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Thread: Cutting your own mirrors

  1. #1
    Join Date
    Jan 2007
    Location
    Florida
    Posts
    4,382

    Default Cutting your own mirrors

    I 'll try to post pics later,
    but I thought that this might be of some help for you DIY'ers..

    So, you've got a 1.5" x 1" fs mirror and you want to mount it to an itty-bitty something mirrormount or galvo etc... What I'm doing thesedays is..(and this may be dangerous -c.y.a. disclaimer)(and some [not all]of the info came from different sources)--but-- here it is--
    • get a dremel tool with a cutoff disk
    • draw a line with a sharpie pen (using a straight-edge) on the back side of the fs mirror (dont remove the protective plastic film)
    • Get ready to hold your breath for a long time--
    • put on safety glasses
    • Hold breath
    • cut along the line with dremel on high speed(the tip of the cutting wheel will turn orange-red) until a significant cut is apparent
    • pour alcohol on the cut (not yours-'cause hopefully you didnt get one) on the mirror back- wetting helps weaken the stress-cut point of the glass-
    • carefully apply enough pressure to break the mirror at the cut-point
    • Immediately go from the room and breathe
    • make sure room is ventilated B4 going back in
    • X-acto knife the protective film to separate.
    • happy mirroring..
    • I just got through doing 1 tonite..
    • anyone please feel free to contribute any glass/ mirror-cutting experience to this thread

  2. #2
    Join Date
    Sep 2007
    Location
    Texas
    Posts
    740

    Default Cutting glass

    TOYO carbide tipped glass cutter & cutting oil - safe, easy ($20.00 - $30.00).

    Greg

  3. #3
    Join Date
    Jul 2005
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    Flying over a town near you
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    1,404

    Default

    I have offered times before to cut glass or crystals to your desired size for shipping costs and small fee for supplies. I have 2 faceting machines and several laps from 100 grit down to 150000 diamond abrasives. Also have 2 diamond cutting saws. PM for any job you have....I also do carbon fiber proto's. All cutting/grinding is done with water cooling to control heat. I have cut a 8mm x 20mm x 1.5mm mirror into 4 pieces. I have vacuum work holders for the tiny stuff.
    You are the only one that can make your dreams come true....and the only one that can stop them...A.M. Dietrich

  4. #4
    Join Date
    Jan 2007
    Location
    Florida
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    Default

    i also just thought of the glass cutting tool sold by most HW stores but s/h charges -- and having to packing it up -- not knowing what size you'll need at the next moment -- but i may take U up on that --/cause it sounds alot less caustic...

  5. #5
    Join Date
    Jan 2007
    Location
    Florida
    Posts
    4,382

    Default

    Speaking of glass-- does anybody know of how to semi-circulize a 7 degree by 40 degree LD using anamophoric prisms-- cut to I guess would be negative -0- -7 x -0- -40?

  6. #6

    Default

    We use a higher quality stained glass, glass cutter with replaceable tips. We start by oiling up the tip and then score the glass. Then we use a glass breaker with rubberized ends to snap the glass. It works almost 98% of the time and we cut mirror from anywhere between .5mm to 5mm thick with the same setup. We noticed in the past that the rotary bits tend to flake the front surface coating on the mirror. If the glass seems to be extremely touchy we then use a diamond scribe to score the glass but again its still all by hand. Also we cut these pieces as small as 1/4" by 1/4" and still use the breaker to snap them without fail.

    "Edit" BTW it is a TOYO glass cutter. Exactly what Displaser said... We have been using this method for over 10 years.

    Last edited by OSLS; 10-08-2007 at 19:09.

  7. #7
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,488,218

    Cool

    I've done the dremel-tool trick like Steve-O mentioned, and while it does work, OSLS is correct - you can booger-up the face of the mirror doing this. Best to work from the back side, or else cut the mirror large enough that a little damage near the edges won't hurt you.

    I wouldn't try to cut a really tiny mirror this way, but if you've got a large one that you want to cut down it works quite well. (Actually, I didn't even think about the holding-my-breath part... Wonder how much glass I might have inhaled?)

    One thing - I don't let the glass or the cutting wheel get red-orange hot. If you do that, the glass will likely crack. Fortunately, it will probably run along the score mark you've started, but I like to gently cut a score mark nearly all the way across the glass first (going very slow so the wheel doesn't get hot and neither does the glass). Then, once you've got a mark that runs most of the way, you can cut deeper and faster, because if it overheats and cracks, the crack will follow the mark you made.

    I've done it this way about a half-dozen times on really thick mirrors (1/4 inch and up), and many times on thinner mirrors. (The thin ones need more care; they can't take the heat as well.)

    Adam

  8. #8

    Default

    Thread saw? I'm thinking that if you took the drive pulleys from a cheap cassette recorder, and the motor, you could form a loop drive, where a thread was drawn across the glass to be cut, and part of the loop could be continuously dampened before it is drawn through some means of applying a small amount of abrasive, maybe diamond powder. This could form an extremely clean, controlled cut. It might not be very fast, but it could be made to cut one piece per half hour or so, and most of the time you could be doing something else.

    Main sticking point seems to be the diamond powder. I looked on eBay, but that's something I don't think anyone sells through eBay.

    I'm not sure what thread is best suited, but a dacron braid fishing line might do, or the stuff used for mechanical radio tuning indicators. The main problem is the knot, it is best joined without one, or fitted to a rig that reverses the motor so the knot never passes over the cut. With a decent length, and gentle tension, the thread will outlive several cuts in glass.

    Another idea is a water knife. Not sure how practical that would be though. Probably not cheap either.

  9. #9
    Join Date
    Dec 2006
    Location
    denver,co
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    1,078

    Default

    Hi, I posted a while back with my mirror cutting exp.

    Take a look at the end of the post.

    http://photonlexicon.com/forums/showthread.php?t=2708

    chad


    When the going gets weird, the weird turn pro.


  10. #10

    Default

    Really this is an art... Especially the smaller you get and even more so when the cost of the glass increases dramatically. Be it front surface aluminized mirror, or broadband dielectric to even very high efficiency dichroics that when you put the mere weight/force of the cutter on them they tend to shatter.

    I will try to compose a reply that will lay it all out so everyone can learn from our past experiences. Really I have had the pleasure of shattering many $1000.00+ pieces of glass over the last 15 years and when you you finally get the hang of it then it becomes a very simple process to master.

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