Chrome plating on ABS: same thicknesses as on metal?

Can anybody tell me if the plating thickness (microns) on ABS parts will be more or less than the plating thickness on Alloy parts? I have a specification for metal and I am thinking of using the same spec for my ABS plastic parts.

Hi, Graham.

I wouldn't do that. Plating on ABS has thermal expansion issues that you don't have on metal, so chrome plating onto ABS usually incorporates a substantial layer of copper plating which is usually omitted in plating onto steel.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Graham,
It is not clear what your plastic components will be used for, but I suspect the chromium is purely decorative. Ted is correct about the copper interlayer, so I would suggest you metallise your ABS in the conventional way with either nickel or copper and then thicken it up with 5-10 microns of nickel or copper, followed by a decorative flash of chromium. You may prefer using nickel to copper, as it will not be so obvious if the chromium is very slightly discontinuous.