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Re: Alumnized Mirror Failure

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Posted by Gerry Brummund on September 7, 1999 14:26:08 UTC

Two small edge chips were expoyied back during grinding. The glass is BVC which is has layers. The chips are on the edge but do not lay on the optical surface, as they were chipped at the far edge and back under the edge to the next layer. The chips were expoyied about 6 months ago during grinding (first mirror) and the hase on the mirror is focoused on the centre of the mirror and not the chips, althogh the outgass of the expoy might settle down on the mirror?

Thanks

: : two chips were expoyied back?????

: Am I to understand that you put epoxy on the glass to put some small chips bac onto the mirror? Yes, the epoxy will outgas and cause problems. The coater should have asked you about the problem if it was visible. It's better not to epoxy anything onto the mirror before it's getting coated. If the chips you are talking about just little 1/4" or smaller chips off of the edge then they shouldn't have been epoxied on as thier distortion of the image is insignificant to the mirror. You should let the coater know of any strangeness that you may have done to the mirror beforehand like an epoxy job. Bet that the haze is next to the epoxied areas. Send the mirror back to the coater and let him know what you did and to please fix it. : If the chips are large, you might as well call the mirror a poor mirror and just live with it. : I don't know what else to tell you but the coating job is bad and it may have been the epoxy, especially if the epoxied area is where the haze and other problems are.

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