Glass cutting advise.

Hey folks. I am preparing to cut four pieces of glass for a display case I am building. the tops of the pieces will have a slight arc ( 1" over a 10" run) . I have never cut an arc in glass before, and have limited experience with straight cuts as well. I have googled, and found an article where the writer is talking about turning the glass over so the score is on the underside, placing it on a piece of cardboard, and applying pressure to the score from the back.

Will this get me the desired results?

Reply to
js
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If you are wanting to end up with a half moon shaped of glass, the inside round cut will be tough. You want to remove as much of the glass before scoring the arc with your glass cutter. Score the line as usual along the arc and make a few relief cuts out perpendicular from that arc. Then gently star breaking away. Generally I use grozing plyers to naw away up to the arc. If you are wanting to end up with an outside radius cut, similar to a ball, score the arc with the glass cutter and let some of the scores go straight so that you can break away several pieces as you go around the arc. PRACTICE FIRST. This took me several tries to learn especially with the 1/2 moon cut.

Reply to
Leon

As far as breaking the glass, I prefer to keep the keeper piece on thin cork or an old spread out bath towel. With the scored line up and near the edge of the table quickly press down on the unsupported waste part of the glass. Remember to make relief cuts as the glass will want to break straight and this arc cut should be made in about 4 cuts.

Reply to
Leon

awesome. thanks for the advice.

Reply to
js

nonsense. 1" in 10" is practically straight. cutting it off in pieces would cause flares, and i would assume that the OP doesn't have the diamond tools to fix that.

this can be cut in one go. you can get some scrap window glass for FREE at window places. they toss out lots.

use a sharpie on the back side to mark your cut line. paint the top surface on the curve with kerosene for a lubricant. run the cutter over the line, staying on one side of the sharpie line or the other, but be consistent. use a firm, but not a heavy head. you want to hear a zing, not a crumbling of the top surface of glass. it doesn't take much with window or even double strength glass.

run the cutter to the edges of the glass.

there's two ways to break it. 1: place the cut side down on a piece of rug. press downwards at the end of the cut with the end of a rounded wooden dowel. it should start to run the crack, and will follow the break. 2: with cut side up, hold between your thumb and first finger knuckle of each hand. pull down and away with each hand.

there are glass tools that make this a lot easier. you could also just take the glass (marked) to a stained glass place. it'll take about 30 seconds to do this.

Reply to
Charles Spitzer

It certainly will break easier with the relief lines added in. Better to not take the chance. I have done several stained glass projects and this is the correct way. Further if the edges are going to show, you can sand the edges to smooth them up, however I usually do use my wet diamond glass grinder.

Reply to
Leon

As a bit more of an indicator, if that arc that is 10" ling with a 1" rise were extended into a circle, the radius would be 13". The edge of that circle would hardly be close to practically straight IMHO.

Reply to
Leon

Umm, one more thing here, you are partially right to advise using a lubricant but,,,It is not for the glass. It is common to dip the cutters into a lubricant to lubricate the AXEL that the wheel spins on. All of my glass cutters have built in lubricant dispensers that lubricate the axel and wheel when the cutter is depressed down on the glass. This extends the life of the axel.

Reply to
Leon

the radius is 13" whether you extend it at all or not....

it looks plenty straight enough to cut in one shot to me....

Reply to
bridger

LOL.. That too.

It does not sound like much curve until you realize that the rise is 1" half way though the arc and not a total of 1" at the end of the 10" run. So the

1" rise happens at 5" into the run assuming the arc will form a circle. The waste side of the glass will more than likely break somewhere. When working with the more expensive stained glass you tend to want the scraps to break such that you can get more pieces from them also. Making the relief cuts where you want helps insure that the scrap will be useful also.
Reply to
Leon

As someone who make stained glass panels I agree with the advise above. I would also suggest getting a good glass cutter that automatically oils the cutting wheel while the cut is being made. When cutting the glass don't draw the cutter towards you. Use a push cut moving away from you body.

-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)

Reply to
Nova

The oil serves two purposes.

From the Warner Crivellaro web site (

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):

Lubricant - Glass cutting lubricant or oil is generally a half and half mixture of kerosene and a light oil. This cutting lubricant serves to clean off little slivers of glass that cling to the wheel of your glass cutter and interfere with the wheel spinning freely. It also helps prevent the score line from sealing itself which can prevent you from breaking the glass even though the score line is still visible. Commercially prepared lubricants are available.

-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)

Reply to
Nova

did I miss something here? I think the OP was talking about plain window glass. of course, with anything else it'll be harder.

Reply to
bridger

Well, hummm,, My instructor 20+ years ago mentioned that the oil was for the wheel axel. We never really saw much oil on the glass at all. As for the score line, he told us to break the glass ASAP after scoring.

Reply to
Leon

Listen to Leon !!! I agree with what he says. I have 20 plus years in stained glass (hobby only ) from lamps to windows etc. and oil lubricant is for the cutter wheel. Inside curves are very difficult to cut. Depending on the glass sometimes you have success sometimes you have a oh ! sh--!!!! I would cut the glass oval in several steps (small curvatures). The trick to cutting is even steady pressure of the cutter on the glass and seperate the pieces in slow rocking motion , this enforces the score line and seperation at the line. I would also get a diamong stone to smooth the edges of glass.

Reply to
dteckie

sorry, i've only been doing art glass work for 20 years, so i'll bow to the greater knowledge of someone who as a few stained glass projects under their belt.

a 10" piece of a 26" diameter circle is practically straight. yes, it may break easier, but it will be vastly harder for the OP to clean up the edge afterwards.

btw: you want to get the fewest, and largest, scrap pieces. the OP probably doesn't care what happens to the scrap, since they'll probably be discarding it anyway. doing relief cuts on this is piece is silly and wasteful. for all practical purposes, it's a straight shot. furthermore, since it's an outside cut, if it runs, it will run off as a relief would anyway, thus producing your relief cut. single window glass is very soft, and this type of break is simple to do.

you want a hard thing to practice on? try cutting a 2" circular diameter hole out of the middle of a 14" diameter circle of white stained glass.

Reply to
Charles Spitzer

well, a: you don't have or know of all cutters. there are some that designed to cut dry. for instance there are some carbide wheels, and diamond tipped hand cutters, that are like this.

b: second, it's not only for lubricant, but to help with the selfhealing properties of the glass skin. i've been cutting stained glass for years with a dry cutter. when i cut 3/4" glass, it's far easier to paint on kerosene with a paint brush. cutting 3/4" glass won't break correctly without putting something on the glass surface first.

Reply to
Charles Spitzer

On Tue, 27 Jul 2004 09:14:35 -0700, "Charles Spitzer" vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

As an interested standby reader of this thread, who is trying to learn, I would politely ask that you stop attacking Leon. He expressed an opinion and you denigrated it ("Nonsense"). He continues to politely talk it over and you start getting sarky.

***************************************************** It's not the milk and honey we hate. It's having it rammed down our throats.
Reply to
Old Nick

It would seem to me that 20 years experience _does_ trump "a few projects".

Reply to
Dave Hinz

It should, but there are always exceptions. I know of people that have been hacks for years and still make a living in their trade.

Reply to
Edwin Pawlowski

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