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Fit & Finish Fit and Finish = the difference in "good art" and "fine art." Join in, as we discuss the fine art of finish and embellishment. |
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#1
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Color Case Hardening
Hi Everyone,
Just for the fun of it I would like to offer my two cents worth on how to color case harden bolsters, gaurds, pommels, and such the old fashoned way. You must use low carbon steel. 1018 works really well. The parts also need to be finished because you will only be able to lighty buff them when done. You will need a piece of iron pipe (not galvanized) big enough to hold the parts without touching the sides. Threaded on both ends with caps. Bone meal from a garden store. Strips of leather. Some sort of salty fluid (old formulas call for urine, different salts get different colors). Soak the THIN leather strips in your favorite salty solution and wrap them tightly around the part(s) and let them dry enough to stay in place. Seal one end of the pipe tightly with one of the caps. Tightly pack the part in the pipe leather and all with the bone meal. The part must be compleatly surrounded by bone meal and not touching the sides of the pipe and no air spaces. So get a big enough pipe. When you have everything packed tight fill the other cap with bone meal and screw it on by hand only. Not too tight it will need to vent moisture and you will need to open it hot. Okay now fire up the forge, grill, campfire, etc. Put the pipe in the fire, heat it to a cherry red and let it cook until all the bone meal and leather is consumed ( I did say you will have to experiment didn't I). This usually takes a half hour or so depending on your version of cherry red. When it has cooked enough you unscrew the cap and dump the whole works in a bucket of water to cool. The part(s) should be very hard on the surface with mottled colors. Results depend on a lot of variables and getting the wonderful colors of the 19th century arms is an art form. Be sure to try it with some scrap first. This is sutable only for low carbon steels (not knife steels). Tom Last edited by T L Smith; 01-27-2004 at 11:35 PM. |
#2
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Thanks, Tom. That's one of the best descriptions of color case hardening that I've heard. I have known the basics for a while, but the particulars of how to actually perform the task eluded me. Fer'instance -- I couldn't figure out how to enclose the part with the leather and bone meal and still be able to get it out before it cooled off.
Nice post. I'm adding it to my favorites. |
#3
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I can't begin to say how much I appreciate information like this.
All of you guys that present information like this and share it with "brothers" as it were...do more than just pass on a "secret" You perform the greatest of services by handing down knowledge and preserving our heritages. More now than ever, unselfish acts are our saving grace...thanks for sharing... ....I appreciate it __________________ Hank |
#4
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You are welcome,
I am glad the information was of some use. Tom |
#5
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great description of the process, tom. would the remaining salts in moistened chrome-tanned leather be sufficient, or do i need to boost the concentration?
. thanx a lot! __________________ wayne things get better with age ... i'm approaching magnificent |
#6
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I wonder what the results would be, if you substituted commercial Ammonia for the salty solution?
I have often thought that Ammonia was the chemical that helped in tempering(urine), not the salt content. :confused: __________________ Mike |
#7
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Most of the old formulas are lost so all you can do is experiment. Urine has to "age" a bit to produce ammonia as it is produced by bacteria.
I would not want to get too much ammonia in there, can you say PIPE BOMB I think we would want to minimize the nitrates But seriously the case hardening comes frome the carbon in the bone meal. The color comes from the metalic salts in the leather, salt solution, and bone; ie the chromium, potassium, arsenic, silver, sodium, calcium etc. This process is meant for decoration only, on mild steels. Most if not all knife steels will not case harden. Last edited by T L Smith; 01-28-2004 at 05:21 PM. |
#8
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Quote:
Exactly my point. It certainly wasn't new stuff everytime they wanted to temper blades, there weren't that many red headed virgins in the world. So the collected urine was was just added to the collective container, I guess.:confused: __________________ Mike |
#9
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Mike,
I don't understand what tempering of blades has to do with color case hardening. The two things are unrelated. All I know is if you put any form of ammonia in an iron pipe and heat it red hot you are likely to blow yourself up. All jokes aside in the future I will think twice before I post anything like this again. Tom Last edited by T L Smith; 01-28-2004 at 10:15 PM. |
#10
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Quote:
I have ofter wondered why they used urine. Was it the salt content, or the ammonia that helped in the process. Your post made me wonder about this again. Nothing else. __________________ Mike |
#11
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Quote this Mike,
YOUR SUGGESTION TO USE PURE AMMONIA IN THIS COLOR CASE HARDENING PROCESS COULD GET SOMEONE HURT OR EVEN KILLED! Tom |
#12
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Point taken, Tom. We've been warned.
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#13
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Re: Salts to use
There are alot of different sea salts and rock salts on the market right now, what do you think blending some of these in with the bone meal would do to the steel? Or is it necessary to have the salts in direct contact with the steel via the soaked leather?
As for the end caps, would you suggest drilling a hole through one end to assist in venting? Or are you trying to prevent the majority of it from escaping? I keep having visions of the above mentioned pipe bomb!--not fun. I remember my sister made the mistake of opening a pressure cooker before it had fully vented! We found dinner all the way from the kitchen to the attic to the neighbour's yard! Thanks for the great info Brian |
#14
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Hi Brian,
A small hole in the pipe cap sure couldn't hurt just big enough to vent any steam. The salts are just to provide trace minerals next to the steel for color. You don't acually need to use either the salts or leather to get some color because there are trace elements in the bone meal. You just have to experiment to get what you want because all the variables ( steel, bone meal, leather, brine) are never the same. A really pretty case hardened piece can be a one of a kind thing. BTY, I just read my posting again and it should say to dump the WHOLE CONTENTS into the bucket of water. Sorry about that. Tom |
#15
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I belive that I read some where that having the water bubbling by some sort of aireation(sp) will enhance the pattern and colors.
__________________ Bill Burke ABS Master Smith 2008 |
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