how to cut thick glass


SGF, Supreme Grumble Framer
Mar 25, 2004
Tampa, FL
hi all...
the biz next door just brought in a broken glass countertop---a little over 3/8" thick--to be cut down/reused elsewhere & I have no idea how to cut this thick stuff......anyone out there donethis???? what do I need to do(other than take it to a glass place)?

I love it when people bring in storm windows to be repaired because we work with glass.

Do you owe these people a huge favor? Are you going to be held responsible if you screw it up? Are you going to seam the edges?

It IS basically like cutting picture glass but with a higher probability of messing up.

take it to a glass place
That would be my suggestion to them.
Yep, score and snap. Give them the the disclaimer.

It was trash already. Sounds like they're just trying to salvage what is left.

LOL! People bring storm windows into the frame shop? Sell them museum glass and standard fitting fees

You already know the answer.
Refer them to a glass place.
Score the glass, place the glass on a flat surface and slide a wooden dowel under the score. Make sure to protect your eyes and just push down on one or both sides of the glass opposite the score. Now you have a raw cut piece of thick glass, your gonna need a seamer to clean up the edges. Be sure to tell the owners of the glass that there is a very good chance it will not work and you ain't gonna be responsible.

I just won't do it. I refer them to the glass place. I don't have a proper seamer and I tell them it's about safety for them, I would never let them leave with a large piece of glass that could hurt them. I could get a seamer, but I just can't want to. That thick stuff makes me nervous. It's finicky.
triedto do it on the wall cutter---its so thick & hard(is counter glass tempered???) it just popped a very ragged edge where I was using the grippers...will try the dowel trick next & yes, its just a piece of scrap/junk glass that would be used IF it could be cut clean...seamer is NO problem guys...just get a good stone(can even be a very small one!)

thanks all
This piece is not tempered because it is already broken and did not break into a bunch of tiny cubes.

You should be alright as long as you keep the score a few inches from the parallel edge.
Make sure you leave a few inches of waste. Glass cutters have different angles on the wheels for different thicknesses. Use the appropriate angle cutter (any glass supply company will have them)and dab a piece of fabric in Kerosene. Now wipe the proposed cut line with the rag before scoring. The wider the waste, the easier the snap.

Best way to finish the edge is with a handheld belt sander with an emery cloth belt. Takes a couple of minutes versus hours with a seamer.
Jeff just hit the nail on the head... different thicknesses of glass require different angles on the cutting wheel. Getting the right one for the glass will solve the problem.

Be very careful when trying to cut aged glass, esp the ones exposed to the elements for quite some time. In my very limited experience, old glass is less brittle and considerably tougher to score...If you had never tried your hand on this type of glass (and thickness) wary, let the glass window fitters do it.