Glass Cutting
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Hello all 🙂 First off, sorry if this is in the wrong section. It didn’t seem to fit in any other.
Today I made my first attempt at glass cutting. It didn’t go so well. I scored my line with a standard glass cutter, but had a devil of a time getting it to split. After it did, it soon began to chip really bad, so now I’m left with an almost serrated edge on my piece of glass.
What would be the best thing to smooth out the jagged-ness of the edge? I tried sandpaper on a block, but it didn’t last long. I’m thinking of trying a needle file next, but wanted to get some more educated opinions first.
Here are some pictures of what I have going on.
#1 shows the jagged edge and the score line I made. This was my first ever glass cut.
#2 shows the next three cuts I made. Still have a rough edge in spots, but getting better at it.
#3 shows the best one I’ve cut so far.
#4 shows what I’m going to do with the glass when I’m done. It’s a vase that I cut out on the scroll saw a few years ago, but then I had the bright idea (no pun intended) to turn it into a candle holder. I’m going to use a small LED light for the flame, though. The glass is going on the inside.I’ve also made a temporary pair of “crimpers” (don’t know the correct term for this tool) from an old set of pliers with duct tape wrapped a few times around the jaws. This helped greatly on the smaller pieces near the edge.
I’d like to see some tips for glass cutting as well.
@Ben, have you seen Paul’s glass cutting video in the tools and technique videos?
Keep practicing, George, you’re making good progress! I had to cut glass on a job years ago in a factory, working my way through college. I ruined a lot of glass. I don’t know if I could still do it today, even though I cut hundreds of linear feet of the stuff back then. It can be tricky. Glass seems to me to be “grainy” like wood in that it will sometimes just take off on a tear off your cutting line along an imperfection or an air bubble or something.
George, One tip I can offer is to have a really good glass cutter. And only score your glass one time. The first couple of times I tried it I wanted to make sure my score was deep enough and went over it several times. I got the same results you are talking about. You can smooth up the edges with a little emery cloth. Glass cutting is an art in its self. Practice practice practice!
What Sandy said.
Two more tips are to clean the glass before cutting it and to lubricate the glass cutter. That helps avoid small skips in the score line, which can cause the glass to break unevenly.
Thanks for all the helpful replies 🙂 I ended up using some 80-grit sandpaper and the skinny side of a course sharpening stone to smooth out those edges. It took a bit of time, but it went ok. I think what Sandy mentioned is what happened to mine. I scored it more than once. The first straight edge I used was less than ideal, so the cutter kept sliding off to one side. I did watch Paul’s video and remembered to lube the cutter. I didn’t think about cleaning the glass as it had just come from the hobby store still wrapped in plastic.
Here’s the final product… well, 95% of the final product. I’m not sure which I like better yet. The LED lit one actually looks brighter in the picture than it does in person. I think if I shorten the LED mount it might look better. The candle lit one looks awesome with the flicker going on, but I worry about fire hazard and it’ll be a bugger to take apart and clean when all that wax melts to the bottom.
George,
The best way to smooth off the edges is to use a coarse oil stone, this will bring the edge off easily, but don’t use you best one, as it may groove the surface. I use this method to take off the Arises before fitting glass to a project as a matter of course.
Good luck.Cut the glass on a flat surface. The surface should be covered with something like an old piece of carpet/rug, not a deep pile one though. Use a good glass cutter. score the glass once only. if the cutter sounds like a machine gun as it score the surface or seem to be sliding rather than rolling over the glass, change it, or use a new wheel if you are using a multi wheel cutter. There are a number of ways to open the cut, it depends on the thickness of the glass and distance from the cut to the edge. For most glass up to 5mm or 6mm and with about 10″ or more either side of the cut; the cut can be opened by placing the sheet of glass on the edge of the bench/table (whatever you are cutting on) with the cut no more than 3mm back from the edge. Then, press down gently on the glass where it rests on the table and holding the other edge glass with the other hand, push down firmly and quickly. The glass will break cleanly along the cut.
If there is less than 10″ and more than 2″ between the cut and the edge, place a narrow and thin (no more than 6mm) piece of wood under the glass so that the cut is in the centre of the top surface of the wood. Press down firmly and evenly on each side of the glass and it will break cleanly along the cut. If your piece of wood is shorter than the length of the glass, place it equidistant from each end of the cut.
If you are taking less than 2″ off the edge of the glass, but more than 1″, sharply tap the under side of the cut at one end with the glass cutter, there is usually a head on the end of the handle of the cutter for doing this. If you are using a wooden handled cutter, use the metal part where the wheel/s are. The glass will crack along the cut for a 1/2″ or so. It does not take much power to open the cut this way. Now, either slip a narrow and thin piece of timber under the edge of the glass as described above, but only about 1/4″ / 1/2″ should be under the edge, then press down on both sides of the cut near the edge of the glass. If you apply the pressure gradually, you will be able to see the cut opening along its length.
If you are taking less than 1″ you can tap the underside of the glass as above and then use one of the notched in the head of the cutter to bend the glass and open the cut. Hold the glass so that the 1″ or so of the glass is over the edge of the bench, slip the glass edge into the notch in the cutter (handle pointing straight up), next to the point where you opened the cut by tapping, this positioning is important. then pull the handle of the cutter like a lever and the cut will open. If the glass is too thick to fit the notch you can use a pair of pliers to grip the glass. Make sure you have a piece of thin cloth between the metal of the jaws of the pliers and the glass. You can get special glass pliers for this, they have jaws that are about 1″ wide so have more surface contact with the glass and spread the force. Inside the jaws of the glass pliers there are small grooves. These pliers can be used to grind off the “waney” edge you get when opening the cut by tapping.
If you want to know how to cut a round hole in a sheet of glass, I can tell you how to do it. No its not like you see in the movies. Pulling a disc of glass out of a window is impossible and you cant open a cut from the same side as you score it. You cant cut glass that has been toughened by heat treatment either. You can cut laminated glass with a hand cutter, but its tricky.
Finally: never try to catch a piece of glass if you drop it, you will get cut.
Thanks for the info, Gooner 🙂
Hello,
I am a commercial glazier by trade. I have almost 15 years of experience working with glass in all different types and thicknesses.
The problem of having a jagged edge could be helped in a few ways. First off, glass should not be too hot or too cold when you score it. Try to avoid extremes.
Second, avoid the basic steel wheeled cutters. Spend the few extra dollars to get the diamond one. A good one will also have a place to pour oil into it.
Make sure your line is free of even the slightest debris.
My last bit of advice is not to press so hard. One continuous, firm, score line. No starts and stops. If the glass sounds like it’s cracking, you have what we call a “hot cut”. You pressed too hard.
Have fun.
Kevin, do you ever use the pliers designed to break glass?
Dan, I do use a couple of different types of pliers when to run my score line. Glass that is 1/4 inch (6mm sox) or less can usually be done by hand but there are circumstances when they are handy. And probably safer. They’re not great for cutting laminated glass though. That’s a bit of a different technique.
Good to know 🙂 Thanks, Kevin
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