Andrew,
Painting metallics on resin:
1- After priming the figure, I give the metal areas a couple of coats of acrylic black.
2- I apply a mixture of Gunze Sangyo 50% iron and 50% aluminum, apply with a
smooth brush.
3- when completely dry, brush on a coat of black oil paint, and let it sit for about 10 minutes.
4- wipe of the excess black oil paint with a soft tissue or cloth.
5- when that is dry, start delineating with a size 00 brush using black.
6- high light with luco silver powder.
hope this helps.
Cheers
Roc