Materials
How hot and fast: amp and speed tips for cast iron
Quick answer
Low current for the rod size, many small passes — then set travel speed by watching the pool, not the clock: a consistent-width bead with proper wetting at the toes is the target on cast iron.
Starting numbers
Take the standard thickness-based amperage for steel and apply the material adjustment above. On cast iron, test coupons are not optional — set two or three parameter sets on scrap and pick the bead that wets in without undermining the edges.
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