Summary for gun bluing chemicals Discussion
nitrate for bluing guns comes up because the original questioner asked where to buy “nitrate acid” for bluing a gun. Jeff Cochran replied that there is no chemical called nitrate acid and that nitric acid is not part of gun bluing, though nitrate compounds can be part of some hot-bluing formulas; he also noted that many store-bought kits use selenium dioxide for cold bluing, which is more of a coating than true bluing and may not work on stainless steel. Ed Kay added that hot bluing uses a solution at about 295 degrees and requires special tanks and caution. George Schwoboda suggested the needed chemical may be part of a rust-bluing formula, which is useful for double shotguns with soldered barrels because it will not attack solder and needs little equipment for occasional home use.
Q. I am looking for some nitrate acid for bluing a gun, can you help me find a place I can buy some.
Thank You,
R.B. Lawson
– Novenger, Missouri
A. I don’t know about the nitrate acid, (maybe that’s what I need) but you can buy a kit for reblueing your gun at most sporting good stores.
However I haven’t found one that will blue stainless steel, which happens to be my problem. (Is that what the nitrate acid is for?)
P.S. The main chemical in the gun blue I have purchased is SELENIUM DIOXIDE.
Jeff Cochran
– Hermiston, Oregon
A. Hi. There is no chemical called nitrate acid, and nitric acid is not part of the gun bluing process. But some nitrate compounds can be one part of the formula for “hot bluing”. You can find formulas in the Metal Finishing Guidebook.
Selenium compounds are used for “cold bluing”, sometimes called “cold blackening”, and they are more of a coating of selenium than a process that actually blues steel. You can read about the differences in our FAQ: Black Oxide and Cold Blackening.
Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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A. I use a caustic soda ⇦liquid caustic soda in bulk on
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solution, but it is for hot bluing at 295 degrees and takes special tanks, etc. and a lot of caution.
Good luck.
Ed Kay
– St. Louis, Missouri
A. I believe the acid you are looking for is part of one of the many formulae for “rust” bluing. Rust bluing is used on double shotguns with soldered barrels as it will not attack the solder as does hot bluing. It requires little equipment, making it handy for the occasional home blue job.
Good luck.
George Schwoboda
– Richfield, Minnesota


