MIG welding is an ideal tool for welded metal sculpture. MIG stands for metal inert gas. Not to be confused with TIG (tungsten inert gas) welding which I'll talk about in A TIG welding post. The M in MIG stands for metal. The metal is stored on a roll usually located in or at the machine power source and is fed through a liner to the mig gun. The MIG gun has a trigger on it which when pulled actuates a small motor with rollers on it that feed the wire through the liner and out the gun nozzle. The trigger simultaneously opens a solenoid that allows the inert gas to flow out the nozzle end where the wire exits and weld takes place.
In MIG welding the emphasis is on the metal wire which has two main functions. One is to feed a continuous supply of filler metal that gets consumed and deposited at the weld in the welding process. Two it carries the current for the electrical spark and amperage to heat and melt the metals together.
The wire feed speed and amperage controls are set in accordance to metal thickness, wire thickness, weld penetration and wire feed speed desired.
With non-flux core welding wire the ground cable is negative and is clamped onto the work piece to be welded on. When the trigger on the welding gun is pulled the wire feeds out and makes contact with the metal. The electrical current wants to be complete but the high amperage and thin wire cause the wire to melt immediately on contact. The electrical current is so strong it even penetrates into the metal. This melting and penetration act to gouge the metal and fill in with the feeding wire causing a weld to be produced bonding the two separate metals as one.
The inert gas has a roll of isolating the weld area from oxygen. If the inert gas was not flowing out of the welding tip the oxygen at the weld area would cause the weld to be contaminated and result in poor weld penetration, air bubbles in the weld and unsightly weld spatter. The Inert gas is one of the crucial components to allow for a smooth and solid weld.
Oxygen and acetylene, otherwise known as oxyacetylene welding is the most common form of welding i do to create my small welded metal figure sculptures. Its very versitile and i can achieve both small and large welds. I can also heat, forg bend and cut the metal parts i'm working with.
Here you can see a set of large ears i sculpted out of bicycle sprockets.
A blog on my sculpture and sculpting process.