Material and surfaces.
Limitations may appear on metals that aren't ferrous.
Corrosion can appear on ferrous metals.
It has only been performed on a sheet of 8.7 x 8.7 cm.
It is not guaranteed to his finish be applicable to larger sizes.
It can only be applied to smooth surfaces.
Material pretreatment.
This finish is only achievable by oxidation, making it prone to corrosion.
Protection coating.
Permalac protection slows down the aging of the finish but highlights imperfections that are not apparent to the eye.
Cleaning and maintenance.
This finish must be cleaned with a dry, absorbent micro-fiber cloth.