Weathering steel is known for staining adjacent surfaces with iron oxide as the material continues to age. Our preweathering process reduces and often eliminates staining of surrounding surfaces.
We work with the mill source to ensure that the raw steel ingot is derived from specific alloying components, base raw material is cast to exacting specifications. Next, we work with a rolling mill that understands the finesse required when working with bare weathering steel. They are careful to avoid scratching. If you don’t influence the base metal sources they will treat the material like basic steel: it will be heavily oiled, scratched, and scarred. These contaminants will show themselves in the final product as streaks, rings, and discolorations in the finished surface.
We inspect each and every plate surface. Each surface is cleaned and prepared to eliminate oxides, greases, and oils. If this step is not carefully followed the finish will not hold up. Once properly prepared, we force the surface to an initial ferric oxide. This finish is slightly orange in color and is characterized by a crusty texture. An orange patina is not a permanent patina. A finish with yellow and orange will rub off, it will continue to darken, bleed, and stain adjoining surfaces. Orange is soluble. Within our facility, we allow this orange-toned oxide to grow to a point, and then remove most of it from the surface. The surface is then exposed to a proprietary solution and specific atmospheric conditions to develop a hydrated oxide form of ferrous oxide or ferrous hydroxide. This is insoluble. We cultivate the growth of the hydrated oxide form until it reaches a certain point. Then we arrest it with another proprietary solution that inhibits and slows oxidation to a standstill. The material is in its final stage of development.