norcutt@xxxxxxxxxxxxx writes:
<< Silver is a bit more reflective but I don't think it would be used
anymore due to poor durability relative to aluminum. >>
Regular domestic mirrors today are still real silver and they are
produced, as they have been for many years, using electroless deposition. The
magic mixture of chemicals used has more than just the basic silvering
solutions given in a traditional chemistry lab book. My father-in-law
produces mirrors (in a third world country, OSHA would be horrified!) The
basic process involves mixing two premixed solutions together as it is
applied to the glass from a mixing spray gun. The solutions contain not only
a silver compound (silver nitrate) but small quantities of things like copper
and a reducing agent (I seem to remember dextrose) .Something like about 8
chemicals in all. To make the silver adhere better and cause the silver to
come out of solution quickly, the glass is preped by painting on a tin
compound. Traditionally and probably on older cameras the silver is protected
from oxidation with a lead based paint. For environmental reasons and better
performance modern mirrors are copper plated and then painted with a less
toxic paint.
I talked to my father-in-law about resilvering a pentaprism some years
back and it seemed like it would be easy to do with his set-up but would
require very careful masking to keep the silver off unwanted areas as well as
maybe a smaller sprayhead. In addition the old silver would probably have to
be stripped off to make a perfect job with no blemishes.
Regards,
>>Tim Hughes<<
>>Hi100@xxxxxxx <<
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