Rehardening India musket Frizzen with leather

[keithgill]

I'm coming up to an event and need to reharden the Frizen on my 1980s? India made replica Brown Bess.

I want to try the technique using leather wrapped around Frizzen and putting inside a metal can and heating in the fire.

My question is, I bought some leather scraps but had a lot of choices of animal and tanning style. Will the tanning process of the leather impart any harmful chemicals to the steel during the heat? Such as Deer vegatable tanned, Bison oil tanned? deer oil tanned?

Am I overthinking it? :hmm:

Thanks.

 

[shunka]

What you are describing sounds like color case hardening, and may not work well for cheap frizzens.

I myself used to use casenite, but it is no longer available and since I haven't done it in so long, I had to go look it up.

try these three sites:

from Track of the wolf:
track of the wolf

DIY from a flock of hivernaughts I know
bunch o' brits

from the "pro's" on American Longrifle
amer longrifle

hope this helps
shunka

 

[Phil Coffins]

I've done a lot of case hardening and color case hardening over many years so my advice is based only on my experience.
The leather should be made into char coal by placing it in a nearly sealed can. Put that in the edge of the fire and keep it hot till it quits smoking. That will burn off the oils and convert the leather into char coal. When it's cooled the char coal should crumble. From the camp fire gather a few of the black coals of wood and crumble them to mix with your leather char. What does the case hardening is the carbon dioxide and carbon monoxide released in the heating with your part. The color often seen is merely a by product of the process. Mix the leather and wood char any where 1 to 1 and as much as 1 to 4 to pack your part in. Make sure the part is well covered with at least 1/2" of char on all sides(more is better). Heat the closed but not sealed can to red hot for at least an hour or as long as 4 hours but it must stay red hot. Quench in cool water from red hot. Then draw the part in an oven at 375 degrees for a full hour to stress relive. Lightly oil when cool.
Siler by Oliver Sudden, on Flickr

 

[dave_person]

Hi,
Phil's method should work well. I only would add that you don't know what steel was used by the maker. It is probably pretty low carbon if they cased it rather than through-hardened it. Anyway, just to be sure, after hardening, I would oven temper the frizzen as Phil described and then slowly heat the toe of the frizzen with a butane or propane torch until it turns to a deep blue color. Keep a little spray bottle of water on hand to cool the pan cover and frizzen face if the color starts to migrate beyond the toe. Another option for you is to solder a hardened sole on the frizzen face rather than harden the frizze. Unfortunately, on most Bess locks the sole will not clear the pan fence when the frizzen is closed but perhaps it might on yours.

dave

 

[Zonie]

Before you get into carburizing your frizzen, first find out if it needs it.

Using a good metal cutting file, try to file the surface of the frizzen.

If the file just skids across the face only leaving some bright areas where it scraped off some of the accumulated oxides that are usually present, your frizzen is hard enough to work without any hardening at all.

If the file starts to cut into the surface, removing small amounts of steel, your frizzen needs to be carburized and rehardened.

If it does need to be re-carburized and hardened remember, the frizzen will have to be heated to a temperature of at least 1500°F. and kept at this temperature for over 15 minutes. That's a bright orange color.
If it doesn't reach this temperature the carbon around it will not soak into the steel.

Also, this temperature is needed before quenching the part to get it to harden.

If the part is allowed to cool to a dull red or black color before quenching, the steel will not harden at all.

 

[dave_person]

Hi,
OK, here is the deal. The depth of the carbon penetration or case is dependent on heat and time. You can successfully harden mild steel at as low a temp as 1350 degrees but it takes a lot longer for the metal to absorb the carbon. At 1475-1550 the metal will absorb an adequate depth of carbon for a frizzen if heat soaked for at least 90 minutes. You can go hotter but you have a higher risk of cracking the metal when quenching. Products like Kasenit or Cherry red are powders that efficiently add carbon to the metal but you cannot speed up the process very much. If you heat soak for 15 minutes your case will be very thin despite using a product like Kasenit. Moreover, the part must be packed completely in the charcoal so no air contaminates the surface or you will get scaling and burned metal.

dave

 

[Davemuzz]

Propane gas burns at 3,600 F while Mapp Gas burns at 3,730 F. Many (not all) promote the theory that Mapp Gas is far superior to propane.....but does 130 degrees really make that much of a difference? :idunno:

 

[44-henry]

Case hardening (even color case hardening) is not difficult with the right equipment, but without a good furnace that allows you to accurately set temperatures it becomes more difficult. Small parts can be successfully hardened with a torch and kasenite if you are content with a shallow case, bigger parts like a frizzen really need longer soak times to get the depth you need for something like a frizzen. With good carburizing mixtures (charcoal by itself is not great) you can expect about .020 depth at 1550 degrees F after a 4 hour soak. At lower temperatures the carbon penetrates at a much slower rate.

The problem with color case hardening is the best colors occur at lower temps than this, I generally do them at around 1450, around 1500 they start getting too dark for my taste. The other problem is that the traditional wood/bone/leather mix is not an exactly ideal carburizing compound. Keep in mind the colors are purely decorative and say nothing about the hardness of the surface, some of the best colors actually occur at temps less than critical where the phase change occurs resulting in less than optimal hardening.

With that all said you can do the job, but it might not be as simple as you might first think.

 

[Scota4570]

Propane gas burns at 3,600 F while Mapp Gas burns at 3,730 F. Many (not all) promote the theory that Mapp Gas is far superior to propane.....but does 130 degrees really make that much of a difference? :idunno:

I can braze small parts with MAP, but not propane, I guess that is a difference.

 

[Black Hand]

Propane gas burns at 3,600 F while Mapp Gas burns at 3,730 F. Many (not all) promote the theory that Mapp Gas is far superior to propane.....but does 130 degrees really make that much of a difference? :idunno:

Metals have a specific melting & critical points - as such, even 1 degree could make the difference...

 

[LRB]

The torch units for MAPP gas work very well with the common propane cylinders, as they provide more air to the flame. When I silver braze, that is what I use for thicker metal. Normally a common propane torch with propane gives plenty of heat for brazing thinner metals. I use SILVALOY 355 for most brazing. Flows nicely at 1200°.

 

[Loyalist Dave]

I want to try the technique using leather wrapped around Frizzen and putting inside a metal can and heating in the fire.

Yeah I've seen this done on YouTube and it's balderdash. They would get the same results if they simply put that frizzen into the fire without the can, let it set and heat up (maybe with a lad or two with a blow poke to up the temp and get some color into the frizzen), and then quenched it in water. The can doesn't seal enough of the air out so all that's being done with the leather is incineration, and the amount of carbon that one has remaining after conversion of the leather would be miniscule compared to a proper carbon packing. What you see is a slight discoloration of the frizzen metal from exposure to the gases from the burning leather within the can..., and the frizzen sparks a little better since it's a little harder than before it went into the fire.

The frizzen probably had enough carbon in the video, it just wasn't well heat treated. IF you follow the instructions on the previous posts, you will get a properly controlled heating, to the proper color, and you can if you wish use Cherry Red to ensure a good, end result. Followed by a proper quench and then proper tempering.

LD

 

[LRB]

Very good Dave. I completely agree. Excellent advise. :thumbsup: :hatsoff: