Mirror finish on ABS plastic

A. Hi Brian. You're a little vague on what you want and why, Brian. Chrome plating can be mirror bright, but are right that it is not a highly reflective surface for optical purposes. You can plate with rhodium instead of chromium for a more reflective material, but rhodium is a precious metal, so it may be cost prohibitive. Vacuum metallizing with aluminum is a reasonably inexpensive method for high production--for example flashlight reflectors.

A. Chrome or vacuum metallizing will not work if plastic has imperfections on the surface. It is absolutely necessary to start with a plastic surface as close to a mirror as possible. This is achieved by the mold or die and an accurate process control during molding to avoid flow lines, warpage, scratches, etc.

A. If you do not have highly polished mold, you have to use an organic coat over ABS before aluminum vacuum metallizing. It is done by many companies in the reflector coating business.

A. Hi John. It would be best if you could expound upon your own application because every situation is different and we readers may leave out both the cautions and the applicable quick tips when we don't know how your situation differs from the example you quoted. But such reflectors usually involve a three step process of an organic leveling base coat, followed by a metallizing step, followed by an UV stabilized organic topcoat to protect the metallizing.

For high production like those mirrors, the metallizing is probably aluminum metallizing done in a vacuum chamber.

Lower production needs can be met with a metallizing layer consisting of two-part silvering or tiny aluminum flakes. There is a lot of synergism between the base coat, metallizing layer, and UV-protected top coat -- so you usually buy the process of "chrome-look paint" from suppliers who offer the system. Good luck.

Regards,