I learned to weld about 30 years ago and did it almost on a daily basis for over 20 years.
There are 3 types of electric welding, each has its advantages and drawbacks, and some types
are better suited for particular applications than others.
Stick welding, uses a flux covered rod, the flux burns and produces a gas cloud to shield the
molten metal from oxygen. It produces smoke, slag and spatter. you can stick weld with AC,
DC or DC reverse polarity. most cheap welders reffered to as "buzz boxes" are AC.
Stick welding is good for welding thick material, hardfacing and general purpose fabrication.
Flux coer, is a type of stick welding, the wire contains a flux that burns and provides the shielding gas.
It produces smoke, slag and spatter. it is used for general light welding.and does not have much advantage over sticks.
MIG welding uses a consumable wire electrode shielded in an inert gas. It is cleaner than stic or flux core but produces
speatter. It is best suited for production welding such as fabricating or building up shafts etc. The drawback for small
work is that it is not precise andanot as controllable as TIG. with the wire constantly feeding it does not lend itself to
small precise work.
TIG, uses a Tungsten electrode to produce a precision arc in a gas bubble. It is clean, and precise. Yiu have total
control over penetration and the amount of filler to add to the joint. To TIG weld an arc is started and a puddle of metal is made,
filler is dipped into the puddle and then the torch is mover forward. the filler rod can be used as a heat sink to control the
puddle so total control over the weld is easy. there is no smoke, slag or spatter.
there is less cleanup when you are done and it is easier to control the amout of warping and distortion from the weld.
Since there is no slag, you get good clean solid welds with no voids or porosity.
A few tips,
1. get good soft thin leather gloves to weld woth.
2. welding lens choice is important. there are 3 types of lenses.
1. straight tinted lens, these are cheap, but have a drawback in that you can't see any color so it is harder to
get a good weld with sticks or flux core.
2. gold coated tint, these are the best, they allow you to see color so it is easier to get a better weld as you can see more detail.
3, instant dark, they are high tech, use batterise, are expensive and you can't see color
They are nice when you are starting the arc, but not much better than a plain glass when welding.
For gunsmith work TIG is the best, Yes it is possible to use the other types but they don't do as good a job
as a TIG.