What colour to use to simulate paint chips on panzer grey?

Thanks in advance
Karl

Kark;

I'll presume that you mean Dunkelgrau RAL 7021 - the standardized German paint color and scheme for all AFV from Aug 01 1940 to 18 Feb 1943.

The basic answer to your chip question is...

Chipping away the dunkelgrau should usually reveal the underlying rot-oxide primer commonly applied to armored vehicles during manufacture and before they were base-coated. Chipping would also presumably reveal some underlying naked / later rusty metal, if said chips were something like bullet strikes, etc.

As a note:

Best of my understanding...

All new production vehicles were factory-painted in RAL 7021 starting from before the Aug 1940 regulation - 1937 paint scheme regs specified factories painting and issuing new vehicles to units in the dark gray #46 (re-named and specified as RAL 7021 in Feb 1940) - the units then bought and applied the specified 1/3 coverage secondary brown per 1937 regulation on their own. In June of 1940, units were henceforth instructed to no longer purchase the brown paint ... resulting in newer vehicles remaining dark gray only. This was formalized as the new "dunkelgrau RAL 7021 only" painting regulation from 01 AUG 1940.

IF you instead "do" one of those current / on-hand vehicles re-painted starting ca April 1941 for shipping to north Africa, you are talking about dunkelgrau vehicles over-painted in one or another "sand" shade tropical color(s). New vehicles destined for shipment to Africa started getting tropic paint colors applied at the factory from later 1941. I mention this because one might consider chipping away the "sand" on an earlier 1941-shipped "re-painted" panzer to reveal dunkelgrau and perhaps tor-oxide beneath that. Whereas a later-painted 1942+ Africa vehicle may not have any dunkelgrau to reveal - the chipping would reveal rot-oxide.

Per your query; an original dunkelgrau vehicle should chip to reveal rot-oxide red and metal.

Cheers!

Bob