If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed.
Bluing is a passivation process in which steel is partially protected against rust, and is named after the blue-black appearance of the resulting protective finish. True gun bluing is an electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite (Fe3O4), the black oxide of iron. Black oxide provides minimal protection against corrosion, unless also treated with a water-displacing oil to reduce wetting and galvanic action. A distinction can be made between traditional bluing and some other more modern black oxide coatings, although bluing is a subset of black oxide coatings.
In comparison, rust, the red oxide of iron (Fe2O3), undergoes an extremely large volume change upon hydration; as a result, the oxide easily flakes off causing the typical reddish rusting away of iron. "Cold", "Hot", "Rust Blue" and "Fume Blue" are oxidizing processes simply referred to as bluing.
"Cold" bluing is generally a selenium dioxide based compound that colors steel black, or more often a very dark gray. It is a difficult product to apply evenly, offers minimal protection and is generally best used for small fast repair jobs and touch-ups.
FFS Toby when did you get you BSc? If those were my instructions for bluing it would never happen! I think it was hot water with chemicals in a tank long enough to take the barrel and some heat underneath and keep watching. Oil it when finished
Welcome to NZ Hunting and Shooting Forums! We see you're new here, or arn't logged in. Create an account, and Login for full access including our FREE BUY and SELL section Register NOW!!
Bookmarks