Subject: MIG QUESTION

From: [email-masked] (Gene H. Lichty)
Date: 3 Nov 1995 06:53:52 GMT

I presented this question earlier and got no response so will attempt
again.  I am now using a mix of 75%/25% oxygen argon for welding mild
steel.  Can a person use 100% argon for welding steel.  Would like to
have the capability of welding aluminum and steel without changing
tanks.  I know the argon is more expensive, but would just like the
convenience of one tank.  TIA!!  :<)

Geno

---

From: [email-masked] (JPErdman)
Date: 3 Nov 1995 19:20:08 -0500

I can't imagine that you're really using an oxygen/argon mix to weld with!
Or was that a test to see if we were paying attention. The whole idea of
MIG is to keep oxygen away from the weld. Molten steel in the presence of
oxygen does strange things  not the least of which is to burn off all the
carbon in the puddle and oxidize (read rust) the iron.   

I suspect that you're really using a 75/25 mix of carbon dioxide and
argon.

To answer your question.. Yes you can use pure argon as a shielding gas
for mild steel. My welders prefer it to the "Stargon" mixture (above)
beecause they are able to weld in close quarters and do it with a lot less
spatter (which is important in some of our work). 

And yes it is a lot more expensive than shielding with the mixture so we
don't do it all the time. We are big enough that we have several cylinders
of each around all the time. On our scale the pain of changing cylinder is
small compared to the amount of gas we consume in a week. So it pays to
change and use pure argon only when we need it.
John Erdman
Greenfield Machine Works     
Costigan, Maine
207-827-5557

---

From: glen a [email-masked] (glen ray)
Date: Sun, 5 Nov 1995 15:19:15 GMT

Hello Geno,
	I believe the gas mix your using is probably CO2 and argon.
You can run just argon. You can also run just CO2. I don't know how
well CO2 will work on aluminium. I never tried it. I used to weld 
Black iron in a "wrought iron" furniture shop. We used mig welders
with just CO2 and it seemed to work fine. Another alternitive is to
use the bottles of mixed gas. Your local welding supply should be able  
to suggest the best mix for your application. (One bottle with CO2 and
argon mixed together)
			Good Luck
                         Glen Ray

---

From: [email-masked] (Paolo Zini)
Date: 6 Nov 1995 11:19:06 GMT

>well CO2 will work on aluminium. I never tried it. I used to weld 

I tried. It dont work. You can see aluminum drops running around the
shop, but no welding not a poor welding absolutely no welding.

>to suggest the best mix for your application. (One bottle with CO2 and

I have found a "guru" of welding and it said me that argon is must for
aluminium.

Paolo
                            _______
                            TTTTTTT  
                            | | | | 
                          ===========
Paolo Zini                TTTTTTTTT
CNUCE institute of CNR    | | | | |
Pisa ITALY               ===========
[email-masked]      TTTTTTTTT
                         | | | | |
                        ===========
                        TTTTTTTTT
                        | | | | |
                       ===========