View Full Version : Satinite for temper line

05-22-2003, 12:16 PM
I'm using Satinite to clay coat a blade prior heat treat. I am hoping to get a strong temper line. I understand that it dries very slowly. Can anyone tell me how long this should be allowed to dry before HT. I've applied it about 1/8 inch thick. Any other tips would be appreciated.

Mark Van Loon
05-22-2003, 10:09 PM
i usually let mine dry for 24 hours. you may notice some fine cracking in the clay the next day, just make a little more but mix it VERY runny and apply to the cracked areas with a small paintbrush. this will seal off the cracks. just dont use too much water or you can wash some of your application away

05-26-2003, 08:31 AM
Well I coated my blades with satenite then heat treated and everything seemed to work out ok until I cleaned up the blades and discovered significant pitting in the area of the blade which was under the satenite. Anyone else ever have this problem or know what may have happened.:mad: I had a nice 400 grit finish going into the heat treat just like on all my blades. The portion of the blade not covered by satenite was covered with brownells PBC.

Mark Van Loon
05-26-2003, 10:42 PM
hmmmm.....never had that happen to me before, if you could post a pic of the pitting it may help for some to see the result.

05-26-2003, 11:32 PM
Mark, the pitting is gone but it took some serious hand sanding to do it. Obviously it wasn't real deep. The only thing I can think of is maybe there were some cracks or air bubbles in the satinite. I'll have to pay close attention to my application next time and see if it happens again. If I get a repeat problem I'll post some pics.

Jerry Hossom
05-27-2003, 07:44 AM
I don't do this, but here are some thoughts on the pitting. If the blade wasn't completely clean before coating that could cause very localized separation of the satinite. Also, if there were any air bubbles, even very tiny ones, in the satinite, they will be trapped when it dries and expand during heating to cause localized cracking. You might want to mix the satinite with distilled water and mix slowly to avoid introducing air.

Just some thoughts...

05-27-2003, 10:25 AM
Thanks Jerry, I'll apply your suggestions on my next try.

05-31-2003, 08:51 AM
Hey Fred,

After using ApGreen #36 for a couple of years getting turned on to Satinite has produced an epiphany for this tyype of heattreat...for me at least. The Ap Green would crack like crazy and you had to keep patching it up, and if you fired it after say an hour or two it would plump up and throw off the whole thermal equation causing the hamon to drift away from the clay edge toward the blade edge. The hamon developement suffered and looked pretty crappy at times. It also likes to blow off prematurely (no pun intended LOL) during the quench if it wasn't wired on... and I hate having to use wire. Then came Satinite and now to address what you had experienced.

I leave the blades rather thick before heattreat. I used to leave them at an 80 grit finish to hold the clay on. Now I leave them at 36 grit...and it seems to hold the clay alot better. Pitting then is not an issue because I'm doing say 10-15% of my grinding after heattreat. I've never tried to heattreat anything, stainless inculded, higher than 220 for that reason (fear of pitting). Oh, I let the Satinite dry for about an hour and it doesn't expand AT ALL and the hamon develops right where you want it...well.. pretty much anyway.

I think Jerry is right too about THOUROUGHLY cleaning the blade before coating and don't get finger oils on it afterwards. Things will conspire against you quickly is this stlye of heattreat as I'm sure you know. Anyway let us know how the next round goes.

Take Care

05-31-2003, 11:12 AM
Hey Rob, thanks for the info. Do I understand you correctly that you let the satenite dry for only one hour and then heat treat? I understood that it was very slow drying so I let mine dry for a couple of days. Also how thick do you apply it. I'v got some orders to get out so I won't be experimenting for a week or so but I will check back with my next results.

05-31-2003, 01:17 PM
Yes Fred,
You understand correctly about the one hour or so.....guess I'm an impatient type.:) Its seems to work fine...

I'm putting up to 1/8ish in. on and the thickest portion is right on top of the line/hamon. This tapers slightly toward the spine. I grind these Japanese style blades kinda elongated diamond cross-section. My technique is evolving with each blade as I find that with the little quirks and mistakes each time, I'm actually learning from them, at least the ones I can remember long enough, and this particular feature is from my most recent and most successful blade to date. So I'm not speaking from a real wealth of experience here...except that I've done A BUNCH of bad/mediocre blades of this type. (Hmmmm. Maybe its because I wouldn't let the paint dry :confused: )

You might want to pick up a copy of the Yoshido Yoshihara book entitled The Craft of the Japanese Sword. Definitely not a how-to book but there are a number of semi-technical aspects to glean and there are many useful insights into some of the subleties of heatreat and finish. Besides its a classic. BTW, if you've never checked out Don Fogg's website DO SO 'cuz its packed with useful info on this.

Anyway, please share your results on the next batch!!
(Take good notes!)


Terry Primos
05-31-2003, 02:18 PM
This is going to sound like I'm off topic at first, but bear with me. I think I understand Fred's dilemma. The key words were Brownell's PBC. That's what I generally use for heat-treating as well. It is a non-scaling compound which allows you to take the blade down to pretty much the final dimensions before heat-treating. Since the oxygen is blocked out there's no pitting, decarb, etc. You don't have to leave any sacrificial steel.

I take mine down to a 400 grit hand-rubbed finish before heat-treating, as shown below:

Here's a shot of the blade after heat-treating. It's easy to see where the compound was not applied on the tang. From this point I temper, put on an edge and test the blade then go right to the final hand-rubbed finish without having to grind.

Anyway, what has this got to do with the Satanite? Well, when the blades come out this clean, you get real spoiled, real quick. A week or two ago, I tried the same thing that Fred is talking about. I coated the back with Satanite, then brought the blade up to about 560 degrees F. and melted the PBC compound over the rest of the blade, then took the steel on up to critical and quenched.

After heat-treating, the areas covered with PBC were clean and smooth, but some of the areas covered with Satanite had some pitting that had to be dealt with. That makes you hold your breath and clamp your butt cheeks together real tight when cleaning it up because the blade is already at what is supposed to be pretty much the final dimensions.

The next time I use clay, I will leave the blade a little thicker. Oh, I had my clay about 1/8" thick like Rob said. I let it dry over night, and there were no cracks.


The last time PBC compound was discussed, I got a ton of email about it. My email time is very limited these days. If you want to know more about it, you can read my tutorial: Scale Prevention During Heat Treating ( You can also strike up a new thread here on the forums. Oh, and no, you can't use the PBC compound on high alloy steels. It is only effective up to somewhere around 1600 - 1650 degress F.

05-31-2003, 03:04 PM
Terry, I did mine the exact way you described. The pitting was not deep and I was able to clean it up by hand. But it is a real bummer to see that pitting after working the blades to a 400 grit finish before heat treat. By the way I got the PBC tip from your tutorial and love it.

What do you think would happen if....
1. Work the blade to a 400 grit finish.
2. heat to 560 (or so).
3. Coat entire blade with PBC
4. let cool
5. Apply Satenite
6. Heat treat
Have you ever let a blade cool with PBC before bringing to critical?

Terry Primos
05-31-2003, 06:12 PM
I don't know if that would work. First off, I'm not sure if the Satanite would stick to the compound.

Also, once I tried preparing a few blades ahead of time and having them sitting on the bench, coated in the compound, and ready to go. It could have just been an off day, but the results didn't seem to be as good as melting the compound onto the blade and immediately taking it up to critical before the blade and compound cooled.

Heck, give it try and see what happens.

05-31-2003, 09:32 PM
Terry, (or anyone else), if using the PBC compound, can you still rely on the magnet test? In other words, does the PBC detract from or inhibit the ability of the magnet to work properly? Thanks, Bill.

05-31-2003, 10:05 PM
I'm sure Terry will be back to answer your question but I can tell you that you can still use the magnet as usual. No problem. Also, No Scale!

06-01-2003, 07:43 AM
Nice piece on the PBC application/use. Thanks!!

Fred, Here's the link to Don Fogg's website:


Terry Primos
06-01-2003, 10:14 AM
Thanks Rob, and welcome to the forums.

For those interested in this stuff, I think that it may be mentioned in the tutorial, but let me go ahead and mention here -- this does take a little practice and experimentation. It's not an automatic, no brainer, miracle.

It's pretty easy to learn to get an even coat on small blades like a 4" hunter, but is more challanging on something like a 8" - 12" Bowie, because you obviously have more area to cover before the piece gets too cool to melt the compound.

I've had mixed reviews from folks who heat-treat in a forge, but the general concensus is that it doesn't work well. I use a controlled heat-treating furnace / oven. It's much more difficult to maintain a constant controlled temp in the forge.

Let's see ... Oh yeah, I put a piece of stainless steel heat-treating foil in the bottom of my furnace to catch any of the compound that might drip off the blade. The compound is not too good for the firebrick.

I'm just trying to cover all the bases here. I don't want folks to try it and get uspet with me. You do have to "fiddle" with it and develop a system.

06-01-2003, 10:35 AM
I just wanted to add a tip or two regarding my own experience with PBC. I found that a cheese shaker is ideal for applying the PBC. It is like a salt shaker only larger with larger holes. Before application I mix it up a bit to break up any clumping due to the high Florida humidity. I bring the knife up to 560/580 and holding the blade over a newspaper, shake the powder liberally over both sides of the blade working quickly. I don't worry about the excess powder that doesn't hit the blade because I use the newspaper center fold as a chute to return the excess to the container. I am careful to ensure the entire blade is coated. Cleanup of the blade is with boiling water. Much of the cleanup results in the quench. I haven't experienced any pitting and no scale and the powder goes a long way.

I've been very happy with it. It allows me to work harder on other aspects of knifemaking.

06-01-2003, 02:17 PM
I had a terrible experience with the PBC compound, and think my comments are the thread Terry was speaking of. Pay very close heed to his recommendations for maximum temp, as if it gets even 25F higher the borax in the PBC will acidify and do really obnoxious things to the blade surface. Multiple cycles are even much worse, lemme tell ya. :) My first experience was a nitemare, and trashed a really nice ladder pattern bowie it ate so deep into the steel.

This caused me to buy a thermocouple and meter to test various areas in my HT furnace. I have learned the hard way that the temp you set on that furnace is not necessarily the temp you are getting at the blade. I have also learned that some furnace manufacturers think that temps within a hundred degrees of the setpoint are just fine to them, especially in the lower ranges of tempering. 50-100 degrees is perfectly acceptable to them in the ranges we austenize at. Turns out, you have to devlop your method based on repeat testing even when using a furnace, and you can't really trust formulaic numbers given out by HT data because of the variabilty in temp measurments and inaccuracies from furnace to furnace, pyrometer to pyrometer. Nowadays I have bored some holes in the furnace cover and firebrick so i can set a probe very close to the blade so I can be more aware of the temp. Even then, at those temps the precision of the measurment is only +/- 3% at best. Sad, but that old magnet is a better test in many ways than anything technology can bring to bear.

06-22-2003, 02:03 AM
Whatever you do Fred, don't listen to that Patton guy! :evil

HAAHAHAHA, just kidding. Rob always has whicked blades on his table and cares a heck of a lot about what goes into his work.

I like to put a very light wash of dilluted Satanite over the whole blade prior to applying the thick coat on the spine.

After that's fairly dry, I apply the patterned clay on the back, and let it dry. I'm like Rob, I get really impatient...BUT, when I am forced to let one dry out for a few days, I always feel I get a more active hamon. It seems to follow the clay more accurately if I really let it dry.

Personally, I don't think you're going to have much luck trying to do the clay thin with a finely finished blade...but don't think I'd want to dissuade you from trying!

Like Rob said, a rough finish seems to work very well for giving the clay something to bite. I like either a 50x grinder finish or a draw-filed surface.

Just something to gnaw on :)

06-27-2003, 08:21 AM
Nick, Nick, Nick,...........Don't make me come over there. Remember,

The Montana just..................a..............

few................ weeks..........................away.............:e vil :evil

:D :p :cool: :smokin

Can't wait to compare notes again. Lookin forward to seeing you.

Remind me to tell you about the Japanese style forging hammer I just made.


Jerry Hossom
06-27-2003, 11:59 AM
I completely agree with Nick with respect to Rob... :)

I don't know jack about this heating and beating stuff, but it's generally true if you want anything to stick to steel, rougher is better. Early on when working with CPM-3V, which takes an extremely fine finish, I had trouble getting my handle slabs to stay put. The steel on the tang would almost polish at 400 grit, and the epoxy didn't have anything to hang onto. I now routinely etch my tangs in 50% FeCl before epoxying on the handle. I don't know if it's worth a try but etching might also give the Satanite a little more grip, and maybe even allow a little finer finish before hardening.