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

"Michael Koblic" wrote in message
...
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).

http://www.birchwoodcasey.com/sport/...=1&subcat=5#11

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?

Thanks,

--
Michael Koblic,
Campbell River, BC