How to choose welding rod amperage

You will notice that the amperage is not the same for each type of welding rod of a certain diameter. That is because the flux coatings on different welding rods react differently under different currents.

A good starting point for setting your amperage is to choose an amperage in the exact middle of the range for a horizontal fillet weld. For example, a 1/8″ 6011 rod would be 100A at its middle amperage. Welding around this amperage should give good fusion, no sticking and not too much heat. Then from this point you can adjust based on the following variables.

Base Metal

• For thinner base metal use lower amperage
• Thicker base metal use higher amperage

Welding position

• Overhead position you should lower the amperage by 5% (and a thinner electrode)
• Vertical-up position you should lower the amperage by 10% (and a thinner electrode)
• Vertical-down position you should increase the amperage by 10%

Joint Type

• Decrease the amperage by 10% for butt welds.
• Decrease the amperage by 15% for corner joints

Current

• Increase the amperage by 10% when welding AC

Temperature

• Decrease the amperage if the base metal is hot
• Increase the amperage if the base metal is cold