Damascus understanding

A

armstrong

Joined
Sep 25, 2015
Messages
9
I'm brand new to the knife making craft and to get some practice in I have been making (assembling) a few knives from pre-made blanks of different kinds. I don't intend to be an assembler, I just wanted to get a feel for the process before attempting to ruin some steel stock on the belt grinder. I've done two hidden and two full tang knives and going forward I will be only making from scratch. I have always liked the look of Damascus steel and am interested in making my own but wanted to get familiar with it before trying to make some. I bought a relatively inexpensive blank from one of the online retailers and started making a handle the other day. As part of the process I soldered the brass guard to the blank which turned out fine but left me with a fairly distinct rainbow effect on the blade from the heat of the torch. I wasn't applying the heat directly to the blade but it conducted its way up. My question is can the rainbow be removed from the blade and in the future am I better off with epoxy instead of solder? One last thing, when I received the blank the pattern was very light in one area, almost like it had been scuffed away, can I bring it back with acid etching?
 
Hi Armstrong,
Welcome to Bladeforums and knifemaking in general. Your questions would be better answered in the Shop Talk forum (perhaps a moderator can move this thread), but I'll take a quick shot at it myself. The rainbow effect is surface oxidation caused by the heat from the torch. It may have softened the steel slightly in the affected area (a localized tempering, of sorts) but as long as you did not overheat the cutting edge it should be fine. It can be removed by light sanding, but that will also affect the surface pattern of the damascus. Given the uneven finish you mentioned, I would simply refinish the entire blade. This will give you some good practice in hand sanding. It will be a bit tricky with the guard already attached, but not impossible. Once you have a nice, clean, uniform finish, you can re-etch the damascus in ferric chloride to bring out the pattern, and then clean it up with a high grit abrasive paste.

Soldering is a good way to attach a guard and if done well will produce a solid, airtight joint. That said, a lot of makers, including myself, prefer a tight, press fit guard sealed from the back with a bit of epoxy or JB weld.
 
Thanks Wulf, I couldn't have asked for a better reply. Excellent explanation that makes perfect sense to me. I'm guessing I should start with a 400 grit and work my way up to 1000 or 1500? Given the pattern and grain of the damascus, is there a particular direction to sand in?
 
I would start at 150, then work my way up to 400. I don't usually go much higher than that with damascus. Typically I will alternate sanding direction so that I finish with a clean and straight scratch pattern that runs more or less parallel with the cutting edge. For example I will sand to 150 parallel to the edge, then hit it with 240 grit paper going perpendicular until all the 150 grit scratches are gone, and then go to 400 parallel again until I get all the 240 grit scratches out. Once you've gone through a few etching / polishing cycles, you won't really see any of the 400 grit scratches anymore, just the damascus pattern underneath.

Here's a short video of a blade I polished out just a few days ago.
[video=youtube;tczumKjB2yQ]https://www.youtube.com/watch?v=tczumKjB2yQ&feature=youtu.be[/video]
It's a simple, low layer twist pattern that I brought up to a clean 400 grit finish, then gave 5 etching cycles, rubbing off the oxides with a high grit abrasive powder after each etch. The repeated deep etching and polishing cycles helped to enhance the pattern by creating a bit of surface topography that reflects light at varying angles to create a bit of shimmer, or "chatoyance."
 
Great info. I will follow these steps. Where did you pick up the Mittenwalder?

And "chatoyance" is now my new favorite word.
 
I live just a few kilometers away from the Mittenwalder brewery. I've become one of their most loyal customers. :)
 
I have never used the abrasive powder before, what's the process you use? By the way, I just looked at some photos of Mittenwald, what a beautiful town! My family is originally from Leipzig and some day I need to visit. I may have to add your town to my list.
 
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Some makers use pre-made pastes like simichrome or flitz. I've been using pulverized dolomite, known here in Germany as Wiener Kalk, that I mix with oil to create a light slurry. The powder is screened to something like 5 microns, which creates an extremely fine grit. I read somewhere that the particle size used in simichrome polish is 8-10 microns, which I believe is around 2000 grit, though I'm not exactly sure. Simichrome is readily available in the U.S. (check your local auto parts store) and would probably work quite well for what you're trying to do.

Let me also add that there are many different ways to etch and polish damascus. I have tried a few, and while this is the method I currently use, I certainly can't claim that it's the best. You may well find an entirely different method that suits your style and taste much better than mine.
 
Of course, but you've given me a good starting point. I see that various types of acid are used by different makers for various reasons. I guess it also depends on the type of steel and pattern, nevertheless I have a solid place to start.

Thanks a lot, or should I say vielen dank.
 
Wulf said:
Some makers use pre-made pastes like simichrome or flitz. I've been using pulverized dolomite, known here in Germany as Wiener Kalk, that I mix with oil to create a light slurry. The powder is screened to something like 5 microns, which creates an extremely fine grit. I read somewhere that the particle size used in simichrome polish is 8-10 microns, which I believe is around 2000 grit, though I'm not exactly sure. Simichrome is readily available in the U.S. (check your local auto parts store) and would probably work quite well for what you're trying to do.

Let me also add that there are many different ways to etch and polish damascus. I have tried a few, and while this is the method I currently use, I certainly can't claim that it's the best. You may well find an entirely different method that suits your style and taste much better than mine.
Click to expand...

Little bit of a necro-thread but I thought it was hilarious that there's a product called Weiner Kalk.

Back to mature conversations.
 
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