Easy access clay HT material

Chiro75

Chiro75

Joined
Feb 4, 1999
Messages
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Well, I finally bit the bullet and tried to do a Japanese style clay heat treat on that tanto. I think I may have just pulled it off, although I doubt I got a very consistent critical temp on the blade. A file skates off the edge, so I guess I did it, but I can hardly believe it. That's the last big blade I do until I get a proper heating forge made or something. Sheesh. Anyway, I couldn't find "refractory materials" in my yellow pages, and I got a recommendation to try Red Devil furnace cement, but I couldn't find that either. I went to Lowe's today and found fireplace caulk stuff in the Caulk/Adhesive ailse. It's supposed to be good to 1400 degrees or something, so I thought I'd give it a shot. I think it actuallyu worked! It comes out real runny at first, so squeeze it until it comes out like toothpaste (it's in a regular size caulk tube sort of format. Sells for $2.75). Anyway, I spread it on with my finger about 1/4" or so, let it dry (less than an hour) and applied a bit more to get a pattern and get even thickness on the part of the blade I wanted to stay soft. I didn't wire it up or anything and it adhered to the steel with no problem at all. Good stuff. Anyway, I can't really tell you how it did because I don't have an Rc tester, but I can see a nice hamon with the blade finished to 220 grit or so. I am tempering the knife right now, so we'll see how it progresses, but this could be a good resource for people who want a cheap and easy alternative to satanite and that sort of stuff. I'll keep ya posted!
 
Well, the hamon turned out okay. The edge is not hard, though. It rolls right over with a brass rod. The tip hardened, but most of the thing is dead soft. Unfortunately that's a lot of work down the drain, unless you can just take another whack at gettiong up to critical, which I don't think is as easy as that. Good thing is that it is cheap steel, but the bad thing is that it represents a dozen hours of hard work down the tube. Very disappointing. I guess I will need a makeshift forge of some type to get anything over 3.5" to critical. What a bummer!
 
What steel did you use, cuz depending on the steel, no reason you shouldn't try it again
 
I used 1084. I had the understanding that you just can't redo it that easily, that you have to get it really hot and cool really slowly to re-anneal the steel and start over. If someone wants to donate their furnace, I'll reapply the clay and send the knife. All you'd have to do is bring it to critical and quench in warm oil, throw it in a box and send it back. Anyone?
 
What kinda forge or torch did you use? I have used a little 1 soft firebrick forge with a propane torch to get above critical on small things like that, and it looked like a pretty even temp as i passed the blade back and forth inside the brick.
 
Terry, my setup was ridiculously stupid. I won't even share it with you. I did, however, find a supplier of firebricks in town. There's a brick supply place that does fireplaces, too. You would think that I would've thought of that sooner, but no. Anyway, there were two sizes: really thin and something about like what a regular sized brick is like, so I figure I can wire two together and dig the middle out (they're very brittle) and make a one-brick forge ala Goddard. Can't wait!
 
Did you check the steels temp with a magnet?You stated that a file just skates off the edge and that you can see a hamon.......hmmmm,sounds like the edge got hard,I wonder why it`s not passing the brass rod test?hoow far up the edge does the hamon go?
I see no reason why you cant go back to the fire,dont anneal it again just reheat and quench it.
1/4" thick refractory caulk???hmmm,might be the problem there,that seems a bit thick.
Give my instructions in the other post another try,follow them closely and I bet it will work.If it doesnt send me the blade and I`ll do it for free.
Hope you succeed.
Scott
 
Chiro75

I can help you out if you can wait for about a week. I only live about 30 Miles from Holland.

I have a forge and an oil quench tank. I had no problem getting a 9 inch blade (1095 and 15n20) to RC 60 (after temper).

If you are interested, let me know. Shoot me an email, and i will get back to you after I get home from vacation (10/08/02).
 
I dunno. made my little forge and got things going, and i hardened the part that didn't make it before, but that made the tip area that previously hardened soft. i'm through with this thing. starting over!
 
Hey Chiro,

Send it to me and I'll see what I can do with it.

Nick Wheeler
1109 N.W. Mill St.
Winlock, WA 98596

Some advice: 1084's austenitizing temperature is around 1450/1500 F. So you'd be better off with the 2000 degree caulk they sell there. Personally I use either satanite or a mix I make myself.

The magnet trick is helpful, but most low alloy steels will lose their magnetism BEFORE they are at their actual austenitizing temperature.

With a blade that doesn't get as hard as you wanted, I would recommend you normalize it twice and then take it back to your critical temp and quench.

Like I said, send it my way and I'll see what I can do (no $, just to help you out).

Nick
 
Scott Fulford how thick should the refractory caulk be? Do you still need to do a very very thin wash on the entire blade and let it dry before you put the thicker caulk on everywhere but where you want the hamon?
 
well,Chiro75 is using a different product than what I normally use but I dont think thats the problem,it seems like I used a black gritty caulk like substance in the past and it worked the same as the stuff in the tub but who knows.....
Anyhoo,here`s a link to the thread where I posted my way of doing it....
http://www.bladeforums.com/forums/showthread.php?s=&threadid=221625
Take a look at the third pic in the post,I guess about 1/8" should be plenty,what you want to concentrate on is the edge,you want the overall average temperline to go up to about a third of the way from the edge to the spine,that way you`ve got enough hard steel to give the blade some stiffness but you still have the two thirds of the blade soft enough to resist breaking.The "ribs" of furnace cement on the blade in the pic are not more than 1/8" thick,they taper in width and thickness down to the edge,I glob the cement onto the back to insure that that area doesnt have a chance to harden.Keep the tips of the ribs at least 1/4" away from the edge,nothing sucks worse than the soft part of the line dipping down into the edge,a little trial and error will give you a good feel for the process but I really do believe that if you follow my instructions you will have success.
I`ve seen plenty of books and posts where the bladesmith will glob the clay or cement on all over the blade and remove the stuff from where he wants the hardness to be,I`m in no position to argue with most bladesmiths as I`m still quite the newbie but my method(and it`s not really MY method I got this from "blade" magazine about 6 years ago or more) has worked quite well and gives a beautiful line.
As far as the wash goes,I think it serves the purpose of giving the thicker stuff something to grab hold of,it really should be no thicker than a coat of paint,it`s just a base coat but I do it everytime and it seems to work.
One thing I`ve noticed is that this method will show a bit of surface decarburization which will follow the outline of the ribs,so grind the blade with this in mind and leave the blade a thousandth or so thicker than normal before the quench so you can pretty the thing up after you`re done .
ViewImage.dll

Scott
 
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