Because they are made freehand using no molds, there will be variations in size and shape. On average, the penholders are roughly 3 - 3.5" tall, with a base about 3 - 3.5" in diameter. The average weight is roughly 8 ounces. Some run a little smaller and some a little larger. If you have a preference for something on the larger or smaller side, please let me know when ordering and I will do my best to accommodate you. (My experience has been that some people like the larger ones because they seem more substantial, while others like the smaller ones due to their slightly smaller footprint on a cluttered desk. All of them can do double duty as a paperweight, as well as a penholder.)
The majority of the glass used for my penholders is glass that I have formulated, then mixed and melted myself from sand, soda ash, lime, and various other glassmaking chemicals. I adjust my glass compositions depending on what colors I want to use, and the working and melting characteristics I desire. The melting temperature for most of my glass recipes runs between 2300 and 2400F. The working temperature is a few hundred degrees lower. In addition to my own glass recipes, some colored glass I use is purchased from a few suppliers specializing in studio art glass.
Along with formulating and melting the glass, I personally designed and built virtually all of my own glassmaking equipment, including the glass furnace(s), annealing ovens, and the control systems for them. My primary glassmaking furnace is an electric furnace that I designed and built in 2010, which has a capacity of approximately 100 lbs of molten glass. I designed and built my first electric glass furnace in 1994, long before electric furnaces became popular among glassblowers. That furnace, which held 225 lbs of glass, was still running strong when it was finally dismantled in 2007, immediately before I moved from Alfred, NY to Georgia. Prior to 1994 I used a gas-fired furnace. Silicon carbide heating elements are the type of element I chose to use in both my first, and current electric furnaces.