Cutting 1/2in Glass?

If it is from an outdoor table it maybe tempered glass, you can’t cut that.

-- Tom D

Score it just like cutting any glass except It’s much harder to snap and lots more dangerous. Just a tap is not going to do it. I WOULD NOT recommend doing it yourself. I’ve cut a lot of glass, and even some 1/2”, but it doesn’t always go smooth. Sometimes the break won’t follow the score line and some times the glass will break where your holding it. VERY, VERY dangerous for us inexperienced. As much glass as I have cut, I myself would still take it to a glass shop to have it done.
As Tom said, If it’s Tempered it can’t be cut by anyone.

Hmmm interesting. Is there anyway to distinguish whether or not its tempered. Cause if its not I’m just gonna wing it… and go all out on safety gear haha.

Smack it pretty good on the edge with a crescent wrench. If it’s tempered it will explode. I suggest safety glass and gloves and prepare for a good mess. If it doesn’t shatter the first time I would smack it 2 or 3 more times a little harder each time. If it chips or clams it’s probably plate glass and not tempered.

If your going to try and cut it yourself. You need a good cutter, you should oil the wheel. After you score it you should snap it right away while the cut is still hot. The few times I have tried (and remember take this for what it’s worth I’m not an experienced glass cutter) I lay the glass on a flat table on top of a pc of carpet or a moving blanket, putting the score line at the edge of the table. Then I lift the front of the glass that is hanging over the edge of the table and flop it down hard applying pressure all the way down like your trying to bend the glass in half sort to speak.

I still recommend a glass shop. Please be careful if your going to try this. Also wear goggles and a good pair of gloves in case it breaks where your holding it. You never know what can happen. (1/2” thick is hard to cut.)

You might also want to see if you can find any instructional videos on youtube before you try.

A quick check with google shows there are other ways to check for tempered glass other than smashing it. While the sites I looked at all said you can examine the shattered remains, it was always last on the list. Seems a little odd to recommend smashing it when there are a couple of other ways to figure it out. So here you go:

1. Check the corners of the piece of glass. If the glass is tempered, it is required for the manufacturer to etch the four corners, identifying it as tempered or safety glass.

2. Look for dimpling and imperfections, which were caused during the heating process. Tongs used to remove tempered glass from heat often leave small impressions in the glass that can identified if you look closely.

3. View glass at an angle through polarized sunglasses. Polarized sunglasses expose black lines in the glass that occurred during the heating process. These lines become more prominent at sharper angles.

4. Hold the glass out straight and look for signs of warping or bending. Sometimes the heating process causes mild warping that is easy to identify.

5. Analyze the shattered remains. Safety glass is designed to shatter completely, leaving behind no large shards on which a person might harm themselves.

Good Luck

-- Mike

#1 They don’t always Mark the glass. It’s not a requirement, I order tempered glass all the time without the button stamp all the time. I build glass display cases that go into stores and they can’t have the marks on them. Not Definite #2 A Good tempered glass company doesn’t leave tong marks, A glass shop I used to work at used to hang the glass to temper it and it would leave tong marks, but that’s old fashion tech. I doubt you will see any. Not definite #3 Possible, I’ve never heard it before. #4 Sometimes you can spot warping but not always, you would have to be experienced to tell. Not definite #5 Smash it! LOL The most definite way to tell. Will give you a positive conclusion.

Did google say what would happen if you try to cut tempered? When you try to snap the glass is it going to blow up in your hands and face?

I’ve tried to cut a 1/4” mirror before. I got scared. No way I’d try to cut 1/2” myself.

Alternatively, why not just get a small plate of granite…it’s cheap (and sometimes free). Granite tiles works well for this.

-- jay, www.allaboutastro.com

Ive heard of people going to a granite shop and asking for scraps for either free or for a few bills. Is this true?

Mark, although I haven’t done that, I heard of some other people who had success with picking up scraps at those places. I’ve also seen off cuts at the big box stores that sell for pennies on the dollar as well.

-- Mike

Mark, that’s exactly what I did. I walked into a countertop fabrication shop and asked what they would charge me for a cut-off piece. The guy just laughed, pointed at a stack of scrap on a pallet and said to take as much as I wanted, ‘cuz they were just going to dump in a pit as fill. I found a decent piece a couple layers down, took it out and re-stacked the rest very nicely. I think the key was going in offering to pay for it instead of asking for something for free.

A tip I picked up at the Woodworking Show was to try and get the granite after it has been cut and machined flat, but before polishing. Since polishing is done by hand, it actually induces small imperfections and waves that were not there when the machines finished. Probably not enough to really make a difference, but if it is avoidable, why take the chance.

Another option is finding an installer and seeing if you can get a cut-out from a kitchen sink.

-- "The U.S. Constitution doesn't guarantee happiness, only the pursuit of it. You have to catch up with it yourself." -- Benjamin Franklin