AC means the flow of the electrical current changes direction back and fourth. See green line in image above for reference.
AC welding is a cheaper and less used than DC, that being said AC welding is great for welding Aluminum.
- Welds aluminum very well, Higher temperature abilities
- Cheaper machines run only AC
- No Arc Blow
- Unstable Arc
- Welds normally appear less smooth
DC is when the electrical current continues in one direction. See red line in image above for reference.
Direct Current welding is most common for all weld processes including Stick, MIG (GMAW- Gas Metal Arc Welding), and TIG (GTAW- Gas Tungsten Arc Welding). The constant flow of current allows for a smoother overall weld process.
- Welds will appear smoother due to the constant current flow
- More stable arc that allows for easier welding
- Less spatter
- Arc Blow
- DC Welders are more expensive
- Cant be used to weld Aluminum