# Another Very Basic Mig Question.



## Lood (May 27, 2015)

I recently bought a Matweld MIG 250Y machine: http://www.arcwelders.co.za/matweld-mig-250y-multi-process-mig-tig-mma-welder/

 I've been doing normal arc welding for years, fixing things on the farm, but this is my first MIG.
I realize that this machine is not in the league of the bigger brand names like Miller, etc, but I reckon it's good enough for what I intend to use it for. 
On my machine, there are adjustable controls for Amps, Volts, WFS and Pulse control. 

A friend of mine, who happens to have an identical machine, apart from his machine not having the pulse control, advised me that I can turn the Amp setting to zero while doing MIG welding. According to him, only the Volt setting is used with MIG, while the Amp setting is only used when doing normal stick welding.
I did this and I actually didn't realize any difference between the initial 180 odd Amp setting and 0, while doing MIG welding. However, on the Miller app, and in just about all other sources that I've read, an Amp setting is given, together with the normal Volt and WFS settings, when determining machine settings for a specific metal thickness?

I would appreciate some opinions and advice on this, please.


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## gr8legs (May 27, 2015)

Your friend is basically correct but may be interpreting the data wrong.

Where there are amps there are always volts - you can't have one without the other.

The welding processes differ - MIG is considered a 'constant voltage' process and MMA (SMAW) is a 'constant current' process, meaning those are the main factors affecting the welding process. 

Most MIG-only machines have two settings - voltage and wire speed. Most 'stick only' (MMA) machines have only a current control. In either case the missing parameter is determined by the power source characteristics and is not a useful operator setting. A multi-process machine's multiple (and sometimes conflicting) controls may or may not affect all the parameters depending on which process is currently selected. 

Sounds like you have a very versatile welding machine there. Very nice!

Stu


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