Flexible graphite seals are touted as the best new seal and gasket product in the last 10 years, according to two distributors selling the product in sheets, packing and cut seals. The products are very-high-heat resistant and, in static applications, can outlast the parts they are joining.

According to Dave Steadman, owner of American Seal & Packing Co. of Fountain Valley, Calif., the quality of foreign bulk flexible graphite rose in the last few years, while prices for those goods came down.

"The quality from overseas was poor for a long time," Steadman said. "But recently, the people making the products met with a lot of people here and it's gotten a lot better. They are ISO 9000 overseas now."

Domestic prices from companies like Union Carbide have held steady, Steadman said. He thinks domestic graphite is still higher quality, but import prices dropped dramatically, setting up the classic price vs. quality scenario for customers.

"The flexible graphite seal will outlast the valve it's used on in most cases, so product life is not an issue," Steadman said. "Most of the seal and gasket changes result from scheduled maintenance, not due to a failure."

That being the case, it is likely a customer will choose the foreign product, he said.

"When you use them in the absence of oxygen, they seal up to 5000°F," Steadman said.

Flexible graphite was introduced in the '80's as a substitute for asbestos but was prohibitively expensive, said Jerry Whitlock, also known as "The Seal Man™." Whitlock, owner of EPM, Inc., in Stockbridge, Ga., concurs with Steadman about prices and material performance. Prices are coming down due to universal acceptance of the material and a plethora of Asian suppliers, he said.

"I receive solicitations nearly every day from Chinese flexible graphite manufacturers wanting to sell to EPM," he said. "Low labor costs and low-tech manufacturing methods ... are driving the price down."

Graphite has low-torque bolting requirements and has a tendency to fill voids and other imperfections on the flange face, he said. Unsupported flexible sheet is fragile, however. A stainless steel foil laminate or Mylar™ inserts are used to strengthen sheets.

Seal distributors find the most uses for flexible graphite in steam power generation and other steam systems, process industries, boiler rooms, and other pressure vessel gasketing applications, Whitlock said.

Automotive applications appear to be an up-and-coming sales area for flexible graphite gaskets, he said.

"We have successfully used it in high-performance internal combustion engines — like racing cars," Whitlock added.