Lil' (big) something I just started...questions on clay coating

David Schott

David Schott

Joined
Sep 27, 2004
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Heres the biggest one yet....15" OAL, 10" cutting edge, 3/16th 1095. Also pictured are the ironwood burl scales it will eventually have along with nickel silver bolster/guard.
fighter.jpg


Here it is pre-HT. I wanted to ask two questions:

1. I will be normalizing 3X to relieve stresses. I will be clay coating this one, going for a popping, wavy hamon. How much quenchant do you reccommed for a blade this size? Prior, I use probably a gallon or so veggie at 130 degrees. I am concerned the large size will overheat a small quench tank.

2. During the clay coat, do you apply the clay and HT with it wet, or let it dry first? My prior clay attempts did not follow my clay....

3. Clay: Do you full quench, relying on the clay to keep the spine cool, or do you apply clay and edge quench up to the bottom of the clay?
 
I would use at least 2-3 gallons of fast quench for that big boy.120-130 degrees.Coat the spine with clay and let dry overnight.Full quench (horizontal or vertical),all at once.An interrupted quench with 1095 can cause some annoying things to happen.1095 has to get in the oil fast,and cool down fast.You only have a second or two to do it in.Have everything ready,in place,and do a couple of test quenches to get the motion down pat (this is a good way to warm up your oil with a piece of scrap steel).
 
just going to give my humble opinion here (which differs from the norm).

I use satanite to clay-coat and I put it on right before it goes in the forge-furnace for heat-treating.

When I do it this way, it works every time.

If I let it dry first, then try it - I get cracking and separation. Even if I let it dry more than 10-15 minutes.

If I just put it straight into the forge, it will pop off once it is up to heat.


By "forge-furnace", what I mean is this = a 3" square tube inserted into the forge (cut to length) used just for heat-treating purposes. Can't say enough good about it. Much better heat control.

I've tried the other ways, including letting it dry for 4 days. I get better results with the method mentioned above, and I don't have to wait for it to dry. No cracks, no need for wire.


I am quenching in Brownells Tough Quench, in a horizontal tank. But I will be testing a vertical tank of tranny fluid soon.
 
The 3" square tube is an interesting idea....how do you lay the blade in it? use some sort of holder?

I applied it last night and tried to cure overnight with a huge halogen beating on it....its very hard but I do see a few cracks that im worried will allow weird cooling effects when I full quench with the clay.....maybe ill match those right before HT and hope for the best....this is a big experiment....

This will also push the length of my forge. I will easilly be able to get the whole blade in, but may need to keep it moving to get even heating...

With the newness of clay coating, a blade 3" longer than my next biggest....i am giving myself a 50% chance of sucess without total failure.....id rather expect the worst!
 
Satanite can pop off easily if just tossed in the forge, and cause warpage during quench, but it also cracks when it dries over time. I usually apply it after normalizing, and slowly heat it up a bit, moving it in and out of the forge to dry slowly so nothing pops off. It also helps if you use a torch to heat up the metal a little before adding the satanite as it helps it stick and dries it from the bottom-up.

There are a ton of ways to do it, you can do a full-quench, but you might get some "sori" (curvature and good) and possible cracking (not good), especially if you've got the blade pretty thin. You can counter that by thinning the coating on the spine a bit. Another way to do it is to leave the spine uncoated, and do an edge quench. You just need to make sure that your blade is fully heated (take it in and out of the forge many times so the tip doesn't overheat and the blade gets brought up to heat as a whole, and not in "parts." When you quench, just make sure your clay line is in the oil and the heat from the spine will slowly creep into your hamon and possibly create some ashi into your main hamon line. Just don't have too much of the steel sticking out because too much can pull the temper from the edge.

I hope this made a little sense -- experiment and play around, that is what makes it so much fun. You don't always have to use water, Mr. Fogg uses a slower quench and look at his hamons. :eek: :D
 
I need to make a "bracket" to do it right....:rolleyes:....but until then, I lay on against one side at a slight angle (60-75 degrees) and flip it.

Despite having a one-burner forge - I get even heat across and entire knife up to around 9 inches long. If I "keep it moving" I can heat up to a 12" blade (which is as much as I'll need for now).
 
Burchtree said:
Another way to do it is to leave the spine uncoated, and do an edge quench.......When you quench, just make sure your clay line is in the oil and the heat from the spine will slowly creep into your hamon and possibly create some ashi into your main hamon line.
Click to expand...

Oops...forgot to comment on this part - I do the same as you, Burch. Edge quench enough to cover the oil, uncoated spine.

I have found that the ole "dunk it in oil after it turns black" trick quickly diminishes a quench line. So, I let it air cool.
 
Thanks, guys!

I may try this one without the pipe just because ive never done that before and im already doing too many "new" things and want to minimise ignorance during the process.

I heated the blade, then applied 1/8-3/16ths of satinite in a weird patter on the top 2/3 of the spine. I did leave the spine coated, as I had not read this thread yet!

Overnight I pointed a halogen lamp at it all night, which kept the entire blade nice and hot so hopefully I got nice even drying over that 12 hour period. I did notice a few cracks that I may torch-seal tonight before HT.

My forge is big enough I can heat all at once, but I will be doing a lot of in and out to make sure the entire blade stays even. I sometimes have overheating problems directly below the burner inlet. where the heat "bounces" off the far side of the forge wall.

I have always edge quenched for my hamons, so I will do my normal HT process and edge quench up to the bottom of my clay, and let the spine cool in air while the blade remains in oil rather than dunking the whole thing.

Im crossing my fingers. If i get out of this without a crack, ill be happy. if i get out of it without an uncorrectable warp, I will be very happy. If i get out of this a fixable warp or good blade with the hamon I want, I will be thrilled!
 
I may be all wet, but I think you're going about this with the wrong approach TikTock.

The clay is not what creates the line.

What creates the hamon is the times and temperatures that are going on in the steel and the quenchant.

The clay does not keep the top of the blade from getting hot. It all gets hot. The clay builds up the thickness, thus increasing the thermal mass of the spine, and consequently not allowing it to cool at such a fast rate as the edge... and not allow it to get hard.

If you paint on patterns, hoping to get that in your steel, I think you'll be dissapointed.

The clay certainly does have an affect on the details of the line, but it's not as easy as just painting it on with the clay. That's what I thought when I first got into clay, and so do most people... it wasn't until after I finally got this through my thick skull that I started getting CLOSER to the results I wanted.

You'll be better off spending time researching time and temp affects, and then adjusting that for the clay :)

Or so I think :)

-Nick-
 
good point Nick -- the clay won't do nothing if you're not watching your temps.
 
I wanted to add, I'm CERTAINLY NOT disagreeing with the previous advice, as it's all good! :) Burch knows all the same crap I do :D

I just wanted to add that about the time and temp affect vs. trying to do it all with clay. With 1095, W1, and W2, you can get some smoke'n hamons without ANY clay once you nail the temps.

I'd imagine other steels as well, but those 3 are the three that I personally have done it with.

Also, NICE blade!

For future reference, I recommend you stop grinding at 60X and then just debur the edges (that's what I do). You'll find that it's very typical to have to re-heat-treat a blade while learning the clay process. No need to spend a bunch of time doing finish work that's going to get ground over :eek: :)

Post a pic when you get it done! :D
 
I will readily admit being a relative "new guy" in the world of heat-treating, etc. I am still learning...I can't pull any numbers off the top of my head and have to look up everything, almost every time I go heat-treat.


I do agree that you can get a nice quench line with no clay whatsoever.

Example: http://www.kosterknives.com/Ulu2.jpg
(unpolished, as-forged, as-quenched 5160 steel)

But you can certainly "paint" your quench line. Maybe you won't be able to spell your name in it...but I had no problem making these "waves" on a couple dozen knives:

http://www.kosterknives.com/maplesantoku.jpg
(1095, clay-coated, heated to 1450-1500, edge quenched - over the clay)



I know I don't I understand the process 100% (mostly because I am still learning the finer details of metallurgy) but from my observation, I've noticed the following:

  • The edge, spine and the clay do appear to be uniform in color during the "soak" time (ie. they all seem "orange" inside the forge-furnace).
  • The clay often "pops off" when quenching, yet there is still a hamon on these knives - just like the others.
  • If you dunk the full blade, even after letting it cool to black, bye-bye hamon.
  • Tempering affects the quality of the hamon line.
  • The spine side of the knife seems to stay hotter longer than a regular edge quench (as long as the clay stays on).

So, like I said, I don't understand all the "why's" concerning clay-coated quenching. But it's hard to argue with visible results.


Nick - you already know this, but I'll mention again that your knives have fantastic hamon lines. :thumbup:


TikTok - I imagine there's much more to this and we've only begun to touch the surface.



And...Good tip on the 60-grit pre-HT finish.
 
I'm going to back up my man Nick. Hamons are determined by time and temperature, definitely not the clay.

It took me a long time and many, many failed attempts to figure out that I could paint a Picasso on the blade and still end up with a straight hamon.

My best advice is to omit the clay entirely. Stick with hardening lines for the time being and figure out when the blade goes into solution, what temperature, time, and type of quench. Once you have a strong understanding of how ht'ing actually works, then move on to the clay. Otherwise, you'll be disappointed every time and will not make the leaps and bounds of improvement.

I try with each new knife to be Yoshihara, it hasn't happened for me yet, and probably won't for a very long time :). Hamon is a difficult, up hill battle; you'll also need to learn polishing and etching. Once you get hamons nailed I think you'll be like me and shudder when people refer to "hardening lines" as "hamons" :) ;) :p :cool:. That's tongue in cheek, but when I think of all the hard work, experiments, failed attempts, and frustration I see a difference between "hamon" and "hardening line" :) and you will too.

Good luck, and keep us posted, you'll nail it. I think the blade you've got there rocks, and the ironwood is fantastic!

Matt
 
could you elaborate on the difference, Matt?
 
Here is what I usually get from hamons with no clay...for reference:

Heating the oil now.....ill remember that I'm moving the heat, then keeping it there as the clay retains its heat and the edge is hardening in that split second.....whew!

Thanks again!!!!!!!



hamon.jpg

hamon.jpg

1.jpg
 
Lookin GOOOD.....

Heres my humble setup courtesy of Indian George!
setup.jpg


Here is the blade, pre HT. Satnite coated. No idea what I was doing with the clay...this is a big experiment.

before.jpg


HT went smooth. Got it just below critical and soaked to get the clay evenly glowing and hot. I had my GF monitoring 3 gallons of veggie for 130 degrees. Quench was as fast as possible in my new quenh tank, a 3.75 gallon planter....nice and long which made an edge quench easy. Got somegood flames on the clay itself as it eventually popped off. I was amazed how long that spine glowed with the clay. I held it edge deep in the oil "slicing" until the spine wouldnt leach heat and ruin temper.

Not one bit of warping at all...puuuurfect.

Here it is just out of the oil! Can I tell anything from this? I dunno....
after.jpg

Another...
after2.jpg
 
looking good so far.

it may be the lighting...is that a straight quench line showing toward the last few "waves"?

Sometimes, you can accidentally multi-quench these things...

Anyway, hand sand it 600 and etch and let us know!
 
I have posted this trick I learned from Fred Rowe before but thought I would share it again.Coat the blade with borax during normalization.It reduces decarb and makes the clay stick very very well.I have had no clay popping off since.
 
Im thinkin it was just lighting...espescially by THIS set of pics! 200 grit, etch, and I see multiple levels of lines in each arch, and the exact hamon I wanted! I am beyond psyched.....

Awwww yeahhhh:jerkit:

The dark line along the spine is just my rough hand sanding while wearing a glove out of temper#1.....

Lemmie know what you think!
1.jpg

2.jpg

3.jpg
 
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