Materials
How hot and fast: amp and speed tips for aluminium
Quick answer
More current per mm than steel (40–55 A/mm TIG) — aluminium dumps heat into the job — 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 aluminium.
Starting numbers
Take the standard thickness-based amperage for steel and apply the material adjustment above. On aluminium, test coupons are not optional — set two or three parameter sets on scrap and pick the bead that wets in without undermining the edges.