# methods of case-hardening?



## markba633csi (Jul 21, 2017)

Are there non-toxic ways of doing it?  IIRC it used to require cyanide.
Mark


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## RandyM (Jul 21, 2017)

Here is a method. They claim no Cyanide. Not sure what the composition they are selling though.

https://www.rosemill.com/category_s/46.htm






Here is the Safety Data Sheet

http://www.rosemill.com/v/html/msds/Therm_cherry_MSDS.pdf

OK, definitely not non-toxic.


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## benmychree (Jul 21, 2017)

Cyaniding was used to create a fairly shallow case, a better course was to use a carbonizer, sometimes charcoal, sometimes old leather belting, also charred with various other ingredients, and "activators".
I think cyanide may have also been used in that process.  It took many hours in a furnace, packed in sealed iron boxes to do the job.  Nowadays, about all that is available is "Kasenite", a proprietary compound for casehardening; the object is heated red, dipped in the powder, perhaps reheated a few times and re dipped and then quenched in water.  This also provides a relatively shallow case, and is rough on finished parts, but is safe to use.  If I had parts to case harden, and they needed deep case hardening, I sent them out to a heat treater and specified depth of case and hardness desired, generally full hard for wear parts.  A look in an OLD edition of Machinery's handbook or American Machinist's handbook would likely provide some more info on recipes for hardening compounds that could be made up.


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## benmychree (Jul 21, 2017)

RandyM said:


> Here is a method. They claim no Cyanide. Not sure what the composition they are selling though.
> 
> https://www.rosemill.com/category_s/46.htm
> 
> ...


Cherry Red Compound is roughly the same animal as Kasenite, used in the same fashion.  Rockwell C testing is not reliable in the case (no pun intended) of thin case hardening, the indenting device is liable to partially punch through the very thin hard layer and give a false reading, generally on the low side of actual surface hardness.


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## benmychree (Jul 21, 2017)

I looked up the MSDS sheets for both Cherry Red and Kasenite compounds, Kasenite lists only potassium ferrocyanide and the warnings are much less scary than Cherry red, which lists potassium nitrate and chromium oxide.  Ya' pays your money and takes your chances ----.   We used Kasenite in school machine shop classes, and I have used it occasionally over the years without ill effect, have some Cherry Red, but have never used it.  I think if either is used with good ventilation and not eaten, that both are probably safe to use on a limited basis, that is not all day and every day.


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## rgray (Jul 21, 2017)

And cherry red is available from Amazon:https://www.amazon.com/CHERRY-RED-T...rd_wg=JpU3K&psc=1&refRID=79W0BVZC4CQ2XVVFYSDF

Thought I got mine from Brownells but can't find it from them at the moment.
midway shows it but as out of stock.
Just thought I'd add this as a google search for "cherry red" brings up nothing of interest.
I did figure out that searching "cherry red case hardening compound" Works much better.


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## royesses (Jul 21, 2017)

This is what I have:
	

		
			
		

		
	



http://www.brownells.com/gunsmith-t...ing/surface-hardening-compound-prod27119.aspx


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## savarin (Jul 21, 2017)

Heres a video of how to make your own files out of mild steel and hardening them.
All this gentleman's videos are superbly shot and edited.


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## markba633csi (Jul 21, 2017)

interesting, thanks
M


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## chips&more (Jul 21, 2017)

benmychree said:


> Cyaniding was used to create a fairly shallow case, a better course was to use a carbonizer, sometimes charcoal, sometimes old leather belting, also charred with various other ingredients, and "activators".
> I think cyanide may have also been used in that process.  It took many hours in a furnace, packed in sealed iron boxes to do the job.  Nowadays, about all that is available is "Kasenite", a proprietary compound for casehardening; the object is heated red, dipped in the powder, perhaps reheated a few times and re dipped and then quenched in water.  This also provides a relatively shallow case, and is rough on finished parts, but is safe to use.  If I had parts to case harden, and they needed deep case hardening, I sent them out to a heat treater and specified depth of case and hardness desired, generally full hard for wear parts.  A look in an OLD edition of Machinery's handbook or American Machinist's handbook would likely provide some more info on recipes for hardening compounds that could be made up.


Sorry, but Kasenit is no longer available. Sometimes fleaBay has a used can of it for a ludacris price. If you have a can of it, and tell us, you could probably get half the folks on HM to cry…Dave


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## RJSakowski (Jul 21, 2017)

Potassium ferrocyanide is not the same as sodium or potassium cyanide.  It used to be one of the chemicals included in a Gilbert chemistry set when I as a lad. From Wikipedia "
*Toxicity*
Potassium ferrocyanide is nontoxic, and is not decomposed to cyanide in the body. The toxicity in rats is low, with lethal dose (LD50) at 6400 mg/kg.[2]"
Chromium compounds, on the other hand are considerably more dangerous due to their ability to form hexavalent compounds. Nowadays, you get an MSD sheet when you buy HSS tools containing chromium because of the possibility of inhaling chromium containing dust when regrinding.

The depth of case hardening depends upon the length of time that the red hot steel in in contact with the case hardening compound.  Both carbon and nitrogen contribute to case hardening.  Cyanide and ferrocyanide compounds both contribute carbon and nitrogen to the case. Medieval blacksmiths used exotic materials for case hardening or for converting iron to steel, including urine, blood and dung mixed with straw.  Japanese sword smiths used similar mixture, all highly guarded secrets for making the superb steel use in making Samuri swords.


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## Whyemier (Jul 22, 2017)

If no one mentioned, check out 'ClickSprings' videos on YouTube. He made some files (the old way) from mild steel and case hardened with a mixture of carbon (carbonized leather) salt and flour. Made a paste, completely encased the item to be case hardened, then heated in furnace for a minimum 20 min. It's all part of his Antikythera mechanism recreation.


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## savarin (Jul 22, 2017)

Please mister Whyemier, I did.
All his vids are excellent


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## Wout Moerman (Jul 22, 2017)

The Clickspring video is great. Does anyone know what the table salt does? 

 I might try this using organic fertilizer with ground bone and hoof. But I wonder if I should add a pinch of salt. Please, no jokes about the taste ...


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## RJSakowski (Jul 22, 2017)

I expect the salt just acts as a binder or flux.  Salt of it's own has no ability to harden steel.

I have hardened low carbon steel in a coal fired forge by burying it in a bed of coke.  The secret is to keep oxygen away from the steel while keeping it at a bright red heat as the oxygen will burn the carbon out.  Clickspring does it with his paste and a reducing flame.  If you have access to an electric furnace, simply burying the steel in a bed of the case hardening material should do the trick.

"The Modern Gunsmith" by James V. Howe has a good write up on case hardening as a lot of other interesting and valuable information.  Modern is a bit of a misnomer since the book was first copyrighted in 1936.  He mentions materials like charred leather, powdered bone, and animal charcoal (presumably an extremely well done roast).

The book can be read on line or down loaded. It is also available in hard copy from Amazon.
https://archive.org/details/The_Modern_Gunsmith_Vol_1_Howe_1941 

The pertaining section is in Chapter 7 in volume 2


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## Silverbullet (Jul 22, 2017)

I have a new can of kasenit in my attic along with hard and soft polishing wheels with about ten pounds of different pastes and other goodies for doing barrel rebluing  on guns. I had the frame built for the tanks the burners made . Big plans to be a gunsmith , courses all done everything approved . Then things changed three spinal lamenectame in three weeks. A life I had worked for shot down in three weeks , couldn't move or do anything . Being paralyzed from the neck down fixed my dreams of a good life. 
So there in the attic after we lost everything because of transverse myilitis .


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## Wreck™Wreck (Jul 22, 2017)

If you have  no reliable method of testing a parts surface hardness every single  You Tube video of how to do it is pointless.
Harden it, test it with your RC tool and report back here, it is that easy.


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## Whyemier (Jul 24, 2017)

savarin said:


> Please mister Whyemier, I did.
> All his vids are excellent



Ogee! Missed that.


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## KBeitz (Oct 3, 2018)

Carbon rod out of old D-cell batteries work great for this.
Beat them into power with a hammer.


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