Cole Harvey wrote:
>
> Hi all,
>
> I am considering buying a MIG welder. I have used my father's MIG Miller
> welder with gas (CO, I think). I did some pre-shopping and found that gas
> is about $200 more. What is the gas for, and do I need it for small body
> panel repairs? Also, what does MIG and TIG stand for?
>
> Cole
Cole:
The abbreviations MIG (GMAW) and and TIG (GTAW) stand for
"Metallic-Inert Gas" and "Tungsten-Inert Gas" welding. The purpose of
the gas in both types is to provide a shield to protect the weld metal
from the air. In one type of MIG welding, a flux-cored wire is used to
replace the shielding gas by a gas-shield formed from the burning flux
in the core. This is actually the same as "stick" (SMAW) welding where a
flux is used on the outside of the rod to provide a gas shield over the
arc, except that a wire feeder is used instead of individual rods.
The advantage of using shielding gas (now usually a carbon dioxide-argon
and other gas mixture which gives better results than straight CO2) is
that you will have a hotter, steadier, and cleaner arc with virtually no
clean-up. This is much better for body work than the so-called "gas-less"
type of MIG welding, unless the work is to be done outside and on
thicker metal. The extra $200 is for a built in gas valve and a flow
meter, but is well worth the money since it actually gives you full MIG
welding capability and allows use standard MIG wire (cheap!) rather than
flux-core wire (expensive!).
Ron Tebo
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