At 1:57 AM +0000 4/20/98, Tony Moss wrote: >Fellow Shadow Watchers, > >A slightly off-topic request but I know there are many list members with >an astronomical interest. > >Many years ago I silvered my home made telescope mirror using a recipe >containing silver nitrate and sugar I seem to remember. It was called >'Brayshear's Process' or something similar? They use more durable >aluminium for this purpose these days so it isn't mentioned in anything >printed more recently.
SNIP>>> Tony: The closest I can come up with for a silvering recipe is that used by us in the antique clock restoration business, but that is for use on brass. I've never heard of the use of sugar. Could you be thinking of salt? To silver brass, as in clock dial chapter rings (or astrolabes, etc.), the silver nitrate is converted to silver chloride by combining it with salt and cream of tartar to make a paste which is applied to the brass by rubbing, following preparation of the surface by rubbing it with salt. If you or anyone else wants the formula I'll be happy to provide it. Early "looking glass" mirrors used, I think, mercury which might also work for you. In order to increase the contrast of old sundials preparatory to photographing them they can be silvered temporarily, then cleaned off to their original state following the photography session. (That keeps me on-topic!) Ray Ray Bates, MBHI, Pres. The British Clockmaker, Inc. P.O. Box 102, West Street Newfane, VT 05345 USA http://www.thebritishclockmaker.com
