clay hardening

R

Robert Biggin

Joined
May 30, 2014
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Does anyone have any experience with Rutland black furnace cement, or Satanite refractory cement? I have some of both, the rutland premixed, and the satanite powder clay. With the satanite, I tried quenching in water, with W1 steel, and the clay would boil off, and sometimes I would crack blades. I have recently been using rutland blac furnace cement, and quenching in hydraulic oil (still saving up for some Parks #50). Unfortunately, the 2 knives I have *successfully* differentially hardened in this manner, have an inconsistent hamon which fades away in some areas, and there are some sections of hardened steel where I had put the rutland clay. I noticed when i was heating the knives, that the rutland cement, seemed to bubble up a little. Anyone know how to avoid that?

Also, my ashi lines seemed really thick, which i suppose I can fix, by just making them thinner, but the rutland stuff is really thick and sticky. Does anyone have any thoughts on mixing up some satanite/water, and adding a bit of rutland furnace cement? Because the satanite, has usually boiled off instantly in water when I do it. But I have not tried satanite in an oil quench yet. Any one have any advice?

Bob
 
I have had good luck with both Rutlands and Satanite. With both make sure the blade is completely clean before applying the clay, that is most likely the reason you had issues with the Satanite coming off. Also, make sure it is dry and not to thick. The Rutland's seems to work best when thinned with water, and definately let it dry, or it will puff up when the blade goes in the forge.
Hydraulic oil, is unfortunately not going to be fast enough. You should be able to differentially harden the blade, but the resulting hamon will have little to no activity. Water, I feel gives the best results, but you will crack a good percentage of blades (especially at first). Parks also works very well, as the many fantastic blades shown on this forum will attest.
If you are interested in hamons, there is a discussion on the ABS forum, under the topic of the month section, that I would highly recommend reading.
 
Post some pics so we can see what is going on. Anyone who works with Hamons knows there is no set recipe, which makes it frustrating. When it works, it's breathtaking. I have done about 30 hamons (a newbie compared to most here) and have maybe 4 or 5 I was really happy with.

While saving for the commercial oil, try brine for 3 seconds at most, then finish the quench in heated canola oil. It's the second half of the marten site conversion that causes the most stress. The canola is slower than brine/water so it stresses the steel less. Temper immediately when the quench is finished to relieve stress. What austentizing temp are you using?
 
First remember less is more with hamons. Don't glob on the clay, less than 1/16 inch. It depends on how thick the blade is. Also you really need some parks, Tranny fluid is not fast enough.
 
I use satanite and quench 3 seconds in cold water then immediately I put in warm oil. Hamon is very good and they hadn't no cracking
 
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