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Mig Welding Repair:

Personal Safety Precautions:

  1. Fumes and / or gases can be a health hazard.  Use adequate ventilation
  2. Avoid the grounding of any exposed electrical wiring to avoid shock
  3. Wear protective eye and body equipment.  The arc rays can burn eyes and skin.
  4. Avoid the hot slag and / or sparks to prevent fire / burn hazards

Personal Safety Equipment:
Welding helmet or welder face shield, safety glasses, gloves, proper foot protection and coveralls. 

Mig Welding Equipment:
Consist of 160-volt single phase 20 amp direct current (DC) power pack with a wire control feeder system, carbon steel welding wire spool with a wire diameter of  ".035" and an insulated, hand-held welding tip with wire feed control trigger, grounding clamp, and a tank of compressed carbon dioxide gas.

 
 
Mig Welding Equipment Setup:
After connection the grounding clamp, power source, welding wire, and compressed CO▓ tank, the power pack is then switched to the "on" position.  At this time, welding temperature and wire feed can be adjusted to proper setting for correct wild penetration.  A piece of scrap metal with the same thickness as the stock to be welded can be used to determine the weld penetration.  Weld penetration should be as close to 100% of the stock as possible.

Weld Penetration:
Weld penetration is achieved when the welding wire and the chosen stock, or material to be welded, have been heated to the point of molecular cohesion.  This means that the welding wire and the desired stock have been heated to a point when they combine to form a single unit, or "fuse".  The molecules of the metal stock and the welding wire have completely combined together.

Positioning:
Correctly locating the part or component to be welded.  Must be positioned correctly the first time, the part cannot be moved after it has been welded.

Clamping:
Holding parts together.  Can be hand clamps or C-clamps.

Tacking:
Applying a small spot of weld to hold the part or component.  Once the small tack weld has been made, part location can be checked for correct location and fit prior to finish welding.

Caulking:
Hammering down the metal before and after it is welded.

Welding:
Joining two pieces of metal with an even bead, making sure there is good weld penetration into the base metal.

Heat:
The heat setting will vary with different thickness of metal, and must be set properly so the weld does not burn through the metal, creating a larger repair.

Wire Feed:
If the wire feed is not set at the proper speed, relative to the heat, a poor weld will be the result.  When the feed is too slow, cold weld build-up will result.  When the feed is too fast, splatter will result.

Gas Pressure:
Gas pressure must be set properly to achieve a good weld.  It must have the right amount of CO▓ to protect the molten metal.  The CO▓ gas actually starves the weld of oxygen which decreases the temperature of the weld, assisting the weld in achieving proper penetration.

Mig Welding Process Procedure:
When all preliminary steps of the welder setup, stock position clamping and caulking have been achieved, actual welding can begin.  The metal insulator covering the tip of the welder may be held directly against the metal stock to be welded, or to view the weld as it is created, the welding tip can be tilted to an approximate 45 degree angle to expose the welding point.  Depressing the control trigger initiates the wire feed,
CO▓ gas flow, and wire arc ignition.

For Spot Welding:
The welding tip is held in a single position as the welder is activated, until the desired penetration is achieved.

For Bead Welding:
The welding tip is drawn slowly backward as the weld is activated, allowing the weld to "pool" or "puddle" into a continuous form.  Weld penetration should also be properly maintained in bead welding.  When the desired length and depth of the weld has been reached, the wild is complete.


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