I need help understanding Transfer type when Mig welding?

[CGCINC]

My main question is:
Don't you just set the Mig voltage to the thickness of the metal being welded and let it fly?

I've read about the different Transfer Types....Short circuit, Globular, Spray, Pulsed spray.... But I just don't get why you need to worry about what type of Transfer you are doing as long as the voltage is set right and you have proper penatration?

[kenwhite]

For your IMIG-200, you will be doing short circuit, which is really all you need. Each transfer type has advantages and disadvantages, but will also require different gas mixtures and current profiles or levels.

EDIT: Here is a good download -> http://www.praxair.com/praxair.nsf/0...ILE/P-8126.pdf

[CGCINC]

For your IMIG-200, you will be doing short circuit, which is really all you need. Each transfer type has advantages and disadvantages, but will also require different gas mixtures and current profiles or levels.

EDIT: Here is a good download -> http://www.praxair.com/praxair.nsf/0...ILE/P-8126.pdf

Thanks for the download.... Seems there's more to Mig than just pulling the trigger!

In that downloadf it says...

In a gas blend of at least 80 percent
argon (see Figure 5), the electrode
metal transfer changes from globular to
spray mode as welding current increases
for any given electrode diameter

I see a lot of people using a 75%/25% Argon Co2 mix but in this download for welding low Carbon steel, the lowest amount of Argon the show is 80%.
Should the mix be 80/20 instead of 75/25? I'm not sure if you can specify the mix you want at the welding store or you just get what they have?

[zoama]

Performance (Mark) say he uses C18 which is 18% C02 and the balance argon. He says in gives less BBs. I'm gonna give it a try when my current tank is empty.

[CGCINC]

I'm going tomorrow to get a bottle so I'll see what they can do. I might do a 80/20 and see how it goes..

[CGCINC]

Another question about Transfer Type was:

Is it something you change on purpose and for a reason, or is it something that just happens as you lower/raise voltage and wire speed?