Case hardening... make your own home brew compound?

[Technical Ted]

I've done quite a bit of heat treating years ago when I was a tool maker. D2, A2 air hardening, 1095, 4130/4140, O2, S2 and a lot of case hardening. I don't remember what brand we used, but we had two compounds that came in large drums; a finer compound and a coarser one.

I know you can buy compounds like Cherry Red and you might even get lucky and find some old Kasenit. But, I'd like to play with making my own compound.

I've done some searching and have read about using leather (after making a charcoal powder out of it), regular hardwood charcoal, baking soda, etc.

Does anyone have any experience making their own? If so, I'd love to hear your recipe! Again, I'm interested in making, not buying a compound, thanks.

Thanks,
Ted

 

[Bob Korves]

Gun lovers use their own proprietary mixtures of carbon bearing materials like leather and charcoal, along with other ingredients chosen for specific elements or compounds in them to achieve the beautiful color case hardened results. There are some listings on the web for ones people use, but they are mostly to make it pretty, not for the ultimate case hardening specs. Some of it is voodoo alchemy. Be careful, some of the ingredients people use are poisonous or otherwise dangerous. An air tight iron box packed with charcoal and your part in it will case harden the steel given the correct temperature and adequate time before quenching.

 

[core-oil]

Many years ago, In a factory in which I worked the Factory Inspector, ( Occupational Health & Safety) dropped in at lunch time, & wandered into the heat treatment department, It was a cold day, and on top of the Cyanide bath cover, was an apprentice eating his lunch & drinking his tea, To say that the **** hit the fan , was the understatement of the century, Needless to say the said department was locked during meal breaks after that occurence.

 

[KBeitz]

I take apart old D-cell battery's for the carbon rods inside.
I smash them up with a hammer and use the power.

 

[Bob Korves]

Compounds like Kasenit have additional ingredients besides carbon producers. Nitriding agents for sure. It all depends on what you are trying to achieve with the case hardening -- great color, wear resistance, ultimate hardness, a tough surface, or what? I for sure do not know the answers for all of those, but they are out there to find.

 

[RJSakowski]

From the MSDS for Kasenit and Cherry Red: Kasenit is 46% sodium ferrocyanide with the remaining ingredients not listed and Cherry Red contains about 1.5% each of potasium nitrate and chromium oxide with the remaining 97% of ingredients not listed.

It is expected that the ferrocyanide decomposes on heating and provides the source of carbon and nitrogen for creating the case. Rather than busting batteries, why not pulverize some charcoal?

Old time recipes used materials like horse manure and straw, urine from a virgin, blood, etc. Virtually any organic material contains both carbon and nitrogen. More recent recipes used ground up horse hooves, leather, and bones. Actually, epoxy grindings would probably work well. Epoxy contains about 68% Carbon and 3% nitrogen.

 

[gi_984]

I use the Brownells wood and bone charcoal. The buckets last a while.

https://www.brownells.com/gunsmith-...harcoal-sku084097031-1231-4345.aspx?rrec=true

 

[derf]

For small parts. I use a ox-acet torch method. Heat the part up cherry red, turn off the ox, and smother the part in soot, re-heat some then quench.

 

[gi_984]

I still have a can of Kasenit that I use for quick and simple surface hardening of small non-critical items. Cans might still be found at garage sales, Craigslist, etc. Even saw an unopened can for sale on E-bay. Zero experience with Cherry Red.

EDIT: Guy Lautard's The Machinist's Bedside Reader volume three has a very good write up on how to do it. That is making the compound from scratch and hardening parts.
Only addition I would add to that tutorial is to tightly pack any threaded holes in the workpiece with fine steel wool to prevent brittle threads.

I'd like to Rockwell test some of my shop hardened stuff to see just what hardness was achieved. Anybody do this to their parts?

 

[AGCB97]

I'd like to Rockwell test some of my shop hardened stuff to see just what hardness was achieved. Anybody do this to their parts?

I know of a Service Diamond tester one could probably get pretty cheap and only about 3 hours from you.
Thanks
Aaron