Du-Lite is still in business. They sell the black oxide that is used in the hot bluing process. The finish you get depends on the prep work. If you have a mirror-like finish to the steel, then you get a very shiny blued finish when done. If you want a parkerized look, you can bead blast the steel and then run it through the bluing process. It will look virtually the same as a parked finish, the only difference is that a hot process was used to color. I have done several guns with Du-Lite chemicals and done some each way.
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