i wanted to heat treat a dagger I made from a rasp, but i didn't have any clay. I used some refractory cement instead and it seemed to work all rite. I was wondering if anyone had done that before and if anyone could tell me how it works. thanks.

Hhmmm... I haven't tried that. Clay is not TOO hard to find here in MO.

unfortunatly here in my little corner of n.y. there is plenty of clay, but it is very brittle when it drys and won't really stick to the steel very well. I don't have the funds to buy the rite clay or even the rite stuff to make the clay. I bought the refractory cement a long time ago and never used it. I hope that it made a nice hammen line.

Lots of guys use various refractories as their clay. No reason it can't work. What type of steel did you use?

The late Bob Engnath used refractory clay with great success, even still, many bladesmiths working in the Japanese style work with refractory cement or mortar, usually mixed with other ingredients, like charcoal powder, for extra insulation.
I have used clay so far and it usually cracks a little but works great, I just dry it for one or two days and repair any cracks. From building my forge I have a lot of refractory cement lying around and I intend to experiment with that.

In the end, it doesn't matter what you use as long as it serves the purpose you're after: that is insulating the spine of the blade so it cools more slowly. Almost any concoction can work as long as it does the following two thing:
1: Insulate the part not to be hardened.
2: Stick to the blade and not crack or fall off during heating in the fire or upon quenching.


My advice: take a peace of metal, rough it up with a grinder or 80grit sandpaper so the clay/refractory will stick, put your Hamon-mix on the metal like you would with a blade, put it in the fire, heat it up, and quench it.
If it cracks or falls off, experiment with other mixes, if it stays on the blade, I can almost guaranty you it will work for a blade.

Good luck and let us know how it went.

Louis

it actually worked really well. no hammon line, but then again, i havn't finished polishing it yet. the refractory stayed on beautifully and it was actually kind of hard to get off. i think that i will continue to use it on blades to come. in fact i'm about to use it on a miniature seaxe that i have recently finished shaping from yet another rasp. but on this one i think that i'll apply a slightly thicker layer and maby do some cross patterning on the blade it's self. try to get a nice design out of it.

yes, If you have a hamon it can take a lot of polishing to reveal it, Japanese Togishi (sword polishers) can take two weeks to finish a blade.

One of the first blades I made with a Hamon I polished up to 1000grit and it still needed an etch with vinegar to reveal it, but then again, it was pretty louse steel

What steel did you use? That can explain a lot, because not every steel will show a hamon well.

i'm honestly not sure just what kind of steel it is. it's an old horse shew rasp, maby 80 years old or so. i do know that i had to anneal it twice to get it soft enough to work with.

i'm honestly not sure just what kind of steel it is. it's an old horse shew rasp, maby 80 years old or so. i do know that i had to anneal it twice to get it soft enough to work with.

Well, I have no idea what this steel could be. I don't think it's be good for a Hamon, but thats a guess at best.

i tried mixing some wood ash from the fire place water and some modeling clay and it worked ok however i didnt allow for it to dry does it work better that way? and does anyone else think that Japaneses bladesmiths make putting on clay in a nice pattern easy ha ha i tried it and it was way harder than i thought it would be anyway thanks jake

yes, putting on the clay is an art in itself. If the thickness is uneven, the blade can warp. If you put too much clay on the back of the blade, the blade might curve to much and might even crack because of the stress. Ashi can be to thick or thin, and so on...

To answer your question, no, it is best to let the clay dry thoroughly, it will shrink during drying and you might have to patch it up. If you dry it in the fire, the clay is sure to fall off, making it useless.