What can I use to clay temper a blade and where can I get it?

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chopsuey9999

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Feb 17, 2007
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Hi all, long time lurker and new backyard knife maker here. I'm making a blade out of O1 and I've been looking everywhere for some clay(satanite, apg#36, ITC 100, you know the deal, haha) to use for the hamon. Anyone know where I can get some of that stuff in small quantities? (I live in Toronto-Scarborough area so if the place is close that'd be nice :) ). And on a side note, I checked a Rona a few days ago and they carried something called pyromix mortar (used for fixing fireplaces and the like). I would also like to know if that's suitable for clay tempering. Thanks in advance!!
 
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Welcome! The hamon you get with O1 wont be as nice as with a fast steel. I have seen some nice hamons done with furnace cement (I think that is what it is called)
 
You can buy APG and Satanite from Darren Ellis, Ellis Custom Knife Works. I don't know for sure if he ships to Canada. All of the furnace cement "hamons" I have seen come from very thick applications of the cement resulting in just a well defined line. The satanite can be applied very thin and thicker in some spots so you can do finer details of a hamon like ashi, the APG is a pain in the rear, in my opinion. Bob Engnath figured out a good way to do it, but I think he took it with him. Scott Slobodian told me forget about the APG and the putty knife, use satanite and bamboo skewers to apply, it works well. Flux brushes and craft sticks also work well.

The O1 is very deep hardening, you can get a transition but you won't be able to get the depth of activity you can with a shallow hardening steel like 1095, W1, or W2.
 
A lot of people use satanite and many other products, but I and many of the guys I pay attention to use good old furnace cement. I have done tests side by side on the same blade with satanite and furnace cement and found the furnace cement gave me better insulative control of the hamon. I should also say that I am referring to a very specific cement but it is available in most good hardware stores or other places that sell fireplace and stove supplies. It can be bought in a small plastic tub or in a caulk type tube and is black, but most importantly is rated for 3000F. Mix a portion of it with a bit of water and apply with a popsicle stick or better yet a pallet knife just like any other ashi. I know the type of thick application AcridSsaint describes and I think those folks are not taking it to the right consistancy for proper thin and precise application. The stuff seems to work best when you allow it to dry down just enough not to puff up from steam expansion, but not enough to allow it to shrink and pull a bit. Applied and dried right on a blade finished no finer than 200X it will stick quite well through the heat treatment and pop off clean with a sharp tap on the spine of the blade when the quench is done.

Now having said all of that, you would be wasting good furnace cement and really good steel using this method on O-1. O-1 hardens deep enough to simply ignore any ashi you may apply, and the length of time for proper solution with O-1 in the heat will also work against what you are trying to do. Some folks would argue that by just heating the edge or only edge quenching that you can get a line on O-1 but this is a matter of forcing a $5 steel to act like a $1 steel when you could get even better effects using the $1 steel.

Some steels you want for this technique would include, 1070, 1080, 1084, 1095, W1 or W2.
 
Thanks for all the replies guys for all the useful tips. :o too bad O1 doesn't work too well for what I'm doing, but I'll keep this in mind for my next project! Again , thanks everyone! :)
 
I got this hamon in 1095 using furnace cement. O1 won't make much of a hamon, though you may get a faint transition line.

IMG_7570.jpg


IMG_7559.jpg


Here's what it looked like before hardening. I applied about 1/8" of cement to each side and used an interrupted quench.

IMG_0154.jpg


--nathan
 
silver may I ask when you apply the compound to both sides, Do you try real hard to make sure it looks the same on both sides or do you just eyeball it to make sure its close? I was going back and forth thru the pics and I notice the hammon line isnt truly the same on both sides. So I was wondering if its meant to be exact or just real close.? Oh yea and thanks for the pics I was kinda wondering how it was done.

Bennie
 
Bennie,

A hamon is more of a living and breathing thing than a rigid and drawn-on proposition. I work to get the clay close on each side, but even if it was perfectly symmetrical, there would still likely be some differences side to side. The sides will be close, but with some variation. Even with deep hardening steels like 1095, subtle changes in where the martensite / pearlite transition is will happen. That's what makes hamons so wonderful. They can be very unpredictable. The clay only serves to help control the heat, and your hamon won't follow the clay exactly.

--nathan
 
Kevin - thanks for explaining how you do it with furnace cement. The black stuff you're talking about is what I was thinking of, but I think I've generally just seen it done with the premixed consistency clay. Thinning it with water would allow the same kind of control you can get with mixing your own, so I can see where that could be a winner.
 
Is there a particular reason everyone is mentioning certain applicators. Does it really matter what you use to apply the furnace cement.
 
silver_pilate said:
Bennie,

A hamon is more of a living and breathing thing than a rigid and drawn-on proposition. I work to get the clay close on each side, but even if it was perfectly symmetrical, there would still likely be some differences side to side. The sides will be close, but with some variation. Even with deep hardening steels like 1095, subtle changes in where the martensite / pearlite transition is will happen. That's what makes hamons so wonderful. They can be very unpredictable. The clay only serves to help control the heat, and your hamon won't follow the clay exactly.

--nathan
Click to expand...



it's funny you say that, because control of the hamon is something I've been trying to work on for quite a while now ( atleast in my time in knifemaking).
You really have to narrow down all the tiny variables and take notes.
Clay thickness,symetry,etc. and even then you will can get a few surprises with differing batches of steel
 
Wade - I think the only reason we post them is because that's what we've found to work best for us. I tried for a very long time to use the putty/spatula technique that Bob Engnath wrote about, but could never get it to work right for me.
 
WadeH said:
Is there a particular reason everyone is mentioning certain applicators. Does it really matter what you use to apply the furnace cement.
Click to expand...

I have found that getting what you want from ashi is a combination of placement and the amount of peaking in the clay/cement in the ashi line. A thin application with a very flat line from watery mix is not very effective, while a very nice crisp line, were you want it, with a good peaked ridge down the center without being too high is ideal. It is one of those things where I can't really describe it here but I know it when I see it and put some effort into achieving it when claying a blade. It is the result of three things- 1. the consistency of the furnace cement, 2. the way the tool catches and deposits the cement and thus... 3. the shape and size of the tool used to apply the cement. I normally make my own little wooden knife like spatula tool to do it but in a pinch a palette knife or Popsicle stick with it edges slightly narrowed will work. Everybody gets use to doing it in different ways, I apply it with a palette knife much like I learned years ago in oil painting, but my friend Rick Barrett gets very good results by mixing the cement to a slightly different consistency and allowing it to form strings off the palette knife which he guides onto the blade.
 
Excellent information in this thread. In "Knives 86" pg. 128, Bob Engnath has a article on how he used clay to get a temper line.
 
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