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Thread: Reducing thickness of a mirror, can it be done

  1. #1
    Join Date
    Mar 2015
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    Cambridgeshire, England
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    Default Reducing thickness of a mirror, can it be done

    I need to make some replacement mirrors for some galvos, they need to be 0.8mm thick; I've had no luck buying 0.8mm thick 1st surface mirros, but I did get a number of mirrors from a polaroid camera and they measure a fraction over 1mm thick; is there any way, without access to specialist equipment, any way of thinning these down? I guess the first thing is to protect the silvered face, the 1st surface mirrors I've bought before come with a blue plastic protective film, something like that would do the job if it can be purchased.

  2. #2
    Join Date
    Mar 2016
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    You could try hand lapping it. You would just need a piece of glass about 8 by 8 and some grits.
    You'd take the piece of glass, place it on a flat surface and pour a small amount of grit in the center, then add a drop of soap and enough water to make it a slurry. Then place your mirror in the center and drag it in circles, rotating the mirror every couple of minutes. Depending on the finish you want you could just use 220 grit or if you wanted you could work up to full polish. If you want a more detailed explanation just let me know.

  3. #3
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    Cambridgeshire, England
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    Cheers for that, I'll buy some lapidary abrasives and give that a go.
    Still looking for suitable protective film before I give it a try.

  4. #4
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    Default

    I used to buy big BB dielectric mirrors from Newport, about 2in dia x 1/2in thick and have them sliced very thin (<1mm) with a diamond saw and then cut to size for scanner mirrors. You have to start out with a thick enough mirror substrate to hang on to. Easier to make a thick mirror thin than to make a thin mirror thinner.

  5. #5
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    Cheers Photon, I'll look into that to see if I can locate someone with the appropriate equipment

  6. #6
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    Mar 2016
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    Look into 3m buttercut or the cheaper alternatives. They'd probably work for protecting the surface. They're made for sandblasting glass but are ment to be easily removed and and leave no residue.
    Last edited by youngsquid; 04-11-2016 at 11:48.

  7. #7
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    May 2007
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    1 hr from everything in SoCal
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    Default

    Curious if First Contact would be up to the task.
    Those who fail to grasp art are the ones who criticize it.

  8. #8
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    Mar 2015
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    Cambridgeshire, England
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    I managed to locate an extra low-tack polyethylene tape that looks very similar to what my mirrors from Edmund were protected with; I've ordered a roll to try; it's a lot cheaper than the 3M buttercut!

  9. #9
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    Mar 2016
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    http://www.ebay.com/itm/Edco-Vinyl-R...25.m3641.l6368
    3m buttercut is really good for sandblasting but yeah it costs quite a bit. This is a thinner version that's pretty much the same thing but is only 4.99 for a 12x12 square. I'm not sure how cheap the polyethylene tape is but this might be worth looking at.

  10. #10
    Join Date
    Jun 2007
    Location
    Monroe, Mi USA
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    818

    Default Long ago....

    Long, long ago....I had Glass Blowing as a hobby ( for a short while !! ). When I finished a new piece of glass "art" ( after full annealing).....we would " Sand " the bottom to a flat smooth surface. A 3 cm x 40 cm steel platen was driven by a pulley/motor combination....likely 80 ~ 100 RPM. Water was continuously delivered to the platen top within a closed loop system. The piece would be positioned atop the rotating platen.....with minimal downward pressure. Slowly...slowly the bottom would become a flat plane. IIRC....some ultra fine diamond grit was used to cut/ablate the glass.

    I abandoned this artistic sortie....as Glass Blowing was just too challenging....and....many of...my eeer...." Works de art "....well.....looked " like they went thru a malfunction Star Trek Transporter.....and I even had one treasure ....looked like....a " Road Apple under glass "....no kidding....Just a large glass sphere....with a Cow Pie inside !!! hahaha... Time to choose a new hobby !!!

    Anyway......Perhaps seek out some local Glass Artesian or University that offers some facilities in this area ???

    I do find it hard to believe that such a thin mirror material is not available.....somewhere ??? Maybe at prohibitive quantity buy restrictions ??

    Anyway....glass can be ground....not that big a deal....a little movement, water and diamond dust...and Whaa Laaa
    Beam Out
    Last edited by CDBEAM; 04-14-2016 at 19:16.
    Beam Axiom #1 ~The Quantum well is DEEP ! Photons for ALL !!
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    Beam Axiom #2 ~Yes...As a matter of fact...I DO wear tinfoil on my head !!
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    Beam Axiom #3 ~Whe'n dout...Po ah Donk awn et !!
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    Beam Axiom #4 ~A Chicken in every Pot, and a Laser Lumia in every Livingroom !!
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    Beam Axiom #5 ~"Abstract Photonic Expressionism"....is "Abstractonimical" !!
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    Beam Axiom #6 ~ "A Posse ad Essea" ~ From being possible to being actual ...is the beam target !

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