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Old 26-02-2015, 04:12 PM
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CJ (Chris)
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Doh! Damaged my primary.

I just removed the primary mirror from my XT10" to clean it, as I knew it had some finger marks on it. Unfortunately, while undoing the surprisingly long screws on mirror clamps, my screwdriver jumped out of a screw head and landed point first on my mirror! It has left a very small spot of damage, presumably at least breaking the coating. Assuming the coating is protective, will this cause the surrounding area to deteriorate, like a chip in the paint/galvanising on car body work?
What should I do about it?
Thanks in advance.
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Old 26-02-2015, 04:29 PM
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multiweb (Marc)
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The area of the chip is so small that is very unlikely to degrade the images given by the scope. If you're worried about water getting under the coating, short of recoating the whole mirror, I'd put a drop of black flat paint on the tiny hole to seal it.
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Old 26-02-2015, 06:53 PM
kens (Ken)
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...very carefully
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Old 26-02-2015, 07:11 PM
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I know it won't make you feel any better now, but the mirror clip screws should be screwed in and out without a screwdriver. It prevents accidents like yours and besides, the mirror clips shouldn't touch the mirror and therefore the screws only need to be screwed down less than finger tight.
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Old 26-02-2015, 07:12 PM
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mental4astro (Alexander)
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Quote:
Originally Posted by multiweb View Post
The area of the chip is so small that is very unlikely to degrade the images given by the scope. If you're worried about water getting under the coating, short of recoating the whole mirror, I'd put a drop of black flat paint on the tiny hole to seal it.
Yup. Just what I was thinking too. And as Ken says "very carefully"...

This will do two things, re-seals the coating, and stops any interference of unwanted reflections from the shattered surfaces becoming a nuisance with bright objects.
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Old 27-02-2015, 10:34 AM
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CJ (Chris)
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Thanks for the advice.
It was the long term effect of moisture that I was worried about.

I was being very careful but I took my mind off the job for a moment and fumbled it.

Thanks
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Old 27-02-2015, 10:46 PM
el_draco (Rom)
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Heard a story about how a disgruntled employee unloaded a full clip into a 72 inch mirror once... bugger all effect on image quality....
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Old 01-03-2015, 10:39 PM
frank farrell
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I have access to mirror clips from outside rear of mirror cell. Clips, once loosened, slide away from mirror. Easy access and no naughty screw drivers.
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Old 01-03-2015, 10:51 PM
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CJ (Chris)
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Originally Posted by el_draco View Post
Heard a story about how a disgruntled employee unloaded a full clip into a 72 inch mirror once... bugger all effect on image quality....
Was he fired?
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Old 01-03-2015, 11:09 PM
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CJ (Chris)
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Quote:
Originally Posted by frank farrell View Post
I have access to mirror clips from outside rear of mirror cell. Clips, once loosened, slide away from mirror. Easy access and no naughty screw drivers.
Sounds like a good arrangement. Any chance of a photo? (thousand words and all that) My bolts must have about 15mm of slack that needed taking up. If I hadn't had to spend so long turning them I might not have lost concentration. I could fit shorter ones but its a bit late now.
Cheers
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