How to get clay to stick?

samuraistuart

samuraistuart

Joined
Dec 21, 2006
Messages
3,158
Guys, I would GREATLY appreciate your help here. I'm about at wits end. I'm trying to do a diff heat treat. On a knife with a 4 inch drop point, I have it sanded to 320, and then sprayed it with carb/choke cleaner, and wiped off with a clean rag. I'm using AP Green #36, which is used by knifemakers everywhere, as my satanite. I tried applying the coat directly to the metal, without a thin wash underneath. Maybe 1/16"+ thick. When it dried, it dried with craks in it, and you could break it off very easily. I've tried applying a thin "wash" across the entire surface of the blade, and then applying the thicker coat along the flats above the edge. EVERY time I do this, no matter what, the clay cracks when dried and falls off relatively easy.

What in the world am I doing wrong? I have tried this over and over and over. I've tried letting it air dry slowly, I've tried putting slight heat to it, medium heat to it, you name it.

The only varaiable my feeble mind can come up with is the water content IN the clay itself. Too much? Not enough? When I apply it, the consistency isn't too watery. Too watery and you can't put it where you want it. Maybe I'm still using TOO much water. Thanks again for your comments and suggestions.
 
I can't help with the AP Green as I use satanite; however, here is my process. I start with the blade at a 400-600 machine finish. I wash the blade with soap and water first, rinsing really well and then spraying with a bit of windex and drying. Then I clean with alcohol which doesn't leave any sort of oil film or residue. Then I do a thin wash with watery satanite (letting it dry) followed by claying with satanite the consistency of a thick milk-shake. I have not had issues with cracking during drying. I even use a small butane torch to help the satanite dry. You can watch the water vapor-off with the heat, and the satanite changes color when it dries. After qunench, the clay snaps off cleanly with pressure.

--nathan
 
Similar to Nathans style. About 400grit finish, clean very well. Then I take my wash consistancy satanite and a paper towel and wipe it all over the blade. Seems to make it adhere really well. Then wipe most of it off so there is just a film of satanite. Then apply the thicker stuff. Then I will put the blade in the forge while its heating up and do another normalization basically bring it up to temp then let it cool to black. Then it goes back in for final temp/soak/quench. The satanite usually has to be ground or scraped off with a sharp edge.
 
I have to use a thin wash to get it to stick but it does pretty well, I am sure the carb cleaner is leaving a residue, its very volitile but probably contains other solvents and hydrocarbons just to give more kick. I use alchol for pretty much everything.
 
Its been a while since I've had to use it, but doesn't the carb cleaner leave a slight oily residue?
 
I wash with detergent and water a couple times, air dry, and apply satanite wash. After quench I have to scrape it off with a chisel.
 
Same as Salem, I wash and let air dry then apply the satanite directly with no other solvents or cleaners. Mine has to be ground off or scraped off. Make sure you don't touch the blade or let it come in contact with anything that will contaminate it. That usually causes problems with it not sticking.
 
As the above guys indicate, use a thin satanite wash, and sort of scrub the blade with it. This make it adhere well. After drying the wash coat, apply 1/8" of the thicker stuff....and that is 1/8" MAX!. anything from .060" to .120" seems about right. Once you get a system that works....Don't Change It. Repeatable results are hard enough in a hamon. Making them when there are changes in the clay coat and thickness will make things worse.
 
Most excellent! Thank you all so much. I have a hunch that my carb cleaner is leaving a film behind. I will also go up to 400 grit. I keep that AP36 stuff in a tupperware container, and there's enough in there to almost come to the lid, but not quite. I add water to it before I seal it up, if I'm not going to use it. If I use it, I pour the layer off water off, and use the thicker part (usually at the bottom, I bring it up and mix it up...about like a thick milk shake like the gentleman said earlier) Like I've said, I've tried this before on my first knife, same thing....the clay cracks after it's dried. So I went with a full hardening. My second knife, I was hell bent on a hamon, and.......cracks. So I through hardened my second knife yesterday. Third times a charm?
 
I also use Satanite with pretty much the same procedure as the other guys. The only thing I do different is I mix the Satanite with denatured alcohol. I find that it dries much quicker.
 
the ap36 shrinks somewhat when dry which doesn't help with sticking. I get fine grog from a pottery supply center and add it to the ap36 until it stops cracking.
 
Pretty much the same as Don. 120 grit belt finish, clean, and apply satanite. I do not use a thin wash on blades quenched in parks. Have to scrape the stuff off afterwards.
Brion
 
One thing I will caution about Rutlands is to be sure it is smoothly and evenly applied. The only time I've used it, I had some pitting in the steel at spots where there was apparently an air bubble. It was so sticky I had problems getting it applied consistently. With careful application, it will do the trick just fine.

--Nathan
 
There's a couple of versions of Rutlands, isn't there? I've seen the black stuff, and there's a concrete colored version as well. I've only used the black, but from what some guys have said, the concrete is pretty similiar to satanite. ???
 
Mike Quesenberry said:
I like the rutlands black smooth stuff, not a fan of the higher temp gray.
Click to expand...

I am confused Mike. I know, nothing new there. :o;)
I got the 2000F you recommended and it is not black.

WIP_Kukri_49_zpsdeb2b711.jpg
 
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