Patina and cutting performance

T

tkill

Joined
Jul 19, 2013
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I'm new to the CV steel and patina game, and I made an observation this morning. I have a Case CV Peanut that I have been carrying daily for the past week or two. First of all I love this little knife. Most of my knife use is cutting up fruit and opening packages. Although yesterday I did use it to do some minor bush pruning while doing my yard work. I have been watching the patina progress on the knife, and I have made the following observation: It seems like as it develops the patina, and in the areas of the blade where the patina is developing, the blade isn't as smooth, almost a little bit tacky. Has anyone else ever noticed that and does it hurt the cutting performance?

My care for the blade has pretty much consisted of just using it and wiping it off after each use. I haven't oiled it since first buying it. I did clean it up with water and dish soap a couple of times.

 
Patina is oxidation and it dissolves tiny amounts of steel to occur. So yes, for a mirror finished blade patina will make it rougher. The difference is slight though, less than the difference between mirror and satin finish, so I don't believe it affects cutting performance at all. At some point though the patina gets down on the edge and I suppose would injure a polished edge slightly.
 
MarkPinTx said:
Patina is oxidation and it dissolves tiny amounts of steel to occur. So yes, for a mirror finished blade patina will make it rougher. The difference is slight though, less than the difference between mirror and satin finish, so I don't believe it affects cutting performance at all. At some point though the patina gets down on the edge and I suppose would injure a polished edge slightly.
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Which should clean up when sharpened again. :D
 
The short-winded answer - I've never worried about it. Keep it sharp, use it regularly.
 
My best-slicing blade is also the only one on which I've forced a patina (Schrade 8OT's clip blade). This is to say, the patina doesn't have to impact cutting performance at all. It can, but doesn't need to. The reason why, with my particular example, is that the edge on the blade has been more thinly-ground and gently convexed, and my daily stropping keeps about 15-20% of the blade's width, closest to the edge, highly polished. Slices like a laserbeam, and the patinated steel rarely, if ever, touches anything I cut with it. All of the friction with material being cut takes place on the polished convex shoulders (and that's why I like polished convexes the best, in the first place). :)


David
 
Smithhammer said:
The short-winded answer - I've never worried about it. Keep it sharp, use it regularly.
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jackknife said:
This^^^:thumbup::thumbup:
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HwangJino said:
A sharpening should fix that.

patina made my knife super shiny....
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The best kitchen knife I have is an Old Hickory, only a couple years old, with a thick patina. Takes a wicked edge. I've used it on everything.

Once I got over my initial fears of getting my blades dirty, I have had a good time since. I still need to try a apple cider vinegar patina on my barlow. My father wants to see what will happen to my barlow, and has told me to get to it!
 
Obsessed with Edges said:
All of the friction with material being cut takes place on the polished convex shoulders (and that's why I like polished convexes the best, in the first place). :)
David
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That's a good point. I'm still learning how to sharpen too, so I'll just continue to work on it a little every day... that should keep the cutting surface of the blade nice and shiny as well.
 
While I love 1095, I have noticed that CV takes what I would call a "pretty" patina. I like it a lot!
 
On my blades with a patina I still perform basic maintenance. Rinse off and dry blades, lightly oil joints on occasion and rub some of the oil onto the blade. Sharpen and strop as needed to keep a clean and sharp edge. Doesn't take much once you get a good edge on it once.

I try to rinse off just the blades and avoid getting water into the joints, unless they've gotten grungy from use, in which case I will rinse off the entire knife with hot water and dishwashing liquid, and then dry it thoroughly afterwards.

I like WD-40 Silicone spray after washing and drying the knife. It seems to provide decent lubrication while not leaving much residue, which can easily be wiped off leaving a thin silicone coating on the blades. And the WD-40 component of it still works as a water displacer for any remaining water in the joint.
 
The dark grey patina is pretty hard, you can polish it to a very smooth surface.
I forced a heavy patina on D2, rubbed it well with a kitchen pad: gave a low sheen, solid, dark grey patina. Yours is nowhere near this stage.
I didn't use a Brillo pad, I used one of the skinny green pads that look like Algae.
 
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