Cutting dome

Discussion in '400-Day & Atmos' started by tracerjack, Sep 12, 2019.

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  1. tracerjack

    tracerjack Registered User
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    Jun 6, 2016
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    Has anyone tried cutting down a glass dome? The Koma midget I have came with a modern seven inch miniature size dome. So not a valuable dome. It is the right size in width, but wrong height. I can’t find glass or acrylic domes in four by six inch size. That’s what got me thinking about cutting down the one I have, but am hoping I can get some guidance before I attempt something I’ve never done before.
     
  2. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    I went through a period to try and find a dome for an older clock of mine...the dome sits in a groove in the base so I had to have a specific width...and it's an unusually tall clock. I finally got something at glassdomes.com but they did the cutting for me.

    Leading up to that, I thought I had something that might work...it wouldn't fit in the groove but would rest on top of the bass. I bought it at HobbyLobby. I took it to a place here in town, Thad Ziegler glass. They attempted to cut it but the glass was not very good and it cracked. No charge and I was out only $30. It was worth a shot.

    Consider HobbyLobby, Michaels, etsy as well. I attend estate sales when I see some clock that might be worth checking out...occasionally, I've seen generic domes at those places and I just buy them because they're $5.

    I think to cut something, you're going to need a good setup...I think the glass had to be held well with lots of lubrication. I imagine the spacing on the teeth and the speed of the saw are critical. If you had something that was throwaway, might be worth a try. Otherwise, I'm not so sure.

    Kurt
     
  3. MartinM

    MartinM Registered User

    Jun 24, 2011
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    I have only done a couple but they went okay.
    I made a jig with a carbide scribe that held the dome securely in a corner (three pieces of 2x4).
    Whatever you can do to scribe the glass in a single line without multiple starts and stops or parallel lines.
    to break the ring off, use a slip-knotted cotton string wrapped around the scribed line and soaked in flammable liquid like alcohol.
    Light the string (safely) and the temp differential should fracture the line cleanly
     
  4. tracerjack

    tracerjack Registered User
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    Jun 6, 2016
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    Thanks for the tips. Like I said, my good intentions often go awry, so I've learned to ask. The 4 x 7 domes are available at both Ronell and Timesavers, and fairly inexpensive, so even if I break this one, I could try again. The 7 inch dome on the little midget just doesn't look right. I was very surprised that I couldn't find an acrylic dome, anywhere. That would have been so much easier to cut down. At the moment, my little Koma Diana has been running all night- very happy about that, since I dangerously moved the verge on its arbor because the exit pin pallet couldn't quite clear the EW tooth, and there was no more adjustment in the bridge. I wasn't about to try and bend or move the pin. Thankfully, my cautious squeeze was just right. Don't know when I'll get the courage to try a cut on the dome, but when I do, I'll let you know how it went.
     
  5. sjaffe

    sjaffe Registered User

    Dec 25, 2012
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    Go to Amazon and enter "bottle cutter" in the search bar for some ideas on tools for this. Cutting bottles is quite common. I would think you could use the same tools/techniques for domes. Then go to YouTube and enter "bottle cutting" for videos showing how to do this.

    Stan
     
  6. Harry Hopkins

    Harry Hopkins Registered User
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    Nov 16, 2011
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    First, I should say that I have never tried this but I recently saw this video on a YouTube channel that I subscribe to... It is a variation of the method that Martin described. It failed in this case but watch the video to the end and you will see that he eventually had success. See it here.

    In the search for cheap domes I occasionally stop by my local Goodwill store. Sometimes they will have a quartz 400 day clock and selling it for next to nothing.. If it have a glass dome (or even a plastic one for the right price) I always buy it thinking that I will someday need the dome. Sometimes I am even able to repair the quartz movement.. I don't really need (or want) any quartz 400 day clocks but sometimes I just can't help myself to try to save it....
     
  7. tracerjack

    tracerjack Registered User
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    Jun 6, 2016
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    The jig looks like it would work well for scoring the dome. Now, if the thin glass of the dome would break as clean as the heavy bottle glass, I’ll be all set.
     
  8. tracerjack

    tracerjack Registered User
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    Jun 6, 2016
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    In the mean time, saw and won a cheap quartz midget at auction. Dome was not only 4x6, but glass. Fit my Diana perfectly. So, I guess I’ll keep the taller dome for some miniature missing it’s dome that I’m sure will eventually come my way.
     

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