Welding Arc Current Selector
A guide to help welders select the appropriate starting amperage based on electrode type, size, and welding position.
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Amperage: The Primary Control
Amperage (or current) is the single most important parameter a welder controls. It dictates the amount of heat going into the workpiece, which in turn controls the depth of penetration, the size of the weld, and the travel speed. Setting the correct amperage is a balancing act.
- Too High: An excessively high current will cause deep, uncontrolled penetration, potentially burning through the material. It can create a large, fluid weld pool that is difficult to manage, especially in out-of-position welding.
- Too Low: An insufficient current will result in a "cold" weld with poor penetration and a high risk of lack of fusion. The arc may be unstable and difficult to start.
Why Position Matters
As you move from the flat position to vertical or overhead, gravity becomes a major factor. To counteract gravity and prevent the molten weld pool from sagging or dripping, welders typically reduce their amperage by 10-15%. This creates a smaller, less fluid weld pool that is easier to control.