Birchwood Casey’s automated Tru-Temp finishing system uses a two-stage oxidation process to form a black magnetite finish on all iron and non-stainless steel parts. The process is said to operate effectively at a temperature 100oF lower than other black oxide processes that require a temperature of 290oF. The result is a protective black finish that is 0.000020″ thick with a satin black appearance.
The blackening reaction takes 6 to 10 minutes. As a result, the entire process is shorter and the work flows faster, resulting in lower labor costs, the company says. Labor is the largest single cost factor of any blackening system, so overall finishing costs are reduced.
Solution monitoring is performed in less than a half hour using a color change test that indicates proper concentration level.
Because the process contains no EPA-regulated chemicals, there is no need for waste treatment equipment—a pH adjustment prior to discharge in sewer systems is all that is required.