doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Case Coloring

You don't say whether or not the beer had been "processed" first...

No matter. Urine good company.

And you've given ed good a new idea!

And was it ale, dark, or light ? More research is needed me thinks....

Interesting thread,,,, bottle or can ?

"Filtered" indicateds "processed," IMO. Further, IMO, I suspect there is at least one true incident of a CC'er "peeing in the quench water." IMO, this was his subtle hint as to what he thought of you request for disclosure of his secret (and successful) process. But, I could be wrong.

DDA

I believe it is a pretty well established fact that at least one Southern Armory during the "War of Northern Aggression" had people save their Urine & bring it in, from which the procured the Saltpeter (Potassium Nitrate) they need for making powder.
I have also heard of the practice of mixing some Saltpeter in the quench water for CCHing for the purpose of releasing Oxygen to produce better colors.
I am not enough of a chemist to know for certain but perhaps peeing in the tank would produce a similar affect, but I'll leave it to others to find out.

Still wondering how cyanide works to color steel. Seems a common practice on the Continent. What's the chemical process and is heat involved?
Don't worry, I wasn't going to try this at home.........

From my internet notes...

"Some color case hardening is done in the Vat method, Stevens and others used this method. It is called Cyanide. Cyanide is a salt that when heated up to about 1600 degrees or so anneals what ever is put into it and then hardenens it. It goes from the cyanide bath to a water quench. The Stevens got there ripple effect from a chain that was used to lower the parts into the bath and pull them up, supposedly the cog wheel the chain ran in helped make the pattern as it stopped momentarily at each cog. There is a company in Wyoming that uses this method with nice results. Not something you can do at home."

"Signal Mountain Gun Works uses an abbreviated potassium-cyanide based process for color case hardening. Browning/Winchester uses the company for their firearms since the receivers are already sufficiently hard (SAE 4140 steel heat-treated to a hardness of RC 38-42) and case colors are the main goal. Since case colors are the main objective (not a thick hardened case) the potassium-cyanide bath is heated to 1215 to 1225 degrees and the parts are left in only 5 to 10 minutes. I understand that a much thicker case can be achieved using the same process, but the temperature is increased to the range of 1400 to 1650 degrees and the parts are �soaked� for at least an hour, usually longer."

So to sum up they use heat and Potassium-Cyanide salts. I am sure the fumes are vented most likely after some type of conversion to harmless state by a catalytic conversion process and all workers around must wear breathing hoods and chemical barrier type clothing. Plus I suspect the EPA might become your best neighbor and constant companion. Even skilled amateur should let the pros handle this one.

Thank you KY Jon. I wondered how it was done. It seem from your description that the potassium cyanide at the higher temperatures would impart some surface hardening to the metal as well.
Other than a difference in the color patterns, are there any functional differences in cyanide salt and bone charcoal processed metal?

Have been searching without success to confirm:
1. Charles Jerred was briefly blinded by an accident using cyanide for case coloring at Hunter Arms. The Fulton guns were colored with cyanide rather than bone charcoal. Bro. Tom probably knows.
2. An English gunmaker was found dead in the basement of his shop, presumable from the fulminate of mercury he was using to make percussion caps or primers. William Eley?
http://newsgroups.derkeiler.com/Archive/Rec/rec.pyrotechnics/2005-12/msg00095.html

A few terms that need to be understood. In heat treating parts which are to be hardened, are hardened to their maximum attainable hardness by being heated above their critical temp & quenching to cool them suddenly, the actual quenching medium depending upon the actual alloy. If this max hardness is not what is desired (Usually isn't) then they are tempered to bring them down to the desired hardness range. The higher the tempering temperature the softer the result. Charcoal & Cyanide are essentially two carbon bearing substances which when the part is heated above that critical temp the carbon is absorbed into its surface. The longer it Soaks at that temp in the presence of the carbon the deeper it penetrates. However the deeper it goes the longer it takes to go further so there is a more or less practical limit to the depths achievable. An alloy steel such as 4140 is seldom case hardened or colored. These steels are most often simply heat treated. They are quite often used for parts requiring high strength & the temps for coloring cannot be higher than the tempering temperature to which they were heat treated. I worked a few tons of 4140, 4340 etc in my career as a machinist & seldom died we temper it higher than around 900�F. Coloring it by cyaniding would be a specialized process not used too often in my opinion. Thos last two digits in 4140 denote approx 40 points carbon, case hardening is normally done on steel with a max of about 20 points carbon.

I don't believe cyanide case color hardening was or is all that rare. I think it was a cost effective manufacturing process and not reserved for higher end guns and rifles. Chances are millions of H&R Toppers had their receivers finished that way. I believe it's the current 'normal' receiver finish at Shiloh Sharps and pack hardening is an extra cost option.

I also believe alloys that can through harden, such as 4140, are regularly case colored, because I suspect that's what the market wants. I think many of us have seen tons of case colored Rugers, or imported single action revolvers and lever rifles with the look. I suspect the larger case coloring houses are called on to color 4140 regularly.