Thin Metal Films

Large Front Surface Mirrors

Construction

All Mirrors are manufactured from selected float glass, thickness dependent on customer application. A thin layer of pure aluminium is evaporated under very high vacuum onto the surface of the glass and the film finally overcoated with a layer of metal oxide or fluoride material. The overcoat is transparent and acts to improve abrasion resistance and minimise atmospheric attack.

Glass

The material used is commercially available float glass, which is selected for quality by TMF. In particular, selection is to ensure that the coating surface is free from scratch, stain, seeds and ripple.

Flatness of the glass is not guaranteed by the manufacturer but is generally expected to be in the order of 12 fringes per 25mm for standard production. A special 10mm thick float glass is available but is restricted to a maximum dimension of 750 x 1000mm. The flatness is in the order of 4 fringes per 25mm.

The mirrors can be manufactured in a range of glass thickness, normally 2, 3, 4, 6 and 10mm, with a maximum size of 1800 x 3000mm for 6mm only. All mirrors manufactured from stock glass have a cutting tolerance of +/-2mm and a thickness tolerance of +/-0.2mm.

Coating

TMF aluminium front surface mirrors are designed to meet the general requirements of the U.S. Military Specification MIL.M.13508B particularly in respect of abrasion resistance and film adhesion. This allows for satisfactory cleaning of the aluminium surface providing the approved method is used - Data Sheet on cleaning recommendations 688 - 11. It is strongly recommended that any finger prints deposited on the mirror surface during installation be removed as soon as possible as finger grease will etch into the coating with time.

Packaging

All large mirrors are wrapped in acid free tissue and corrugated paper as standard.

Customers with their own suitable transportation and experienced handlers can safely collect the mirror in this packaging. Where mirrors are to be transported by carrier services, then the mirrors must be placed in wooden crates for handling and protection.

Please call or email us to discuss any variations in standard coatings that you may require.

Download Specification in PDF format