Jeremy Hayes Asked Whether Cintra Is Unstable

Alan, The left one , green. See cracking coming up in front of base from dark leaves shape. The other with the Greek Key decoration. See the crackling throughout but especially in pink area just below the shoulder. Maybe its just the pics? Thanks. Regards, Jeremy Hayes

Coefficient For Expansion

Jeremy Hayes, there is always more of a problem with cracking when you encase glass or combine glass of two different formulas next to each other. Different formulas of glass expand and contract at different rates and different volumes. This is a recipe for disaster. The two glasses must have the same coefficient for expansion in order to “work together”. This was always taken into consideration by the blowers and by Carder. A simple stretched rod test could easily be performed where the two or more types of glass were placed together and stretched into a long thin thread. Much like two railroad tracks touching each other side by side. It would then be allowed to cool and be inspected for any cracking. Adjustments in the formula could sometimes be made to minimize this effect. Rande Bly

Various Types of Cintra

Cintra production can include one, two and three colors, shading effects, striping, etching, brilliant colors, soft colors, matted, cased, uncased, bubbles and no bubbles.

abstracted from Collector’s Favorites #63 by Bob Mueller