Can I re-blue case colored steel?

[Big Paulie]

Dear Guys,

  I have an old, relatively worthless, firearm with lots of rust on it.  Part of the gun is regular iron, but part (the receiver) was originally in case colors (which I assume is called case metal?).   At any rate, there are no case colors left, and it has large rust areas too.  As a fun project, I am going to take the whole thing apart, clean it up, remove all rust, and re-blue it.  (Since it is a small gun, I may use cold bluing on the parts.)

    Question is:  If I remove all rust and scaling from the case metal parts, can I re-blue these with cold bluing?  In other words, will case metal "take" bluing?

     If it won't take cold bluing, will it take a regular hot bluing job?

    Thanks for all replies.  (P.S.-don't worry, I am not ruining an antique.)

Best Regards, Big Paulie

[clodbuster]

Big Paulie  I nver had any luck trying to blue receivers that were originally case hardened.  They just turned a dull gray.  I'll be interested if anyone has any treatment that will put an attractive color on your old smoke pole.

[Hooker]

Big Paulie You may talk to one of the techs at Brownells. It seems to me that some of the older 94 Winchesters had actions that were hardend to the point that normal bluing processes would'nt touch them. but they would blue but I'm not sure how.

Pat

[gunnut69]

The M94 receivers you are speaking of won't blue due to composition,,  They contain an elevated level of silicon and were iron plated from the factory to get them to blue..  Since they were built when Winchester QC was in the pits I usually powder coat these...  Your receiver in most likely cast iron.. Case hardening is simply a process that forces enough carbon into the outer layers of the iron to allow it to harden..  The 'colors' are the result of a specific case hardening process.  They are a bit cantackerous to get to blue but usually can be colored.  I have my best luck with OxphoBlue applied to the receiver after it's been warmed, considerably.  If the case hardening is too hard the blueing won't take.,.  One needs to pickle the receiver a bit.  Use muratic acid, available at contruction supply centers, to soak the receiver just a bit.  The acid is used to etch concrete and clean masonry and is quite dangerous.  I usually use it mixed 50.50 with water(remember always add the acid to the water....  soak the receiver for a minute or so and rinse thoroughly in cold water..  baking soda can be used in solution to neuteralise the acid before the rinse.  Then try the blue again.  I had to soak twice on one particularly hard receiver but usually once is quite enough..  Be certain to stop the acid with a baking soda soak before completing the bluing process and wear adequate eye protection along with a rubber apron and gloves... Acid is not to be taken lightly!!  Remember with OxphoBlue the application process is repeated with a burnishing using steel wool (00) between applications.  More applications will usually darken the color, especially if steel wool is used between applications..  Sounds like an intersting project..good luck..let us know how it works out!

[Big Paulie]

Dear Gunnut.

Thanks for the thorough reply.  Dumb question, but is Oxphoblue a cold bluing, or a hot bluing process.

Thanks, Big Paulie.

[gunnut69]

there are no dumb questions just poor answers..  I should have noted - oxphoBlue is a cold bluing product sold thru Brownells.  It is used a lot in the gunsmith trade as it produces a very good blue that is quite durable.  Also there is no telltale smell and it blends well with existing bluing.  If the directions are followed including the burnishing steps the blue can become quite dense  and durable..  and it'll color steel thru a light coat of oil!!  That is a real benefit...