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Re: [Phys-l] mirrors




On 2011, May 03, , at 07:11, Anthony Lapinski wrote:


Also, what substance is used on glass mirrors -- aluminum or silver? I
figured aluminum since it is cheaper, but my chemistry colleague suggested
silver (which could be removed from glass mirrors with concentrated nitric
acid).


I suspect a chemical bath is less expensive than a very large vacuum chamber.

I used the Brashear process where sugar is used to reduce silver nitrate. Though I had an evaporator for telescope mirrors, I thought easier to silver a cylinder. On old mirrors it's obvious, as the deterioration around the edges appears like old sterling patina.



Chem. class instructions:


http://docs.google.com/viewer?a=v&q=cache:pAa7cBI7sRYJ:cache.micron.com/%24assets%24/beb62e98-5e25-47bf-b765-6804a3086726/deposition.pdf+silver+%22brashear+process%22&hl=en&gl=us&pid=bl&srcid=ADGEESh6ecwxDaiZ_U3r3UR_w2vxTUD7HFsGz1huqKW8BrUaTGe57GJCM0lrfHDl0yPM61id4lTGrTWycURIc437M1Ql2KUMUn7EB2H-abmP3uPdMMiTOuvgQFnaLifguGCkdxRDij2I&sig=AHIEtbS2g8Ddk0xnp3V62iaMdyPfsEPjYg


From Harvard Advanced labs.:


http://articles.adsabs.harvard.edu/full/gif/1895ApJ.....1..252W/0000253.000.html


bc used instructions from a contemporary Chem. Rubber Co. HdBh. (ca. 1955)