In a further preferred embodiment of the present process, the metal sheet, in particular aluminum sheet, is uncoiled and first coated with a primer (such as PMW 0632 obtainable from Valspar Corp.) with a dried film thickness of 0.0004-0.0006??? and then a layer of Valspar PMW 1494 (obtainable from Valspar Corp.), with a dried film thickness of 0.0095-0.001??? that is subsequently heat cured to ens