At 02:40 PM 1/21/98 Jim wrote:
> I have a neighbour who's upgrading his shop and has offered to sell me
> his TIG welder. I don't know the price yet. It's a 120 volt light duty
> model which appeals to me for now. I asked what the difference was
> between MIG and TIG, and he told me that MIG is for aluminum and TIG
> is for steel. May he have said that backwards?
> If it turns out that what he's got for sale is really for aluminum I
> don't want it, so could someone let me know the real scoop?
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Jim,
The real difference is in the method of welding, not what can be welded.
TIG welding is done by feeding a "stick" into the arc created by carbon
electrodes. The arc is modulated by a foot control, and the arc is
"shielded" with a gas, usually argon. This is by far (at least in my
opinion) the best of the electric welding techniques, because it affords
much more flexibility, and if done properly the welds are works of art!.
You can weld (with a good one) very thin sheet metal (like aluminum foil!!)
that's difficult, if not impossible to do with a MIG welder. It's also
much easier to switch between metals, like steel to aluminum with a TIG
welder. The big disadvantage (for most of us hobbyists) is the cost of the
unit. Also its slightly more complicated than MIG in that you have to
control the welding arc (with the foot control) and feed in the rod (like
gas welding) so It's kind of like arc/gas welding combined. I wish I had
one but the cost keeps it from me. I have a gas welder (oxy-acetylene) ,
and a gas shielded MIG, plus a spot welder, so I really can't justify
another welder :-). MIG on the other hand is a "wire fed" arc welder that
you basically point and weld with (after setting it for the material you
are using). Use a gas shielding bottle (the flux wire works, but you still
get spatter, and ugly welds) and switching to aluminum requires you to use
a different wire, and change the gas bottle to a different type of gas.
Its also more difficult to weld very thin metal with a MIG, because of the
lack of control that the TIG offers. They will both weld pretty much any
metal that can be welded, but the TIG is better for some exotics (like
stainless). Both these are good candidates for thicker (1/4 inch or more)
metals than a gas welder, but for thin sheet (floors), or tubing,
(headers), with my equipment, I prefer the gas welding, as it affords a
little better control -
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