Today I learned I was way off base about the use of the grozing iron. I'm a little embarrassed to write this, but this blog is a place for me to track my findings, sources, projects, etc. I know others read it, and I link others here when something I've found may help them... but at its core it's my own record keeping. So, today I learned that the grozing iron is not grozing pliers in a different shape.
It wasn't just the name that led me to think this, but a slight underestimation of the tool's capabilities. I understand and understood that the dividing iron acted as a glass cutter and running pliers in one; it creates a score that runs pretty much simultaneously. I thought that the grozing iron must be there for lines that don't quite break, or for glass that is leftover on a breakline. I tested the tool that way, running a score and confirming that, yes, it breaks the score.
However, that's not what gives period glass it's distinctive chewed appearance, and not why the tool is described as nibbling glass. Tonight I cut a few pieces of my panel with the dividing iron and noticed I could only cut some general shapes out, not the exact pieces I planned. I reviewed some notes, sources, and reconstructions from a tourist attraction in the UK and suddenly it clicked.
You are literally chipping away little bits of glass with the grozing iron. It uses brute force to chew bites off the glass, a description that suddenly seems a lot more on the nose when you are looking at all these tiny semi-circles taken out of an edge. I was also surprised to find that the tool is quite versatile. I can tear off large chunks indiscriminately, and I can also scrape slivers off.
So, today I cut most of one blue/gold border. According to the museum notes these panels were silver stained. It looks rather even and its the entire piece in all of these borders, so I assumed it would be pot metal yellow. I'm trusting the experts, however, that these were stained.
A grozed piece in place
The border, missing two pieces
The picture above shows a side effect of using a dividing iron; There is a lot of uncontrolled cutting and breakage. Unfortunately it is very difficult to get the blue GNA glass I'm using here, and the clear mouth blown is expensive. I don't think I'm going to be able to maintain my goal of extensive period cutting. I will use it whenever I can, but I'm already accepting the fact I will have to use my modern cutter in many places just to avoid wasting hundreds of dollars of glass, some of which I can't even replace if I have to.
I'm saving the little pieces on the corner of the table to potentially make a small batch of vitreous paint. I have a late period formula that calls for iron shavings, which I have on hand. It will make for a fun little experiment. I don't have to worry so much about incompatibility if I am using the same base glass... I hope!
A close up of a piece while I worked on it, showing the characteristic nibbles
All in all today I got a first true appreciation for the work of a medieval glazier. I am making a 1 square foot scaled down version of a segment that would have been 4 square feet. If I do the math, and if memory serves, the entire window would have been 36 square feet. It was one of 5 windows in that portion of the church. One of several dozen windows in that cathedral.
And they made it with a hot iron rod and a bar with a notch in it, in essence.
Ho-ly { ..... }
The enormity of it boggles my mind. They could do so much with so little in the middle ages.
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