Auto Collision I - MIG Welding Theory

MIG

Metal Inert Gas - allows welding for high-strength steel, high-strength low-alloy, in modern cars.

GMAW

Gas Metal Arc Welding - technique that uses an electric arc between the electrode and the workpiece.

Zinc

Protective metal coating applied to steel to prevent rust and corrosion.

Galvanizing

To protect the steel from corrosion and rust

Root Gap

The deliberate space left between the edges of two components to be joined, typically a butt joint with a V-groove.

Penetration

The depth to which the welding heat fuses the base metal.

Electrode

The metal rod or wire that conducts electricity to create a metal arc.

OEM

Original Equipment Manufacturer - It is important that when repairing a vehicle, you repair it to the exact way it was originally made in the factory.

DC Reverse Polarity

Electric current flows from negative to positive in a circuit. The electrode wire is positive (+) and the workpiece is negative (-)

Amperage

The flow of electrical current to make the necessary heat to melt and fuse metals.

Bead

Raised lines of molten metal formed when two pieces of metal are fused together.

Stick Out

Aka Electrode Extension - The length of unmelted welding wire that extends from the contact tip of the gun to the workpiece.

Flux

The rubber coating on the electrode used as a protective shielding gas.

Masking

Covering parts of a vehicle to protect from paint overspray; to make a clean, professional finish.

Adjacent

Next to. In car repair, it's panels that are physically connected or next to each other.

Puddle

A small, molten pool of metal formed by the heat of the welding arc. It is the actual substance of the weld and moves along the joint as you guide the welding gun. Controlling the heat, travel speed, and technique (pushing or pulling the gun) is key to manipulating the puddle and creating a strong, high-quality weld.

Welding Work Clamp

Piece of equipment that completes the electrical circuit.

C-25

Combo of argon and CO2 shielding gas. Ratio of 75% : 25% respectively

Prep Solv

Wax and grease remover

CFH

Cubic Feet per Hour

Argon

An inert gas used for shielding

CO2

Carbon Dioxide. A gas used mixed with Argon for shielding gas.

Porosity

The formation of gas-filled cavities or voids within the solid weld metal, caused by gases like hydrogen, oxygen, or nitrogen being trapped as the molten weld pool solidifies. It can significantly weaken the weld, potentially leading to structural failure.

Duty Cycle

The percentage of time it can operate within a 10-minute period before it needs to cool down. For example, a welder with a 60% duty cycle can be used for 6 minutes continuously

Cold Start

When the initial weld bead doesn't properly fuse with the base metal, appearing as a blob or lack of fusion.

Weld-Through Primer

Zinc or copper-based coating applied to metal surfaces to protect from corrosion.

Burnthrough

When the workpiece is melted and creates a hole due to heat too high or travel speed too slow.

Dressing

Preparing the weld by grinding, sanding, and cleaning the bead to make the surface flush (or flat and smooth) with the rest of the metal.

Tack Weld

A small, temporary spot weld used to hold metal pieces in the correct position and alignment before the final, full weld is made.