doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Shade tree case color restoration

Note in the ad the statement "Low Heat & Chemical". There is a process I have described here on this board on several occasions, taken directly from an Ithaca service manual, which they recommended for use on the Perazzis they once sold. These were I believe made from an alloy steel not suitable to regular case hardening but given a "Case Color" finish. The process consisted of heating to a temp hot enough to "Sizzle Water" (about 165°F) & then daubing &/or streaking with touch-up bluing on a Q-tip. This temp is less than boiling water & does absolutely no harm to the metal. The finish produced is actually rather well wearing & can be simply polished off if it doesn't suit. The question here is exactly what process did he use. If the colors were in fact produced my heating hot enough to produce "Temper" colors then they Do affect the original case. Yes Temper is the correct term. In heat treating the part is hardened to it's max hardness & then "Tempered (Drawn) back to desired hardness. In the old days, prior to a lot of sophisticated equipment this tempering was quite often done by "Color". The color is produced by oxidation at that temp, not by it's carburization, thus any "Temper" color produced has done so at the expense of hardness. Colors produced by "Spot" heating of a gun frame should in my opinion be avoided like the plague. The case of a case hardened/colored gun frame will normally be left at max hardness. Loss of color does not mean loss of hardness only that the oxidized layer has worn away.
Thus "Hardening" is the term which puts in the hardness & is done by heating a part above it's critical temp & quenching;
Tempering is a drawing of the max hardness back to a desired lower hardness & is done by re-heating a part to a predetermined temp which will obtain the desired hardness, but will always be less than that required for hardening.
Annealing is a process where the metal is heated to a high enough temp to remove all traces of the hardening & it will be allowed to cool slowly so no "Quenching" effect can occur to create a hardening effect.
There is no way one could, with a torch, heat an area hot enough to produce temper color without the case at that point being heated completely through, thus it will indeed affect the metallurgy of the case & it is being done non-uniformally. The original case was "Hardened" in a uniform manner, the random colors come from non-uniform oxidation, not from non-uniform hardening.

2-Piper has got it. No way would I consider buying a "recolored" gun like this unless it was going to be reharden by the proper methods. Bill

Thanks to all of you gentlemen, very much! I had heard many references here to the "torch master", but I never knew whom was being referenced. At the same time, in my quest for the perfect grouse-getter, Mr. Ed's ads caught my attention many times. Now I know...

Anyone wanting to know how to Colour Case Harden steel should read the following Forum:-

http://www.marlin-collectors.com/forum/viewtopic.php?f=21&t=3732

This runs to fifteen pages and details one mans experiments on CC Hardening. I have found no better source of information on this subject anywhere.(I've been looking for several decades).

He details the ratio's of the charcoal and bone charcoal, the methodology and the temperatures and equipment used. It's well worth a read even if you never intend to CC harden yourself. It also removes a lot of the mystique and bulls**t of CC Hardening that abounds on other boards.

It's worth viewing, if for nothing more than just the pictures.

Harry

Harry,

Hi, Michael Petrov here, The late Oscar Gaddy wrote several articles in Double Gun Journal about case coloring. I don't remember the issues they are in but I suspect that some here will know.

Harry,

Fascinating reading. Where is the film available from?

Pete

Articles by Dr Gaddy: 'The Double Gun Journal' Vol 7, Issue 4 Winter 1996 and Vol 8, Issue 1 Spring 1997
Also "Color Case Hardening by Mr. John Hackley" http://www.acgg.org/pub.html

Hello Michael,

I have both of Oscar Gaddy's articles, but like most people who do/did, CC Hardening he doesn't give much away. The first part is available as a free download from the www. The second part is available on purchasing the magazine in which the article appeared. Both parts are subject to copywrite and although one part is freely available, the second part isn't, unless you shell out a few bucks to buy the magazine it appeared in.

Harry

Hello Pete,

All I know is what is quoted in the CC Hardening article. The DVD or VHS tape is available from the Secretary of the Marlin Collectors Club. Price about $25.00. Sorry I haven't the address of this gent.

Harry

Thanks Harry, I found it. If any one is interested, Harvey Frakes MFCA 217-585-3454 between 6pm & 10pm CST

Pete