You didn't mention what hopper your painting but I do RC cars and have found out the hard way that the only paint that will stick to polycarbonate bodies is Testor's Pactra.
It is specifically designed to bond to that plastic.
Testor's other model paints do not stick.
Krylon flakes off.
This stuff does not come off and my cars are upside down almost as much as they're rolling.
RCs are painted from the inside but the bodies flex and crash and the Pactra stays on.
So if I were to paint a Halo, thats what I"d use.
They're expesive at $6 a small spray can.
Tamiya makes some in flat colors for their tanks and such.
Find out what your shells are made of and go from there.
Last edited by Target; 01-03-2013 at 07:17 AM.