Case/Thomas Raindrop Damascus question

[Stich2442]

I have been using my Damascus Stag Peanut for a month now, light duty cutting dates, apples, bananas, mostly fruit with the clip blade, some packages and twine with the pen blade. The last two weeks I've noticed the contrast of the pattern becoming dull, has this happened to anyone else? I sort of expected the contrast to become greater with use as the carbon darkened with use and nickel would stay shiny. Any input is welcomed.

Pen blade looks fine

Top of exposed clip worn from pocket carry

Tip still has some contrast

Base of blade grey on grey

Thanks in advance,
Pete

 

[Groove]

It can re-etch at any time. Don't worry, use that little sucker! I have the SBJ in damascus and it's some sweet blade stock.

 

[Gevonovich]

I believe it has to do with differential exposure to atmospheric oxygen mainly though moisture. Since the Damascus steel is made of multiple layers of contrasting steels, many factors enter into the equation. What type metals where used, the carbon content of the metals used, what inhibitors were used on the blade to inhibit oxidation, how the sections of the blade are being exposed to acids of various types, how deep the etch and the variation in the depth of the etch.
I know just about nothing on this subject but it sure makes for some interesting reading. Thanks Pete and don't listen to me...lol

 

[Obsessed with Edges]

The damascus was originally etched (patina'd, in essence) with an acid, maybe a fairly strong one to make it extra dark. Any other acids will alter that, same as in how a patina will constantly change with exposure to fruits, etc., on any other carbon-bladed knife. I think the only damascus blades that don't change, are ones that never get used for such tasks.

Polishing the blade with Flitz/Simichrome/etc. will also scrub the oxide off. The 'pattern' will still be there, but much more subtle.

(Edit: I've noticed that the really, really dark patinas usually don't last too long anyway, if the blade is used, cleaned or polished much at all. The real heavy, dark layer of oxide that's created by acid exposure is usually very weakly bonded to the steel. Cleaning, polishing or brief exposure to other acids like fruits will remove a lot of the real dark stuff, leaving only the more strongly bonded layer directly in contact with the steel. That thinner layer will look much lighter by comparison.)


David

 

[Stich2442]

David I was thinking through use the pattern would get darker, more contrast between the nickel & the carbon, all my carbon blades are fairly dark, the reaction I seem to be having is as if I was using the knife to carve hard wood and the patina wore off.

Pete

Should I just expect it to be in a state of flux like all carbon blades, sometimes black, sometimes grey?

 

[Obsessed with Edges]

David I was thinking through use the pattern would get darker, more contrast between the nickel & the carbon, all my carbon blades are fairly dark, the reaction I seem to be having is as if I was using the knife to carve hard wood and the patina wore off.

Pete

I think while you were posting this reply, I was editing my earlier one. I've noticed, in forcing a patina on some of my own knives, the really dark stuff doesn't hold on very well. Comes off pretty easily, leaving a thinner and lighter, but more strongly bonded layer of (grey) oxide underneath.

The clip blade on my Schrade 8OT was virtually black after the last 'forced' patina on it, using a hot water/vinegar mix. Some light cleaning afterwards, with baking soda, scrubbed most of the real black stuff off.


David

 

[Stich2442]

I'm hoping as I use it, it will develop some more contrast. I don't care if it will change from time to time as all my knives are users, I just don't want to loose the contrast permanently. I have not seen any other Damascus blades on the forum lose contrast but possible they are not being used.

Pete

 

[Obsessed with Edges]

(...)Should I just expect it to be in a state of flux like all carbon blades, sometimes black, sometimes grey?

If using the knife, that's exactly what I would expect. I view that as a good thing; the 'character' changes with different experiences/uses, just as with most other things.


David

 

[Obsessed with Edges]

Damascus can always be re-etched to very dark, if one really wants to do so. I haven't done it myself, but it seems many have. I'd bookmarked these two threads a while back, as they look informative:

http://www.bladeforums.com/forums/showthread.php/516504-Damascus-Bring-out-the-pattern

http://www.bladeforums.com/forums/showthread.php/170118-Etching-Damascus


David

 

[Stich2442]

Thanks for the input David, makes sense, my blades are always changing sometimes black, sometimes a dull grey depending on what I'm doing, I'll post some pics in a few days.
This is what if looked like on Friday

And the beginning of the week

Today

Pete

 

[TLARbb]

I think what you are seeing is consistent with what you are cutting and the service the knife is in. If I have read correctly, most of the use has been in non-acid, non-corrosive environments and in a more abrasive type application. Abrasion will wear away some of the surface oxidation of the steel, thus lightening the contrast of the steels. You don't really have any worries there as it appears that you have properly cared for the blade steel. I have seen some damascus that, from a distancee, didn't look like damascus at all, until you look closely at the steel. At this point, I only have one Case damascus knife, my single blade sowbelly. Since it hasn't been used very much at all, it still looks new. As one would expect.


Ed J

 

[RobbW]

Birchwood Casey Gun Blue really brings out the contrast on my Raindrop Damascus peanut.

The thing about patina is that it's dynamic in the sense that it changes and changes color over time. What you cut, the liquids/juice/misture you expose it to will change it. Meat might make it grey, strawberries might make it blue. It won't stay that way if you use it.

But yeah, Birchwood will make the steel really dark grey-black. You can even blue the edge if you like. If you don't like that look, just strop, sharpen or polish the edge and it will get shiney again.

 

[Stich2442]

Thanks for the replies everyone, I've been using carbon steel knives for 34 year at work & play, this is my first damascus, I guess I was just surprised how easily the original etch faded. If I was carving with it I would expect some fade, but didn't really expect it cutting dates, apples, bananas, I would have expected it to pick up more of a patina.

Thanks,
Pete