doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Annealing before re-casing, is this BS ?

Color casehardening is a carburizing process wherein carbon is introduced to the outer layers of the steel in order to harden the skin of the part. In this process the carbon is pulled from the charcoal pack via heat and is trapped by the subsequent quench. Carbon must be present in order for steel to harden.

To properly "re-case" a part, the previous hardening process must be "undone" via the controlled annealing process. I used to
work in a very well known shop that specializes in casehardening and we NEVER re-cased a part w/o first annealing it.

Warpage in my experience relates more to the design of the action, trigger plate, etc. L.C. Smiths, Parker's and others rarely had warpage issues because the frames and other parts were thick where they needed to be and could usually be reassembled w/o hard fitting. Every Ithaca Flues that I have
re-cased required hard fitting. The tangs and trigger plates on the Flues always move because they are thin and just tend to warp due to the heat. It just takes a little time and experience to hard fit re-cased parts back to where they need to be for final assembly.

Dan May

I don't know if Wind River annealed or not, but I think the colors are nice.

I'll agree with you John, that a man with a proven track record has a better success ratio than others but even the best can have one turn out bad. They're probably just better at bangin' the thing back into shape.

They had to whacked into shape the first time they were done. Read crossedchisles article in SHOTGUN TECHNICANA about the PROTOCOL AT PURDEY'S. It was the finishers first task to stress relieve and true up all the metal that had warped in the hardening process. Now there's a guy with a good resume', and even he screwed up at times and it was his full time job. It's one thing to damage a part before the gun reaches the owner, you can make another, but what about your 1907 Fox? Are you going to be happy if he breaks the top tang and has to weld it?

I think it's a gamble with a SxS because of the critical geometries involved with the barrel fit, too much of a gamble for a vanity exercise.

Old Highwalls, Sharpes and slab sided lever actions? Have at it, not too much to mess up there. But my old SxS's will age gracefully.

Just curious, do the re-case color guys have you sign a waiver before they'll cook your action?

Just to set the record straight, Cyanide "Hardening" is not a chemical process but a carburizing process as is the charcoal method. It is used when a very thin case is satisfactory & operates by immersion of the part in molten Sodium Cyanide at temps on the order of 1450°-1650°F. The metal absorbs a thin carbon rich "Skin" which is hardened upon quenching with the colors formed by oxidation. One might say, "It is the same, but different" as Charcoal hardening. Cyanide hardening is I believe quicker & generally less expensive than "Pack Hardening" (Charcoal) but normally does not give as deep a case & colors which in the eyes of many are not as attractive.
Ref; "Machinery's Handbook" (not a direct quote)

Doug Mann,
Thanks for that info. I've been hesitating to color the gun because 2 folks here have dealt with post CCH warpage. Now I'm sure I'll blue it.


Edit: My question to Classic was regarding a previously blued reciever...not re-casing.

Miller,

Thanks for that last post. It should also be remembered that for some guns, it is the correct method. Cyanide case colors have their own appeal.

Pete

It should also be noted that parts can be recolored without rehardening. The temperature range wherin oxide colors form is well below the kind of temperatures likely to warp metal. Dr. OG recommended doing this. Note that most of the colors in CC are within the range of iron oxide colors, but some depend on other stuff such as is found in the bone charcoal. Masters of the process can control to a significant extent the pattern (sttripes/spots/mottled) and the predonimance of color (mostly blue/mostly brown/a dash of green/almost grey/etc). Usually, one wishes for the master to recreate what was originally on the gun.

I would reccomend annealing before CC'ing. And no, it does not do the same thing when you heat the action up in the CC'ing process.

I remember reading somewhere that if metal washers and/or various bits and pieces of metal are wired to portions of the item to be color case hardened (bone and charcoal method)that the case coloring patterns can be controlled and duplicated. Is anyone familiar with this? I think that this is practiced in the U.K.

Oscar would not recase without annealing first. The hundreds of actions he did had no distortion problems and did not crack later.
bill