Will Potters Clay Work for a clay heat treat??

V

VII Blades

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Dec 13, 2011
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I have a big bag of fresh potters clay and a tiny forge that heats up pretty fast. I read a guy on here say you can mix it with a little charcoal ash and fine sand, and thin out the constancy. But I wanted to make sure. I am using old files hammer forged to make a few blades and I have heard that old Nicholson Files produce a nice Hamon. The blades have some of the file texture left on the sides, so I am guessing it will help hold the clay on the blade too. Never done a clay heat treat. Any info would be great. thanks.
 
I tried potters clay a few years ago and it would not stick by itself. Never tried adding anything to it. I'd give it a try with the ash and sand in it and see if it does work.
 
I have used furnace cement that I got at an Ace Hardware for a few bucks. Thin it with water and it works decent.


-Xander
 
Your clay may not be your biggest issue. A small forge that heats fast isn't a good HT choice for hyper-eutectoid steel and trying for a hamon.
 
As far as the clay, in Japan (and I'm no expert) the smiths would mix various clays and ash and things for different areas of the sword, to achieve what they wanted -- I assume by many years of trial and error and skills being passed down in generations. Experimentation is never a bad thing, though I can't give you any specifics about the clay.
 
bladsmth said:
Your clay may not be your biggest issue. A small forge that heats fast isn't a good HT choice for hyper-eutectoid steel and trying for a hamon.
Click to expand...

I can somewhat control the heat. it is a 3 torch mini forge with map gas, but I can use a 2 burner configuration with propane for a lower heat. but I thought you wanted to heat it pretty fast do the steel under the clay doesnt reach the full 1400 degrees?? or is it more for the quench??
 
Not to be short on the answer, but you need to read up and understand the reason and procedures for a clay coat. It isn't to insulate the spine from coming up the austenite. It is there to slow down the cooling in the quench, so the spine becomes pearlite and the edge becomes martensite. The whole blade needs to be very evenly heated to about 1500F and quenched in a fast quenchant ( usually water or parks#50). If the heat isn't even, the blade may crack and break into pieces ( which it may do in a clay coated quench even if everything is right).

The process is called yaki-ire - try some searches on that.
 
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