Real Deal Case Colors

[ed good]

bruce: your comments regarding the differences in how frames and trigger plates are processed is interesting and new to me. perhaps all parts are hardened to the same spec, but then tempered to different specs, depending on the amount of elasticity desired?

i am no expert either, but do find the subject of factory shotgun receiver hardening and coloring to be fascinating.

[edgarspencer]

No, Ed, Temperatures for any heat treatment are specific to the metallurgy and the end result you want to achieve, not the manufacturer.
Those temps I referenced are typical for most Ni-Cr-Mo alloys with Carbon in the .20% to .30% range

[ed good]

another thought on the subject:

early shotgun receivers were machined from solid blocks or billets of rolled steel.

floor plates, trigger plates and lock plates were no doubt made from sheets of much thinner bar stock.

could it be that the billets of rolled steel were of a different alloy than the thinner bar stock? if so, that could account for the difference in how the case colors developed and appeared on the different parts of the gun?

[B. Dudley]

Dean,

I Don't want to drift off topic too much, but the picture you posted of your nieces vase is nice. I believe that this piece was Raku fired. This is a process where the clazed piece is fired to temp. and then removed at temp and then placed in a trash can with straw, hay, papers and other organtic materials. It creates a wonderful effect.

There is also an old Native american method called pit firing which is just the bare unglazed clay that is buried in a pit with a fire in other organic mateirals. And left to smolder for days. That process is very unpredictable, but can sometimes yield some great colors.

I was a Ceramic arts major in college. So it is a subject that I am familar with.

[Bruce Day]

EDG, if you will look in The Parker Story, the key reference books for Parker enthusiasts, you will see on p. 427 photos of frame forgings and explanation of the hammer forging process.

A person can learn a lot about Parkers, restorations including correct charcoal color case hardening, and what is correct in Parkers, by study of TPS, which was written by experts on the Parker gun and the Charles Parker Company.

Bruce Day, no expert but I've read a lot, learned a lot from experts and been fortunate to have been around a lot of nice Parkers.

[Craig Larter]

I noticed on the PGCA 2012 raffle gun (10 ga hammer) the side plates retain much more CC than the action. Syracuse LC Smith's also age the same way, more color on the side plates versus the action. It must be the difference in steel and or the CC process. I have been told that the forging process modifies the grain of the metal resulting in some areas retaining cc better than others and some frames holding cc better than others. here is a Smith example of what I am talking about.

[AmarilloMike]

Same with the Syracuse Lefevers. The sidelocks/sideplates hold the case color much much better than the the frame does.

Best,

Mike

[ed good]

mike: wonder why that is? ed

[Bill Murphy]

Mike,

[Parker Bachelder (Brad's Profile)]

It is imposible to quickly explain all of the variables that effect color case hardening. Contrary to conjecture and rumor the process is controlable and predictable.

two constants in the process are: type of metal, machineing reliefs.
The type of metal cast, forged, or rolled dteel, absorb carbon at different rates. Rolled steel, due to molecular density absorbs more carbon than cast steel. Sideplates and triggerplates are usually rolled steel accounting for deeper, longer lasting colors. Recievers cast or forged, absorb less carbon or color affecting durability.
Machineing translates to repeatable patterns in like parts. In the heat up phase thick areas remain cooler than thin areas. at quench thick areas cool slower that thin areas. Two prime examples of this in Parkers are the center band of color on triggerplates at the point of machineing for the cocking slide. The centers of the water table flats at the hammer spring pockets.
Parker forearm irons form a distinctive pattern at the "T", we refer to this pattern as "antlers". This is created by drawback or outside cooling at quench.
Pin holes, screw holes and edges drawback or turn straw or grey due to rapid cooling.
Color ranges, contrast, machineing patterns and patina, are all controlled with process variations in packing materials, tempature,surface preperation and exposure to oxygen. A careful educated study of original specimens is the most important factor in creating a process formula. Every manufacturer used the same basic process. The secret ingredents were not magical or chemical. The variations were in process crontrols and specific steel types.
We utilize over 20 different process formulas to yiels specific colors and patterns by brand and era.

Brad