Definatly get a different gas. While argon will work for MIG, and is
required in some applications (alum), it's not a good general purpose gas.
CO2 is the cheap variety of general gas, but using 75/25 mix (argon CO2 mix)
will usually produce a better looking weld (less spatter). Welding 16ga
with that thick of wire will usually require pretty low settings, and you'll
have to move right along to prevent turning your welding into a hole maker.

--
Lynn "I have opposable thumbs, and I'm not scared to use em" Amick
http://www.amickracing.com

"Constant Velocity" wrote in message
...
I just bought an ESAB MIG welder from a friend of mine who was using
it for Aluminum. It's the first MIG I have owned and I have a question
about the shielding gas I should use. The machine was sold to me with
a bottle of pure Argon. I'm going to be welding mostly mild steel, and
read somewhere that for arc stability on thinner materials I should be
using an Ar, CO2 mix. The other day I was trying to weld 2 pieces of
16ga sheet steel with .035 wire and couldn't keep the weld from
blowing through the metal. No matter how I adjusted the machine I
couldn't get it right. I assume that it is partly my newness with this
machine. I was having trouble maintaining an arc at amperages low
enough to keep from blowing through. When the settings were low enough
to keep the metal from holeing I got almost no penetration, and very
tall (rabbit turds) beads. Would switching to a CO2, Ar mix help? I
get great welds on ¼" with this current setup.

Thanks

Peter-