Glass and Mirrors - Cutting front-surface mirror
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Crona
08-14-08, 05:36 PM
This isn't exactly a home-decor question, but it does involve mirrors & I'm hoping somebody with lots of experience cutting glass will have the answer.
For a science project, I am working with front-surface mirror, the type used in cameras & other optical devices. This mirror has the aluminized surface on the front, not the back, like household mirrors. It must be cut with a carbide wheel because it's very hard.
I've never cut glass before, so I looked up glass-cutting technique on the net, got a piece of scrap glass from the hardware store, bought a carbide cutter, had one of the guys at the store show me his technique, practiced at home & thought I had it.
But I never got a single good cut when I actually worked on the mirror. I'd see a clean score, but the pieces wouldn't break. I'd have to turn it over and tap the back. Even then, not much luck. Out of 8 cuts (10 pieces), I got only 1 perfect piece and 2 usable, though flawed, ones. The rest just shattered. :wall:
Since this material costs $7 for a 7 x 6-inch piece, I can't afford to mess up so much. HELP! Anybody know how I can get better results?
For a science project, I am working with front-surface mirror, the type used in cameras & other optical devices. This mirror has the aluminized surface on the front, not the back, like household mirrors. It must be cut with a carbide wheel because it's very hard.
I've never cut glass before, so I looked up glass-cutting technique on the net, got a piece of scrap glass from the hardware store, bought a carbide cutter, had one of the guys at the store show me his technique, practiced at home & thought I had it.
But I never got a single good cut when I actually worked on the mirror. I'd see a clean score, but the pieces wouldn't break. I'd have to turn it over and tap the back. Even then, not much luck. Out of 8 cuts (10 pieces), I got only 1 perfect piece and 2 usable, though flawed, ones. The rest just shattered. :wall:
Since this material costs $7 for a 7 x 6-inch piece, I can't afford to mess up so much. HELP! Anybody know how I can get better results?
hrjrkr
08-15-08, 04:01 AM
The best thing to do is get a good glass cutter not the cheap ones they sell at the hardware store. http://www.scstainedglass.com/fldeiiglcu.html
Next make sure you are cutting on the glass side without the mirror film. Also, if the glass has been heat-treated it will be impossible to cut it.
If you have some kerosene,(other lubricants work but kerosene is the best)use a small brush and wet the area that you are going to cut. When you cut don't use too much pressure as this will make it harder to break the glass at the cut.You should only use enough pressure so you can hear the glass being scored. With a good cutter and lubrication, it doesn't take much pressure at all and you will get a clean cut.
Good luck
Next make sure you are cutting on the glass side without the mirror film. Also, if the glass has been heat-treated it will be impossible to cut it.
If you have some kerosene,(other lubricants work but kerosene is the best)use a small brush and wet the area that you are going to cut. When you cut don't use too much pressure as this will make it harder to break the glass at the cut.You should only use enough pressure so you can hear the glass being scored. With a good cutter and lubrication, it doesn't take much pressure at all and you will get a clean cut.
Good luck
Crona
08-15-08, 12:19 PM
Thank you, hrjrkr!
I'm using a carbide cutter that has has its own built-in lubricating well (which I filled with 3-in-1 oil). But I DIDN"T know about cutting on the non-mirrored side. I mistakenly thought that to get a clean cut I HAD to work on the mirrored side!
I've been working more on this problem since I first posted. You're absolutely right that correct pressure is the key. I'm listening for a "zip" sound as I practice more and almost trying to get into a Zen cutting state, if that makes any sense.
I discovered I was also not snapping the scored glass properly. I wasn't gripping it near enough to the score and wasn't putting enough pressure on the "snap."
The resident glass expert at the hardware store taught me a neat trick, too, when I went back to him a second time. He showed me how to scrore the glass, then slip the point of a pencil under the beginning of the score. Press down lightly on either side of the pencil-point and -- NICE CLEAN BREAK.
Between you and him, I think I've got it now. Thanks very much for the help!
I'm using a carbide cutter that has has its own built-in lubricating well (which I filled with 3-in-1 oil). But I DIDN"T know about cutting on the non-mirrored side. I mistakenly thought that to get a clean cut I HAD to work on the mirrored side!
I've been working more on this problem since I first posted. You're absolutely right that correct pressure is the key. I'm listening for a "zip" sound as I practice more and almost trying to get into a Zen cutting state, if that makes any sense.
I discovered I was also not snapping the scored glass properly. I wasn't gripping it near enough to the score and wasn't putting enough pressure on the "snap."
The resident glass expert at the hardware store taught me a neat trick, too, when I went back to him a second time. He showed me how to scrore the glass, then slip the point of a pencil under the beginning of the score. Press down lightly on either side of the pencil-point and -- NICE CLEAN BREAK.
Between you and him, I think I've got it now. Thanks very much for the help!