Aluminum material with a copper content level above a level of 0.4% is susceptible to corrosion. Rose uses AL Si 12 alloy in its cast aluminum Aluform housings. The term “Copper Free” is used to describe aluminum alloys which contain less than 0.4% copper. The copper content in Rose’s enclosures is .1% for Die Castings and .05% for Chill Castings and Sand Castings. It is the reduction in the copper content which increases the natural corrosion resistant properties of aluminum. Copper Free aluminum is particularly resistant to salt atmospheres, sulfur gases, and ammonium nitrate.