Bruce Vernyi's Page 6, March 11 article, ``Plastics challenging metals under the hood,'' made a good point [though] missed a bigger one. Steelmakers may be boasting, but the annual consumption of sheet molding compound in automotive exteriors by 1998 will exceed 300 million pounds, up over 200 percent from 1990. Ford, GM and Chrysler all show sizable conversions from metal to SMC. Roofs, hoods, spoilers, bumpers, doors and other parts show metal replacement growth. Then, glass, nylon and poly-phenylene sulfide were praised for their outstanding growth in under-the-hood applications. I applaud these examples of heat and chemical resistance generating solid market growth, but please don't forget the real winner for the past five years. Bulk molding compound under the hood - both unsaturated polyester-based and vinyl ester-based - has outgrown all the engineered thermoplastics combined, starting with headlamp housings, where BMC has not only replaced metal, but glass, and the more expensive engineered thermoplastics.
If we take a couple of new applications like valve covers, timing change covers and oil pans where heat and chemical resistance are needed, BMC will be the fastest-growing under-the-hood material well into the 21st century.
The recyclability, long-term creep resistance, chemical resistance, and price per cubic inch have positioned BMC as an outstanding metal replacement alternative.
Larry E. Nunnery Jr.
Bulk Molding Compounds Inc.
St. Charles, Ill.