Bruce,
An arc welder is a stick welder. You clamp an electrode in a holder and
strike an arc between the electrode and the work. The electrode is consumed
as you weld and you must keep the end of the continuously shortening
electrode a constant distance from the work. When the electrode is consumed
you must stop and insert a new electrode in the holder before continuing.
The electrode is coated with a flux. This flux burns to form a fume cloud
which protects the weld from contamination during the welding process.
Components of the flux form a slag which covers the weld bead and protects
it from contamination while it cools.
A MIG (Metal Inert Gas) welder is a wire feed welder. It uses an arc but
instead of using a stick clamped in an electrode, there is a spool of
wire which is fed into the work by a power feed. You don't have to stop
to change electrodes. There is a nozzle which flows a protective cloud of
inert gas (argon, nitrogen) over the bead as you weld. There are wire feed
welders sold without the inert gas. In this case, the wire must have a
coating or core of flux to protect the bead. Without the shielding gas it
is technically not a MIG though they are often still called that.
I am taking a welding course right now at a local technical college.
I have only done arc welding so far. The second half of the course will
be gas welding, cutting and brazing. They also offer a MIG course which
I expect I will take. I have never welded with a MIG so I can't give you
my first hand experiences but my instructor has told us that if we only
buy one welder then the MIG is a good choice as it is very versatile.
One of the reasons that I decided to take welding instruction was to get
experience on the different equipment so that I could better decide what
I would want to use for a restoration. The other reason was to get plenty
of practice on scrap steel so that I don't completely botch my first
restoration. (no guarantee that it won't still happen! 8^)
Can anyone else relate their experiences with a MIG?
-Bob Leger
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