Found a "clay" for hamons in an old patent.

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May 4, 2016
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So, a while ago I needed to cast something in aluminum that had internal voids, and I found this patent- pat.#US6024787. It worked great and I actually ended up using it for lots of other things, like coating kaowool, metal furnace hardware, tons of stuff. Recently, I tried my first hamon (I'll post a picture when I can) and since I had this stuff lying around, I tried it. It worked GREAT. From everything I have read about what makes a good clay for coating blades, this stuff fulfills pretty much all of them. It sticks like glue and can survive thermal cycling, you can control if it pops off in the quench by varying the amount of trisodium phosphate, it has sugar in it which carbonizes and protects against decarb, and best of all, washes off with water with a bit of scrubbing.

I don't use the exact formulation, either. The key ingredients are sugar, trisodium phosphate, and a refractory filler. Just about anything will work as long as 10 percent or so of the filler is a very fine powder. Personally, I use alumina flour and 325 mesh mullite from a ceramics supplier along with cheap sand from lowes. You don't really want to use clays that shrink as they dry, though. If you do, you cant put the wet clay directly into the hot furnace or it will pop off from steam expansion.

You can get pretty much everything needed from walmart and a hardware store, so it's certainly easy to come by, and I thought I would share it. I'm fairly confident no one has every tried it before:)
 
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