Saltwater covers close to 70 percent of the earth’s surface. We love it, but we admit that it is vicious. Brine attacks all metal fastenings and fittings, including iron, steel, copper, brass, and even bronze. It is thus tempting to worship a relatively young alloy, stainless steel, that seemingly ever-bright, weatherproof, defense against rust and decay. Stainless steel, however, isn’t stainless.