My weekend project was to collect enough old glass to glaze the sash doors. I almost have enough and got more than half of the pieces cut.
I have 40 small pieces of glass that I need to cut to fit up the sash doors on the secretary. I have selected antique glass for the restoration and that presents certain situations. For one thing the glass is old, not that that is a bad thing but it is not flat nor is it the same thickness throughout, let alone the contained seeds and grains. There is also the putty, paint and dirt that must be properly dealt with.
Now I was instructed by a professional Art Glass Master, with a speciality in Glass Restoration, and his name I will not mention as he probably doesn’t want this type of association. He instructed me that the best glass cutter has carbide wheels which should be replaced on a regular basis. He said that the cutter should be lubricated (the only instruction I followed). Cut one continuous cut and don’t go back over the cut. He uses a marking pen to mark cutting lines on his glass. He also said that it was important that the glass be clean with all surface accumulations removed. This can be easily done with a sharp blade such as a single edge razor blade.
Some of his instructions and recommendations are simple things that we may not think of, such as having a flat surface to work on, keeping it clean, throw the scraps away immediately, don’t brush the work surface with your hand, use a bench brush and keep some bandages close.
Well as you may be able to tell, I do it a different way. In the first place I own currently (I have sold some nice old ones) a fine diamond glass cutter. It has a 1/4 carat industrial diamond set in a copper bezel set in an iron head on a brass ferrule and birch handle. I do use oil to lubricate every cut and that little piece of paper towel has a few drops of light machine oil, but bear fat or lard work fine as well.
And I don’t bother cleaning the glass unless I can’t lay a straight edge on the glass and only clean off glass that actually survives the cutting process. No reason to clean of glass that is going in the garbage. And because the marking pen didn’t exist in the nineteenth century I used a stained glass technique of making a cartoon (full size drawing) of the glass I need on some white paper.
I place the glass over the drawing of the size I need, position the straight edge so it is offset the distance of the diamond point is from the edge of the iron head. Get comfortable with the offset of the diamond and it becomes easy to just visualize the proper distance, then hold the straight edge down tight and make the cut from the far end to the near. I am going to try to cut some freehand without a straight edge, I have seen this done on smaller pieces.
Sometimes the cut doesn’t start just at the far end but cuts to the end just fine. I was told not to try and finish the cut, but I didn’t listen. Instead, I reverse the glass, register the point of the diamond in the existing cut, just like placing a chisel in a gauge line, and continue the small cut off the edge of the glass.
After the cut is made the glass is reversed and it is struck with the end of the cutter on the opposite side of the cut.
I tried tapping it with the iron head with its rounded edges and it did work but took some time. So I tried turning the glass cutter around and used the round wooden end to do the fracturing. I was amazed how easy this process worked.
On these small pieces a tap or two and the waste just pops off. Sometimes you end up with a cross fracture or wayward crack that ruins the piece or that runs out requiring some nipping with a pair of pliers
Here is what the fracture looks like if it doesn’t go completely across the piece. The fractures usually start at one end, but that can start in the middle of the piece, the unusual characteristics of glass. Watching the fracture move along is fun, until it runs out and ruins the piece.
I cut 24 pieces and still need to cut another 16 pieces. I ruined about a half a dozen pieces, about half of which I could get smaller pieces from. I start out cutting the larger panes then cut the smaller. But there is more waste when cutting antique glass, modern single and double strength glass being more uniform in nature usually get better results.
Once I have them cut then I will use a flat chisel to remove the putty and paint that is still remaining, clean with alcohol then vinegar. The glass in the sash doors will be held in with triangular points and glazier’s putty.