H. C. Fry Glass Company, Rochester, Pennsylvania

HEAT RESISTING GLASS DISCUSSED

AT MEETING OF PITTSBURGH CERAMISTS

About 30 members of the American Ceramic Society — Pittsburgh Section — met at the Bureau of Mines, Pittsburgh. Pa., on May 16 to hear a lecture on the manufacture of heat-resisting glass. J. W. Cruikshank, of the J. W. Cruikshank Engineering Co., of Pittsburgh, presided. In opening the discussion period, he made a plea for a wider interest among members in the Pittsburgh district. Suggestions were made for the reading of papers of a less technical nature, for more publicity, and for freer and more informal discussion — matters which would tend to benefit those present who were not technical men. It was also planned to hold a meeting at East Liverpool, O., at some future date. Over 100 members of the society are residents of this pottery center.

E. H. Hughes, of the H. C. Fry Glass Co., Rochester, Pa., who has been engaged for some time in working on heat-resisting glass, discussed the development of this glass for high voltage insulators, for the manufacture of spark plugs, and for use as cooking ware. Mr. Hughes said cooking ware manufacture has reached a stage where attention is being paid to its decoration. Several samples which the speaker offered, including a casserole and a percolator type coffee pot, were of a greenish iridescence with a cut flower design. Such glassware is widely known at the present time, but Corning Glass Co., with its "Pyrex" and the Fry company with its ware, spent years on such glass — free from all stresses and strains, heat-resisting, able to withstand temperature changes and resist the action of liquids or solids without introducing alkaline impurities into the food or drink.

Development of glass cored spark plugs was the second point touched by Mr. Hughes. These plugs use the same metal parts as are used in the porcelain plugs, but certain claims are made for the advantages in using the glass core. Plugs are pressed in a mold, directly from the glass, and with each pressing operation four plugs are formed. It is claimed that these cores will withstand a cylinder compression in the automobile engine of 225 pounds, while the porcelain core shatters at some 70 pounds. It is further claimed that no carbon will form on these plugs. Other advantages lie in the ability to see the explosion. The deep bluish flame indicates a proper gasoline mixture, while a yellow flame shows the mixture to be too rich.

Great strides have been made in the use of this so called "heat-resisting" glass as insulators on high tension electric lines. They are made of different colored glass, as some lines require various types of insulators for different phase currents, and of different sizes and shapes according to voltage strength of the current. Claims for glass insulators are made as follows:

1. — Less expense in manufacturing than in porcelain.

2. — Shorter period of manufacture.

3. — Translucency.

4. — Withstands the temperature changes incident to day and night and seasonal service — passes the test from freezing water to boiling water through many cycles.