why won't the glass break follow my score???

I'm embarrassed to be posting this. I've been doing kiln-formed glass for 5 years now and suddenly I can't get a single piece of glass to break along the score line. I've tried using 3 different glass cutters (all Toyo) and even 3 different breakers, but every piece (Bullseye COE90), both opal and transparent, even Tekta won't break correctly. I've only been trying to cut straight lines, haven't dared attempt any curves or circles. This has been for the past week! The heat is on in my studio, so the glass isn't really cold. What else can it be? What can I be doing wrong??

* Do you by any chance have tendonitis affecting how evenly you maintain pressure while scoring?

* You culd hav a look at my tips blog (use the search term "scoring glass") for some suggestions, but the best document to review is the Bullseye one on scoring at:

* Sometimes due to frustration with glass is not breaking right we press harder on he cutter. This will always cause problems. Cut on a scale and determine the correct weight you need to score. If this is the problem you will feel yourself relax into the correct pressure that you have always used. Georgia

* I suggest you get a more experienced glass cutter to observe you. Something isn't being done right, and it is impossible to tell from your post. You ruled out some of the answers, but there are so many factors.
You can look at the edge of a successful cut. If you pressed too hard, there will be deep striations. If you press too lightly there will be no striations. I'll guess maybe you are pressing too hard?
Be sure to clean the glass before you score.
If you are running the score, start from the edge where you finished the score.
Read lesson 1. It is a really interesting description of how glass breaks from a score.

* Been there too. I was pressing too hard----again!! Stand right behind the score and exhale before you start the score. Also, could you need new tips on your breaking pliers? I just changed mine and it made a difference.

* Check the adjustting screw on your breaking pliers maybe its turned and not allowing you to put enough pressure on the glass...I've seen this happen.

* After a lot of years I have developed the glass cutting equivalent of a golfer's slice. If I don't pay very close attention, I begin pulling the cutter sideways when I am using my Morton system for cutting straight lines. It is very obvious when I do this, because the score becomes wider and I can feel the cutter drag. The glass does not follow the score and acts like I never made the score. To offset my "slice" I am now much more focused when I make the cut and sometimes I just lean back to pull the cutter with my entire body rather than just my arm. I tried different cutters, but in my case the problem is me not the cutter.

* I had been cutting Bullseye 10x10 sheets with out problems for several years. Even bigger sheets of float glass didn't give me any problems. Recently, I bought several sheets of Bullseye half sheets for some projects I had in mind. The first half sheet of double rolled I did, shattered on me along the score line the first two attempts I tried. As far as I could tell, I was cutting them the same way I cut the 10x10's. So I asked for help too. There were several suggestions I got when I asked for help that now have me cutting the half sheets as well as the 10x10's 98% of the time. One was to make sure the glass was clean where I was cutting, use less pressure (this I have to conciously remind myself along the whole cut) and the one I got from Bert to paint the score path with cutting oil first. I find I get a much cleaner score when I oil damp piece of paper towel down the straight edge I use. Now if I could just learn to automatically ease up on the pressure all the time, I'd probably make 100%.

* Be sure you are cutting on a flat surface. I find it helpful to hold the glass cutter vertically. You would think that tilting the cutter like a pencil or holding it vertically wouldn't make a difference, but holding it vertically seems to give me better control.
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA

* What helps me, besides all the above suggestions is to (1) support the glass on something slightly padded and level-flat, like a piece of carpet, (2) relax. The relax is especially important. The more unconscious I am of the score, the better the cut. When something went wrong the first time and I'm really concentrating on the second, I tend to push the cutter harder AND slower, and have a lot more trouble.
I'm honestly not sure why that causes a problem, although I do know it chews up more of the glass and so there are more chips clogging the line and the cutter. Nowadays if I have a bad break instead of the line I was scoring, I go somewhere, change the music, have a drink, return a phone call, etc. When I come back to the cutter I start with a different piece of glass, and THEN come back to the one I'm having trouble with. I don't think, just score, as fast as I can. Usually breaks just fine and my rhythm returns.

* Be sure you are cutting on a flat surface. I find it helpful to hold the glass cutter vertically. You would think that tilting the cutter like a pencil or holding it vertically wouldn't make a difference, but holding it vertically seems to give me better control.
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
Arnold reminded me. If there is a dip in your cutting surface, it is impossible to accomplish a run no matter how good the score is. No problem if it is convex in shape. It is highly likely that if you put a straight edge on your cutting bench, you'll see a dip,

* Been piling 'things' on the cutting table when not cutting glass?

* Thank you all for your great advice. I've been trying it all and checking out your suggestions. I even had another really experience glass artist watch me and try it herself and it seems it's been a combination of errors. Some of the glass itself was warped or had other flaws in it. Also, two of my cutters had new cutting heads on them, but when I switched back to the old ones, they worked a LOT better (another glass artist complained about the same thing, her new Toyo head was not scoring her glass) Still, what usually is not at all a problem for me, cutting glass, has suddenly become a struggle and quite frustrating. I'm exerting even, moderate pressure, the score looks fine, I don't have tendonitis, I'm relaxed, I exhale, etc, etc, but still the actual break goes off into la-la land.
But I copied all of your suggestions and will keep them handy to remind me of how to help ensure better cuts.
Thanks again!!

* Using cutters is like the aging process. We and cutters change. As the cutters get older they get duller and need more pressure, the adjustment is so gradual we do not notice. Put a new head on your cutter and wow it does not need the pressure the old used one does. As with life, things change. Try the scale and make note of the pressure needed with your new...or old...cutter and become aware of the gradual change. Georgia

* I'll repeat: A perfect score can not work, if you try and run it on a concave shaped bench. If having trouble, put a straight edge across your breakout surface, and check. Find a flat surface, and it will work just like you pictured it.
The wheel stuff is all right on, but a wide range of pressures will result in a successful break. On the other hand a skip in the wheel will fail most every time. The old steel wheels get skips. I've never had one on a Toyo wheel.
I am a fan of painting my glass with kerosene before scoring. When fusing, you have to clean the glass. I skipped this when I copper foiled my edges. but there is no point in skipping it, once you will be cleaning anyway. Fusing glasses do not necessarily require this. Float, on the other hand, does.

* an old stained glass friend and owner of a glass supply shop... now passed away... said when he was starting out in making stained glass windows as an apprentice... the owner would get the workers to cut strips of float for 20 minutes before they started on the stained glass.... they would have gotten their rhythm down for the day without sacrificing expensive glass.

* Something simple to try. Make sure that your cutter head is screwed in properly and not allowed to wobble when you begin your cut.

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