Campfire color case

[James Wilson Everett]

Nordnecker,

I try to catch the color I call peacock when coloring my iron parts, just because it is pretty, sort of a purple/blue/brown color.  But, possum ear blue is a lot more descriptive, next time a possum pays a visit, I'll check out the ears.  I have reformed my vocabulary - peacock is out and possum ear is in.  Thank for the "colorful" word.

Jim

[D. Taylor Sapergia]

Jerry Huddleston (may his tribe increase) explained the variation in colours well, when he talked about wrapping the part with a random wrap of iron wire prior to heat treating.  Perhaps that thread can be resurrected, or perhaps Jerry might see this and chime in with another great lesson.

[jerrywh]

If you want more blues in the colors add a small amount of potassium nitrate to the water.  It is the oxygen and steam in the water that creates the colors not the carbon used in the pack but more bone charcoal will make more grays.  Wrapping the parts with wire or placing another piece of iron or steel close to the part will enhance the colors because it traps the steam close to the part while it cools.
  Notice this. If you heat blue a piece of steel exposed to the atmosphere it will turn blue but if you paint part of the surface with a deoxidizer or a flux such as borax and alcohol that part will not turn blue but will remain bright.
  Beautiful colors can be obtained without hardening a part. Any temp. over approx. 650° will give colors.
 Colors are more durable if the part is hardened at 1450° or above.  As the quenching temperature goes over 1550 the colors begin to disappear. At around 1700° and up there will not be any colors to speak of. Also too high of a quenching temp will give the metal a grainy look.
 I personally care less about colors than I do about hardness. Hardness preserves any engraving and make the lock action more proficient and durable. 
 Infra red pryrometers are cheap and work well for this type of work.

[KNeilson]

Great thread, I have had an interest for a while to use this process on more than just gun parts. Due to what Ive read, I have been reluctant to try to experiment with charcoal production and secret mixes and amounts etc. The exorbident mailing costs for me to get some of the components is proof of this... The question I have for the more experienced is reccomending some good reference material for me on this process..  thx..Kerry
  As a footnote, I was told by a metal artist once to try quencing metal in an aireated bath with a couple drops of vegetable oil added. He managed to produce decent colors in his work but it was not very durable and had to be laquered

[Jerry V Lape]

The process of producing case colors is extremely important to those with  interest in expensive shotguns.  The process is very much as the campfire one discussed here but there are company secrets about the things added to get the same colors over the company's total production.  For example, Parker guns and L.C. Smith gun colors are  easily separated by their differences in colors.  Colors redone by gunsmiths other than the manufacturers are quickly detected.  Turnbull will case color and has pretty much cracked the code on proprietary colors.  Parkers made late  in the Remington years of production were colored with a Cyanide process which doesn't sound like something for small shops or hobby builders to play with.  The colors are only a molecule or two thick and easily worn away by handling.  Shotgun makers coat the colors with a lacquer to protect the colors from hand wear.  Color life can be extended by periodically re lacquering.  Items like lock plates are susceptible to warping and need to be put into a supporting metal fixtures to hold them straight. Fixtures also play a role in the coloring patterns.   There are risks to the parts.  Two identical high end shotguns in perfect condition can vary in value by several thousand dollars based on the degree of "original" case colors remaining. 

[andy49]

I just use a propane torch and heat the metal to my desired color and quench in 30W motor oil, wax it and you are done. You can see an example of the color on this pistol display rack

[Jerry V Lape]

Andy, the torch method is not the best process.  First if the piece is case hardened the torch method will likely ruin that and weaken the metal.  Second, the colors are very recognizable and often used to deceive the unaware into thinking they are buying a good finish which it clearly is not.  In shotgun circles it might even get you publicly verbally lynched for ruining otherwise useful guns.  The torch also does not case harden the metal to provide the same level of wear and rust resistance which real case hardening processes provide. 

[jerrywh]

KNeilson
  Believe me when I tell you that I have done a lot of this for at least 30 years. You don't need any exotic mixtures . all you need is good clean wood charcoal. Grind it to about the consistancy of a matchhead or 1/8" size and smaller. What the guy said about warping lock plates is true. It is a very good idea to brace the lock plate some how to prevent warping. I usually bolt mine to a thick piece of steel with some spacers betwen the block and the lockplate.  Do not put any type of oil in the water or it will not come out with good colors. Clean fresh water at room temperature works best and you do not need to blow air into the water. ice cold water is dangerous and can cause cracking.  a piece of pipe with a cap on one end makes a good container. Just set a lid on top .  A piece of sheet metal will do for a lid. You can get a pyrometer for about 50.00 or less to measure temp. Infra red type work well. soak in the heat at 1450° to 1550° fo an hour to an hour and a half. Quench at that temp. do not let air get to the parts before you quench and watch out for your hair and eyes when you quench. I wear a face shield and wet my hair.
 When you done dry the pieces off and reheat them to about 350° in the kitchen oven for an hour. that will take most of the stree out of them and enhance the colors some.Then oil them.
  Both of these two locks are case hardened. On the first one I added some potassium nitrate in the water to make a lot of blue. The next one was case hardened and then brought back bright to be historically correct.


http://jwh-flintlocks.net/lockface-2012.jpg
http://jwh-flintlocks.net/jaegerlock-super1-small.jpg
one more   http://jwh-flintlocks.net/casehardenedlock4.jpg

[oldfox]

Wow!  Those are elegant looking locks!  Nice work..

[razor62]

Jerry, those colors are superb! Do you use an oven for this or are you a campfire guy too?
I'm wondering if a campfire heat source is capable of yielding consistent results?
Perhaps a woodstove would prove useful for this.

[jerrywh]

  I now use a electric furnace that I built. Basically it is a electric kiln with a front opening door.  I use this now because I do a lot of gold work on guns and with gold I need a real close temp. control. I put a type k thermocouple right on the parts container. Strangely gold will melt at about 1575° when packed in charcoal. Gold is a weird metal. I learned that the hard way. You can ruin a months work in a short time.
   Years ago I used a wood stove and then a crucible furnace. A wood stove works well with a large fire. A large wood fire would work just as well but I would not use a forced air draft like a blower because the fire will get too hot.  A plain wood fire with a natural draft works great because it seems to burn at about 1500° F. Lots of good red coals is what you need. the heat needs to be retained for at least an hour. I used to harden frizzens in a woodstove back in 1970. It worked real well.
  Dave Race knows a lot about this also. Maybe he will chime in. He teaches classes on this.

[razor62]

Jerry, I can't thank you enough. You've got no idea how valuable your experience is to me with regard to this process. I'm sure that I'm not the only one who appreciates your taking the time to explain how you managed to obtain these colors.
Another question if I may... You mention wood charcoal but nothing about bone ,leather of any other types of charcoal. Are you saying that you were able to get results like those pictured with wood charcoal only?

Thanks again,

Kevin

[jerrywh]

 Yes. I have obtained excellent colors with nothing but wood charcoal. However I do mix it with bone charcoal on some occasions. It doesn't seem to make that much difference though. The charcoal has to be clean. Well burned out and with no oil or other contaminates.  The kind of wood used for the charcoal makes no difference.  I have used raw bone meal but no colors will be obtained with it. It stinks also.  Bone charcoal is expensive. Brownels has it but it is not neccessary. Brownels also has wood charcoal. I buy it because I know it is clean. Leather scraps are lousy for color hardening.  Leather will work for plain case hardening of a frizzen or something like that.

[J.D.]

Wow, Jerry, I am always blown away by your work.

Those locks are beautiful.

[razor62]

Thanks again Jerry. I just finished welding up a crucible and a set of forks to handle it with. Ground up some hardwood charcoal. Ordered a pyrometer with a temperature range up to 1625 F.
If all goes well I'll be running some experiments next weekend.
Thanks to JPK as well for staring this thread and inspiring me. Thanks to everyone else for their input.  I'm psyched!!! 

[Spatrick30]

Although this is an old topic I recently had satisfactory results with an attempt to case harden the steel on my rifle. I figured the addition may aid someone else looking to do similar.  The pics show the results of a hardwood fire, crushed hardwood charcoal, a 5.56 ammo can crucible, and 30 gal trash can.  I used 1 bottle of stump killer (potassium nitrate) in the quench of tap / well water.  I braced the parts with 3/16 steel found on most any hardware store to limit warping.  I wrapped the parts with degreased tie wire while trapping some larger parts of charcoal between.

My objective was to create a hard surface with interesting coloring, not necessarily a striking color case job.  The bad... My tang warped due to not being screwed down firmly enough; I'm now fitting a new tang to an inlet and finished stock.  Lesson learned, don't attempt to straighten a hard part.  I haven't tried firing the lock yet and hope the cock doesn't shatter.