i would be very tempted to try copper weld through paint then clear it ,unsure about delam issues but its something i will be atempting ,this would give you a superb copper finish much like the chrome effect paints
the other way would be candy dyes over chrome effect but this would be an extremly expensive paintjob,i think there is a coppertone version available now maybe ven based on the copper weld through pigments
there are also copper pearls but they will not give the proper metal effect but could be very effective depending on the viewing distance
Paul