The Gateway Arch is clad entirely
in 304 stainless steel

304 Stainless Steel Clad Gateway Arch

304 Stainless steel

304 stainless steel (also known as A2 stainless steel) is the most common stainless steel available, it has high corrosion resistance when compared to regular steels, and has lower thermal and electrical conductivity when compared to similar metals. 304 Stainless is composed of iron, chromium, and nickel, with traces of carbon, manganese, silicone, phosphorus, and sulfur.

304 stainless steel can suffer from corrosion when exposed to chlorine and chlorine based chemicals. Undiluted bleach and other chlorine based cleaners should not be used to clean 304 stainless steel equipment.

More information about the physical properties of 304 stainless steel can be found at's webpage

316 Stainless Steel

316 stainless steel is the second-most common stainless steel available. It has similar physical and mechanical properties to 304 stainless steel and is made up of similar elements. The major difference between 316 and 304 stainless steels is the addition of molybdenum in 316 stainless steel. The addition of molybdenum increases the steel's corrosion resistance against chlorine and chlorine containing chemicals.

More information about the physical properties of 316 stainless steel can be found at's webpage


"Silicone rubber is the only class of space flight-qualified elastomeric seal material that functions across the expected temperature range."

Shuttle Launch Small

Silicone Rubber

Silicone rubber is an inorganic elastomer that is made up of silicon, carbon, hydrogen and oxygen. Silicone rubber is chemically stable, non-reactive, and resistant to temperatures from -130°F to 570°F. These properties make it an ideal choice as a gasketing material in food or beverage related industries. More information about the physical properties of silicone rubber can be found at's website


Viton is the brand name of a synthetic rubber produced by The Chemours Company, it is a fluoropolymer elastomer used in gaskets, O-rings, and other molded or extruded products. More information (including datasheets and chemical resistance guides) about Viton can be found at Chemours' Viton Page .


Buna, also known as buna-n or nitrile rubber, is a synthetic rubber copolymer consisting of acrylonitrile and butadiene. Buna is highly resilient and more resistant to oils and hydrocarbons than natural rubbers, but is less flexable. Buna is often used in labratory, cleaning, and examination gloves. More information about buna can be found at Wikipedia



PTFE or Polytetrafluoroethylene is a synthetic fluoropolymer that is more commonly know by it's brand name, Teflon. PTFE has an extremely low coefecient of friction, is highly hydrophobic, and generally non-reactive, making it ideal for use as a nonstick coating in the food and beverage industry. For more information on PTFE visit