polishing a clay hardened knife blade

[NickWheeler]

Hey guys- I shared this on another forum and thought it might give some folks here an idea or two. It's certainly not the only way to do this, it's just what works for me.

This is the final polishing for a clay hardened W2 blade... it's all about TRYING to get the hamon and all its little intricacies to show.

It all starts with hand sanding, stones, etc. I come off the disc sander and start hand sanding at 320X work up to 500X, then 800X, then 1200X, then 1500X, then 2000X, and finally 2500X. Of course you go in one direction with one grit, and then cross over it with the next grit to ensure you remove ALL of the previous scratches.








Here it is at a super clean 2500. ANY scratches that are coarser than 2500 will show.... so you're just wasting your time if you don't get them all out first.

[NickWheeler]

Now traditionally the Japanese DO NOT etch their blades... it's something we do in modern times with modern steels. Many guys use Ferric Chloride, but I save that for damascus. I prefer to etch these blades with either lemon juice or vinegar. This one will be etched with vinegar cut with some dish soap. It's heated up (I've changed from simply heating the bowl in the microwave to keeping it on a hot plate on the bench while doing this).

The blade is CLEANED CLEANED CLEANED... then the etching starts by soaking a blue shop towel in the vinegar and constantly rubbing it over the blade for 10 minutes.



Here it is after 10 minutes... all oxidized and ugly. One step backward! But the hamon is starting to show more.



Here is the bench set-up for "oxide removal!" lol



The initial step for me is going over the blade with Liquid Flitz and a cotton make-up pad (I focus more on the soft part of the blade than the hard part, but I do go over the entire blade).

[NickWheeler]

It's a lot of repetitive work... etch, polish...etch, polish.... Each progressive etch brings out a little more detail.


Etch....AGAIN...lol


After 6 to 12 (give or take) etch/polish cycles, then I REALLY go after the fine detail in the hamon. I have a crude little handle I put to use (squished pipe with some 1/4-20 bolts in it) that allows me to really get ahold of the blade, but also move it around very easily.


I made this little block to mimic my thumb and reduce the chances of getting cut.


Here are some things I've accumulated for this job over the years. The 1500X powder (mixed with oil to make a slurry) will cut a lot finer than the 2500X paper did. Sometimes I mix it in oil, sometimes in the diamond compound lube... I don't know why LOL

[NickWheeler]

Polishing away! This little wood set-up is a purpose built tool. Very simple but very handy. It has a rubber pad on it, so I can poke the tip of the knife into it and polish....but easily move the blade to where it's easier to see what I'm doing.





It eventually comes down to just my thumb anyway, so I can FEEL how the abrasive slurry is cutting and if it needs more oil or abrasive added. NOTE!!! You should position your hand so that your fingers will "catch" on the spine of the blade so you don't slice your thumb open. My hand position here is WRONG!!! I had no choice though because my other thumb was bandaged due to a "to the bone" cut (from something non-related).



Man, this is a lot of tedious work! lol

[NickWheeler]

So after all of that (several days worth of work) where did it get us?

This is the result. Unfortunately you can't capture all of the "stuff" in a static photograph, but you can get a hint at what this looks like.

I fell in love with this type of stuff and have been pursuing both creating it in the first place (heat-treat) and also the polish to bring it out for about 7 or 8 years now.









Here is the finished knife. Photo by Jim Cooper, leather by MASTER craftsman Paul Long.





Thanks for looking folks... hopefully this helps somebody out or is at least kind of interesting to someone. :)

[Tim McCoy]

Great info - hey, does anyone else think that this would make a acceptable BP??

[Swamptroll]

Great info - hey, does anyone else think that this would make a acceptable BP??

It would make a great blueprint

[golgotha forge & anvil]

What a beautiful finished product!!! I too like the hamon in a blade. The info in ur post is fantastic and I'm sure extremely time consuming. Could u possibly post some details on where u acquired ur sanding paste, etc.? Many thanks for a great and informative article!!!

Gene

[Dave W]

Nick, what a finsh, it's really brought the activity alive!. Can I ask a question, when progressing through your various hand sanding grits do you use a lubricant or sand dry?. I've got a project blade to finish it's currently at 600 grit (done dry) and has had a light etch to outline the hamon activity and I'm curious if you continue with or without a lubricant.

[NickWheeler]

Okay, what the heck is a bp? Is it really blue print? Man, I'm showing my ignorance!!! LOL (nothing unusual about that! )


Thank you for the kind words and questions!

I don't mind sharing anything I can. I always want it to be clear that anything I do is certainly not the only way to do something and there are probably BETTER ways I just don't know about.

With that said- The polishing abrasives USE to be very easy to find. There's a place called Mager Scientific that sold abrasive powders for polishing lenses and such. I had purchased several grits for like $10 a pound. Now they don't have the stuff I bought, and what they do have is insanely expensive. Places like McMasterCarr sells the stuff, but again.... something like $120 a pound!!!

So enter ebay. There is a place on there that I got the 1500X Silicon Carbide powder from for about $12 shipped. I was hesitant to use something from a fireworks supply place and not some kind of lab... but it has proven to be very high quality (I had nightmares of going along with it and dragging a piece of gravel across my blade, but no such thing has happened ).

When I am sanding my blades I like to use WD-40. I have been making knives since I was 14 (32 now) and even had a full time stint of it for 5 years... I always thought fancy/unusual must be better, so I tried everything under the sun: water, soaps, KoolMist, Windex, Simple Green, cutting oils.... thinking something "more exotic" than WD-40 would be better.... but I am back to using WD-40 these days.

I DO add a few drops of this stuff called Ballistol though. It's a gun cleaning/lubricant/protectant and I LOVE it. You can get it many places online. It seems to help to avoid the oil and grit "gunking up" so quick and needing to be wiped off after two seconds.

Well, that was sure long-winded! Hope it helps!

Thanks guys :)