Monday, June 20, 2011

Last Week in the Gazette the “Pull Test” was described for cased perfume flower stoppers(see below). Marshall Ketchum adds to that discussion.

Alan

There is a bit more to the pull test than stated. The two rods would be parallel and melted together and then pulled out into a fine thread. A mismatch in the coefficient of expansion would bend the thread in one direction or the other when it cooled. The amount of bend or defection was a measure of the mismatch and Carder had pre-calibrated how much of a deflection was allowable before the glasses matched too poorly to use together.

Marshall

Perfume Bottles with Floral Stoppers:

Mirror Black and Turquoise

Gold Aurene and Cinnamon

Blue Aurene and Turquoise

These perfume bottles are not only beautiful to look at they are also functional. The colorful floral stoppers were created using a casing technique. Casing is the layering or “casing” one color of glass with another. In order for this technique to be successful the glass being layered must have a similar expansion rate when cooling, this can be discerned through a “pull test”.

Technical Note: The pull test that Carder would use is this– create a rod one-quarter inch in diameter and 6 inches long of each layer of glass; the two rods would be melted together; as they cooled the laboratory technician would note whether or not the rods remained straight (signifying compatibility) or if one rod would bend more than the other (signifying incompatibility). Depending on the results of this pull test, the glass formulas would be adjusted and production could continue.

www.cardersteubenclub.org

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

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