Welding Question and Answer

Question
I have never welded before in my life and I know no one that can show me tips/tricks/how.
I am ready to visit the library and read how-to weld. Before I do that, I would like to focus on a specific type of welding. I know there are ARC Welders, MIG Welders, etc. What is the difference? Which is best for certain jobs?
I know there are different types of welds too (IE Spot welds, etc).
That's it. That's I know. I am a good mechanic so I do alot of car engine work and want to start doing some body work which will require spot-welds and welding in some patch panels.
Can you point me in the right direction? Any advise would be appreciated. Thank you!

Answer
Well that is a bit of a BIG question.

Lets start with the basics.
Any welding process that uses electricity to melt the metal is technically "arc" welding.
The term "Arc welding" usually refers to Stick welding or more accurately Shielded Metal Arc Welding (SMAW).
This process is the most cost effective and versatile of welding processes.
Equipment doesn't have to cost very much, and it works outdoors, but it does take quite a bit of practice to get good.
A steel wire electrode, usually around 14 inches long, is clamped by one end in an electrode holder.
The other side of the electric circuit is supplied with a ground clamp that is attached to the metal to be welded.
The electrode is a steel wire coated with a flux.
The flux will burn off as you weld, and will provide a shielding atmosphere to protect the molten weld pool.
The flux residue will solidify over the cooling weld as a slag layer that can be chipped off after it cools.
Always where safety glasses when chipping a stick weld or you can get bits of flux in your eye.
A 200 amp stick welder costs under $400.

MIG welding is a process that uses a large spool of wire to act as the electrode/filler.
The wire is fed from the cabinet by a wire feed motor, out to the gun through the middle of the stinger or gun cable.
The trigger on the gun activates the wire feeder, the power contactor, and a gas solenoid.
The gas solenoid controls your shielding gas, usually a mixture of Argon and CO2.
MIG is the easiest of all welding processes to learn.
It is basically a hot melt glue gun for steel.
Point the gun, pull the trigger and weld.
It works very well for building from clean new steel in a shop.
Very fast, and clean.
MIG is limited to indoors, or your shielding gas will be blown away.
You can use a Self Shielding Flux Core wire in place of solid steel wire.
This Flux Core wire will provide it's own gas as it burns, and will work outdoors, but burns very hot and is harder to use on thin sheet metal.
MIG machines start around $500 and climb from there.


TIG is the most precise of the standard arc welding processes.
TIG uses a tungsten electrode held in a torch.
An argon gas shield protects the tungsten.
An arc is drawn from the tungsten to the base metal.
A foot pedal controls your amperage so you can very accurately control how much metal is melted.
Filler metal is added by hand.
TIG takes the longest to learn but is the best process for building bike, motorcycle, airplane, or race car frames from thin wall tube.
TIG machines start around $1000.

There are several decent video series available for Weld training, from Miller, and Lincoln.
Nothing beats a live teacher.
Check your local community colleges to find an evening welding program.
This can get you basic training and exposure to all the welding process to see which works best for you.
You can also call around to local fabrication shops to see if any of the welders do private tutoring.

I can't really type an entire welding manual into this post.
Just remember to buy good safety equipment, and watch your puddle, not the arc.

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