Metallizing

Metallizing is a technique of coating metal on the surface of non-metallic objects. Because a non- metallic object tends to be a poor electrical conductor, the object's surface must be made conductive before plating can be performed. Vacuum metallizing is one method of metallizing which involves heating the coating metal to its boiling point in a vacuum chamber, then letting condensation deposit the metal on the substrate's surface. Vacumm metallizing was used to deposit aluminum on the large glass mirrors of reflecting telescopes.