Welding Calculator
Getting the right welding parameters is the difference between a strong, clean weld and a messy, weak joint. This calculator provides recommended amperage, filler wire or rod diameter, shielding gas flow rate, and travel speed based on your material thickness, joint type, welding process, and base metal.
The fundamental rule for MIG welding mild steel is 1 amp per 0.001 inches of thickness. A 1/4-inch plate needs approximately 250 amps. TIG welding uses slightly less current, and aluminum requires higher amperage due to its higher thermal conductivity. These are starting points; fine-tune based on your specific machine, wire feed speed, and joint fit-up.
Filler wire diameter should match material thickness. For MIG: use .023-.030" wire for sheet metal (up to 1/8"), .030-.035" for medium plate (1/8" to 3/8"), and .035-.045" for heavy plate (3/8"+). For TIG, common filler rod sizes are 1/16", 3/32", and 1/8". Using too large a filler for thin material wastes heat and distorts the workpiece.
Shielding gas protects the weld from atmospheric contamination. MIG welding steel uses 75/25 argon/CO2 (best all-around) or 100% CO2 (deeper penetration, more spatter). TIG uses 100% argon for all metals. Aluminum MIG uses 100% argon. Gas flow of 25-30 CFH is standard; increase in drafty conditions, decrease in enclosed spaces.