Ray and Pat,
Concerning MIG welders I have the following info.
I have a Lincoln SP-100 that I have used for both flux core and MIG (metal
inert gas). It works well both ways. The only difference is that flux core
provides the shielding gas when the flux burns up while welding, whereas the
MIG shielding gas comes from the argon. The flux core does leave some slag
that cleans off easily whereas the MIG does not, so the MIG is less work from
that point. The only problem with the smaller amp welders is penetration in
butt welds (or any welds for that matter). To weld 1/8" mild steel with a
butt weld, I usually do both sides to ensure good penetration. I would
recommend a minimum of 150 amps, I got tired of messing around and bought a
nice ESAB unit at 250 amps that does everything I want. (The local BMW plant
tried all the different units and decided on the ESAB, and I have been
pleased also) But as you might expect, I paid for it! I would have no problem
with either a miller or lincoln unit.
>My impression is that flux core welding works ok, but the
weld has to be cleaned very carefully afterward. I would worry about the
effect of any flux or slag that was missed on the paint. I think also
that the gas helps localize the heat. <
Cleaning the slag is no big deal, stick welders do it all the time without
any difficulty. As far as I know, the shielding gas does nothing to localize
the heat, it only protects the weld from interacting with the atmosphere. But
by changing the mixture of the shielding gas, the penetration characteristics
of the weld can be changed.
The big advantage of MIG is for production work. No slag to clean, no
electrodes to change.
Take care,
Ed
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