Gun blue composition

Birchwood Casey seem to have changed the compositon of their Super Blue Liquid Gun Blue. I have recently bought the bottled version and the paste version. Both are labelled as containing Selenium dioxide. The paste version works really nicely on steel (in fact I think the coverage is less patchy) but will not touch brass (as indeed the label now clearly states).

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10 years ago (I still got the bottle to prove it) the liquid version contained "nitric, phosphoric and selenious acid" and blackened brass really nicely. Is there a reason why the company changed the composition?

Furthermore, does anyone have experience with the Brass Black Metal Touch up (15225 -BB2)? Is it any good at turning brass black? Is it similar to Gravoxide?


Reply to
Michael Koblic
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Michael, You are speaking about a cold blueing compound which is acidic. Proper gun blueing compond is a base(salt) and it is mixed with water and heated to aproximately 295F. The amount of salt is conntrolled by observing the boiling point of the solution. Steve

Reply to
Steve Lusardi

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