Dr. G. Jane Cook is the chief research scientist at The Corning Museum of Glass. In addition to her responsibilities researching and sharing scientific and technical topics in glass, she is also the scientific advisor overseeing the new Specialty Glass Residency Program offered by The Corning Museum of Glass and Corning Incorporated. In December, Dr. Cook hosted world-renowned artist Albert Paley, the first artist selected to participate in the residency program, and generously agreed to share her experiences in a series of blog posts, which we’ll be sharing over the coming weeks.
It was our great pleasure to host Albert Paley at the Museum for four days in December. A blacksmith and metal sculptor, Albert has explored the interplay between glass and metal in his work for two decades. As the first participant in the new Specialty Glass Artist-in-Residency (SGAiR), he was chosen by the Museum to work with technical glasses, advanced processes, and glass scientific and engineering experts from Corning Incorporated.
This was Albert’s third visit to the Corning area as part of the Residency. The first two engagements (in May and August) were held at Corning’s flagship Sullivan Park research and development campus a few miles from the Museum. Over the combined three days of those visits, a half-dozen glass formulations were discussed, and experimented with, in ways generally consistent with Albert’s aesthetic vision. Albert chose to work primarily with a glass that could bond directly to metal, previously known only to a small group of materials engineering specialists: Corning Code 7056, a borosilicate glass that was first formulated and sold in the early 1970s for semiconductor packaging and precision optics.
Prep for his Visit
A half-ton of 7056 glass was melted and formed into cullet at Sullivan Park, according to a precise recipe that would ensure a well-mixed glass that would bond permanently to the metal.
Three furnaces were then prepared to re-melt and contain the 7056 at the Studio: one 500- pound gas fired unit, and two “mini-melters.” The plan was to have the large melter available for the gathers, and the mini-melters (which have a lid that swings aside to allow vertical dipping of a form up to 12” wide) to be available for casing, and for direct dipping of metal pieces (so that if metal dropped in, only a small amount of glass would be spoiled). The latter were given fresh crucibles, but the large melter needed to be thoroughly emptied of residual sodalime and “washed,” that is, it needed to be charged with enough glass to fill the bottom and allow the walls to be manually coated – about 100 pounds – and then have that glass gathered and scraped out. This needed to be done three times, before the “good glass” for working with Albert could be charged and melted.
The gas-fired tank created another complication. Borosilicate glass, when molten, are prone to “volitilization,” that is, the evaporation of some of the elements from the glass, particularly boron. As boron leaves, the surface glass with less boron behaves differently from the rest of the mass of glass – it is stiffer, and a bit hazy. The constant motion of hot gas from the burners across the surface of the molten glass pool strips away boron more quickly than it would be lost from a more quiescent type of melter. To work with this phenomenon, to make the tank work for this engagement, it was necessary to watch carefully for the buildup of boron-depleted glass, and to “rake” or push the scum away from the part of the pool from which the glassblowers gathered.
Read more about Dr. Cook’s experience working with artist Albert Paley next week.