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Durability of silver as a mirror coating.
Hi mirror makers,
Over the years there has been a lot of discussion regarding the durability of silver when used to coat first surface mirrors (as in telescope mirrors). Thought to share my own experience. Its just on a year since I "spray silvered" a pair of larger mirrors, (22" and 25"). I might add this was my first attempt at home silvering. The cost of materials used for the two mirrors was around $40.
Contrary to popular belief a raw silvered surface is actually quite resilient to all sorts of abuse. At around 6 months into its life I had to do a clean (after a 150km house shift [25" OTA was transported in vertical orientation in open trailer alone some roading that was loose metal/gravel]). To put it mildly the mirror looked a mess. To clean or not to clean? Well not to clean was not an option, so mirror out and with the garden hose most of the crud was removed. A little help with lightly warm water, suds, and clean piece of cloth the remaining dirt was persuaded to leave. Finally a spray down with de-ionized water.
Pictures one and two show the washing down and cleaned mirror returned to the scope. Picture three: the mirror surface at 11 months.
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