Using 24K gold

if a pendant is cast in 24 carat will tumbling harden it sufficiently
for normal use? must it be tumbled, or is there a way to harden it
without affecting the surface finish? i would optimumly prefer going
from casting & cleaning to the extent neccessary, and then brass
brush by hand, but am concerned about it being too soft and easily
deformed. the piece is open work about an inch in diameter and
thickness of 1- 1.5 mm. thanks in advance.

april karavani
de-tech studio

You cannot do any significant work hardening of fine gold castings
period end of story. In fact gold presents little hardness increase
even with 80% reduction in thickness in cold working. Fine gold is
soft.