The Story Of O-rings

As usual, I greatly enjoyed the latest issue of your magazine, and I am delighted that it will now be published four times a year. I particularly enjoyed the articles on Glenn Curtiss and Niels Christensen.

Regarding the latter (“Ring Master,” by George Wise, Spring/Summer 1991), you emphasized O-rings’ physical design but not the materials from which they are made. If Christensen had invented the O-ring much earlier than he did, when only natural rubber was available, its practical applications would have been severely limited, since many of the fluids to be sealed would have rapidly caused the rubber to deteriorate. Fortunately, Du Pont and others have come up over the years with a succession of O-ring materials to handle almost any fluid, even at elevated and subfreezing temperatures. These include neoprene, Viton, buna-N, ethylene propylene monomer, silicone rubber, and Kalrez perfluoro-elastomer. For static applications O-rings of hollow all-metal construction have been used, as have composite constructions.

Malcolm G. Murray, Jr.
Murray & Garig Tool Works
Baytown, Tex.