Hot-Rolled Cor-Ten Steel numbers and letters are water-jet cut from raw cor-ten steel in the various thicknesses mentioned in the table above.
The natural raw finish is purposefully uncoated so that it will rust.
Depending on the steel stock used at the time of cutting, the initial surface will appear as a hue between a steel blue-grey and silver. Also, there may already be some rust on the pieces.
The cut edges of the raw steel will be a fresh silver tone due to the water-jet cutting. The returns are bead blasted
The photos above show the progression of rusting over an eight month period in moist Seattle conditions.
Note: Our pieces are cut from Cor-TenTM flat-sheet steel (77% recycled). Until the sealing coat of rust has completely covered its surface, this material will "bleed" onto the installation surface of exterior locations.