Curve cut on door glass ???

[newood2]

How do I do a curve cut in 1/8" glass to fit the top part(cathedral profile) of this door shown below. The glass size is 8" X 30".
I never cut glass before. What kind of tools do I need?


My other option was to route the "X" section and cut the glass straight, but that would leave too much wood with only 3/8" thickness, which could warp and split.


How about a glass store doing the job, would that be better?
Howie

[Popeye]

I'd let the glass store do it. Pat

[atgcpaul]

I've done this with one of those handheld glass cutting pens on a clock
door that had a 6" diameter arch top. I gave it a good score, tapped it from
underneath and it snapped with no problem. Yours is almost a straight cut
so it shouldn't be that hard.

[Daryl]

Get a tool like Paul's and dip it in a real thin oil before starting each cut. 3 in 1 will do. Do not retrace your cut, just one firm go at it. Practice on a piece of scrap if possible.

[cabinetman]

One eighth inch glass is easy to cut. Make a template with paper for the curve, and from that make a smooth edged template out of most any substrate.

Keep in mind the cutting wheel distance from the frame of the cutter when making the template. When drawing the cutter across the glass always pull towards you, don't push away. Start at the edge away from you, set the wheel on the edge, apply slight pressure and make one pass. Hold the cutter straight as you pull. It should be about 60 deg to the glass. Make sure the glass is absolutely clean with no debris, and using a light oil, and a brush, swipe a path where your cut will be.

After your pass, you may have to tap at the end of the cut (closest to you), with the ball end of the cutter on the underside of the glass. With both hands, give the two halves a quick short snap.

You can smooth the cut edges with silicon carbide sandpaper (wet-or-dry) wet, and 120x works good.
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[newood2]

Thanks very much guys for the detailed instructions. Now I'm encouraged to go get me a piece of glass , cutting pen and oil to practice on. You sure make it seem like something I could very well do. I'll keep you posted.
Howie

[charliex]

When you make a test cut watch the cut line closely, if there is any skip (where the glass don't score ) it could be a bad cutter, don't try it on a curve. It may well work on a straight cut but would be disaster on a curve. When you store it protect the score wheel well. If you ever drop it, toss it.

After scoring start tapping from the top of the curve, that way if it runs on you it will run into the waste portion and not into the part you want. I would avoid the quick snap as suggested and go for light taps from the back along the cut line. If you watch closely you will see where it is breaking. Stay behind the break. If you get ahead of it there is a good (bad) chance it will run where you don't want it to go. I spent 3yr. 7 mo. cutting glass.
Chas

[cabinetman]

When you make a test cut watch the cut line closely, if there is any skip (where the glass don't score ) it could be a bad cutter, don't try it on a curve. It may well work on a straight cut but would be disaster on a curve. When you store it protect the score wheel well. If you ever drop it, toss it.

After scoring start tapping from the top of the curve, that way if it runs on you it will run into the waste portion and not into the part you want. I would avoid the quick snap as suggested and go for light taps from the back along the cut line. If you watch closely you will see where it is breaking. Stay behind the break. If you get ahead of it there is a good (bad) chance it will run where you don't want it to go. I spent 3yr. 7 mo. cutting glass.
Chas

I disagree with this part (bold type). Tapping for a crack in the middle of a curve will cause separation stress in both directions. The likelihood of a stray crack is more possible.

Here's what I do. The score line is one single pass. After the line has been drawn (toward you), the wheel has exited off the glass cleanly. It's not like the top of the cut (start) where the wheel is positioned (actually I rock it on the edge to get a start), and the wheel gets a start, but is not as clean as drawn off the glass. Coming off the glass after the run gives a clean line. Tapping under the line at the end of the cut will start the run and you only want it to run in one direction (away from you).

As for the quick snap, glass will separate cleaner than with gradual pressure. Or, once the tapping starts (at the end of the cut), it may start a separation and go all the way. That is where you want to tap behind the separation and keep the run going all the way. Slight pressure lifting upward at the beginning of the separation will allow the two pieces to cleanly clear away from each other as they separate. It's way more difficult to type an explanation than to show in real time.

Cutting glass has a "feel" for the handling and pressures used. I prefer an oil filled/fed cutter like this:

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[JimD]

I used the "other method" - the big rabbet with square glass for some arched top doors I made.

Jim

[bigangelman]

No one mentioned that you should have the glass tempered when you are done cutting it. Since it is in a door it should be safety / tempered glass.

Tom

[cabinetman]

No one mentioned that you should have the glass tempered when you are done cutting it. Since it is in a door it should be safety / tempered glass.

Tom

Tempered glass does offer a degree of safety in that it doesn't break in large jagged pieces. But, it can what I'll call explode. What it does is to fragment either all of a sudden, or break in tiny pieces and continue to fragment for a period of time, and has the possibility of ejecting fragments for some distance. The tempering process is usually part of the cutting process as there is a shrinkage factor after annealing. The facilities that do tempering, do the figuring from given sizes and thickness to determine the cut size. So, if you want to have your cut piece tempered, it may come back a different size.

As for cabinet door glass, I don't use 1/8" for anything, even though it is light. I'll use 3/16" as a minimum and usually 1/4", which is pretty stout for cabinet door glass. If there is a high safety factor, I'll use cast acrylic sheet (like Plexiglas), or polycarbonate, which in 1/8" works very well. There are coated/treated acrylics used in certain industries like aircraft and boat windshields, designed to stand up to windshield wipers.
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