Sunday, May 01, 2011

Last week we should a piece of dark jade blue Carder glass that was exhibited at the University of Southern Indiana. The description of the glass prepared by Susan Colaricci Sauls, Art Collection Registrar read as follows:

Dark Blue Jade Vase with Optic Ribs

Lead Glass

Few pieces at Steuben were created using only molds and if a work was molded, it would receive much hand work when removed including polishing the rough edges and finishing the surface. This vase was blown into a 16 rib paste mold and then given a satin finish.

Technical Note: The paste mold was created with an iron mold coated with a paste made of boiled linseed oil, burgundy resin and beeswax then sprinkled with apple wood sawdust. The mold’s coating was dried and baked until it was a rich brown color. At this time the glass was blown into the mold creating a smooth glass surface that was burned to form a carbon coating. At the peak time the mold was dipped in water creating a steam layer between the mold and glass to remove any mold marks. When the work was removed it had a smooth surface.

This description raised questions about its source and other technical questions. Susan begins answering with:
Alan,

· If this is the work discussed then this is where I found the information…

·

· The glass of Frederick Carder, by Paul V. Gardner. Introd. by Paul N. Perrot.

New York, Crown Publishers [1971]
Pg 90
The mold itself was metal but was coated on the inside for the desired effect of a

Susan Sauls

Then Jim Sutterfield of Corning, NY gives us a more precise and detailed response on the molding process.

Hi Alan: Let me give a shot on the glass forming questions. On the blow molds, the explanation yesterday is correct. The mold usually consists of two halves,they have paste applied then cover that with a material such as cork then oven cure. To use you wet the mold, insert a gather ,close the mold halves then rotate the gather against the steam created from the hot glass and the water absorbed in the cork. When the shape is obtained, open the mold halves and continue finishing.

In Carder’s molding the gaffer is still very involved because he still makes the gather (gob weight),transfers to the press station where the gather is sheared into the mold. Above the mold will be a plunger that will be somehow aligned to the mold and arranged in a toggle leverage system to press the molten glass into the cavity between the mold and the plunger. If you look at Carder’s pressed items you will notice the rims are ground and finished and my guess would be that the same item side by side would show quite a variation in height because the gathers (gob weights) in hand operations will vary.

Hopefully these make some sense. The automated systems now in use are several steps refined from above in controls.

Jim

Finally, Michael Krumme of Los Angeles raises a satiny question.

In addition, I was wondering why the piece was described as being satinized. Clearly, based on the photograph, this piece is not satinized… at least on the outside.

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2011 Carder Steuben Club annual Symposium will be held at The Corning Museum of Glass in Corning, NY from September 15-17, 2011.