40-60 amp range.  The current levels cycle between the high and 
low current to provide a smooth transfer of the metal droplet into the weld 
pool. (You do short arc welding with your small Mig) Incidentally, I gave a 
paper at the American Welding Society National Convention in Dallas this 
year and used some high speed arc cinematography to illustrate the pulsed 
metal transfer mechanism. The file is very large so its not something that 
can be e mailed.

The best way to put this is that Electric Boat (down the street from here) 
uses pulsed Mig to weld nuclear submarines.  Those that are familiar with 
conventional Mig welding realize that lack of fusion is a big issue with an 
improperly set system and could also be an issue on materials that are 
thicker than 2.0 mm.

Computer control has made the new pulsed technology more user friendly and 
these systems are now more affordable than ever. It's kind of like Mercedes 
developing ABS and now its available on a Hyundai.

With respect to welding aluminum with your system, the issue that you (and 
everyone else that tries to weld aluminum with a less costly Mig system will 
experience) are wire feed issues. Feeding aluminum wire is like pushing a 
wet noodle. You need a spool gun as a minimum but if you want to get serious 
a push pull style feeder is required. That costs money.

I did not even touch on shielding gases and their impact.

I hope this helps.
----- Original Message ----- 
From: "Philip Alotis" <alotis at comcast.net>
To: <virtualvairs at corvair.org>
Sent: Thursday, June 02, 2005 5:49 PM
Subject: <VV> welding


By the way Garth,

Do please tell me (us) more about pulsed mig welding for Stainless and 
Aluminum.

My little Lincoln SP175 + seems to work just fine on Stainless and Aluminum
(though I usually use TIG  for these) but perhaps I just don't know what I'm 
Missing.
Like I said before, my Welding knowledge is a little dated.



Phil


P.S. Is it true that the new inverter type TIG welders weld Aluminum with a 
pointed electrode?
 _______________________________________________
This message was sent by the VirtualVairs mailing list, all copyrights are 
the property
of the writer, please attribute properly. For help, 
mailto:vv-help at corvair.org
This list sponsored by the Corvair Society of America, 
http://www.corvair.org/
Post messages to: VirtualVairs at corvair.org
Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs
 _______________________________________________