A. Zinc plated hardware is not really satisfactory for outdoor or buried use, John. Ted Mooney, P.E. Striving to live Aloha finishing - Pine Beach, New Jersey March 6, 2008. A. John, I once installed an outdoor lamp post with 1/4-20 zinc plated threaded rod, only to have anchor rods 3 feet in ground & concrete corrode out in 1 year. …