|
Straight aluminium around 2-5 years, depending upon storage conditions.
Aluminium + quartz around 10 years again dependant upon storage.
Aluminium + quartz + overcoat 15 years plus, again storage dependant
I just had a small 5" mirror come in which is aluminised and quartz overcoated, because it has been stored in a bedroom, not dried properly before storage, the dew has eaten in under the edge of the coating and the couple of pin holes that were through the overcoating have allowed oxidization of the aluminium.
|