Thank you for your question! According to our research scientist,
Glass gall/sandever is rare. In modern glass production the raw materials that are charged into the furnace (“the batch”) are very carefully controlled by strict quality control measures. Ingredients that would produce gall (e.g., chlorides and sulfates of sodium or potassium) are scrupulously excluded if possible; and if they are charged (as fining agents or colorants), the actual amounts are at levels far below levels that would lead to gall.
The exception is for operations that try to make usable glass by charging a combination of known-quality glass batch or cullet with various hazardous waste streams, such as demolition wastes containing asbestos. These less-controlled ingredients can contain significant amounts of materials with limited solubility in the glass melt, like sulfates and chlorides, that then float or sink (depending on their densities when molten) to form a top scum layer, or bottom sludge. Special provisions must be made in the design of the melting furnaces that do this kind of work, to enable the skimming or draining of the gall. An interesting side note, that you may be aware of, is the use of the term “gall” for this material likely derives from the fact that the fused, cooled sulfate-containing salt would be bitter to the taste – “galling.”
I regret that I am not familiar with any manufactures of this type of glass material, however, that would have gall available. I am unsure, actually, if the glass itself would need to be treated as hazardous waste. Perhaps the information above can be a lead to help you find someone in your area who is doing hazardous waste vitrification.
Another option that you might consider is to contact glass artisans who specialize in historical recreation of historical glass melting techniques.
Additional avenues for research
- The Scholes Library at Alfred University, New York State College of Ceramics. They have a substantial collection of technical information about glass. Their reference desk number is: (607) 871-2951. Alfred’s library catalog is available for searching on the web.
- The Glass Division of the American Ceramic Society (Columbus, Ohio)
- The American Ceramic Society, P.O. Box 6136, Westerville, Ohio 43086-6136 ; Phone: (614) 890-4700 ; FAX: 614/899-6109 ; email: info@acers.org
- The Society of Glass Technology in Sheffield, UK: Don Valley House, Savile Street East, Sheffield S4 7UQ, UK ;Tel: +44(0)114 263 4455 ; Fax +44(0)114 263 4411 ; e-mail: info@sgt.org
