Scuff marks on the face of the knife?

[abechang23]

Hello everyone,

I'm not really sure what to call these marks that I have on some of my knives - they're not necessarily scratches, but they kind of look like scuff marks that appear on the face of the knife after I sharpen. Obviously, I feel I am doing something incorrectly and I suspect these marks are there from where my finger makes contact with the knife as I sharpen and the microscopic abrasive material on my fingers is leaving these marks. Is that a correct assessment?

Anyway, it doesn't really affect the performance of my knives but I feel like it's a pretty tell-tale sign of someone who might not be the best sharpener in the world. Does anyone have any experience with dealing with this? How would I go about removing these marks and what steps do you guys take to avoid them in the first place?

I use shapton pro splash and go's and my fingertips on my non-dominant hand always have some residue on them once I start going. I feel like I have a pretty decent understanding of how to sharpen my knives and I've been doing my own work for years now but I can't really seem to shake this habit.

Thanks for the help guys.

[d_rap]

First, it's going to be difficult if not impossible to diagnose scuff marks accurately without some sharp photos. That will help people make suggestions about fixes as well.

But, assuming that it is happening during sharpening there are only a couple of possibilities. Probably most of us here have, at one time or another on our sharpening journey, held a knife too low, at too acute an angle, and scuffed the face of the blade on the stone. So there's that, but I'm assuming from your post that you are fairly certain that's not what happened, and, yes, that would be more like scratches, obviously.

So yes, abrasive material from the stone, especially a coarse stone, combined with metal residue or swarf can scuff a blade face, particularly if the cladding is very soft (and the swarf is from the harder core steel, naturally). And in my experience, the relative fragility of blade faces varies by knife. My Shibata AS for example, a favorite of mine, takes scratches and scuffs fairly easily.

It can be from abrasive material on your fingers, or you might inadvertently rub abrasive around with even a very clean towel as you dry during sharpening. Laying the blade down where the face can contact he surface and moving it even slightly if there is any residue on the face is another potential issue. The list goes on.

The best fix is awareness. Sharpen at the sink (either with a bridge, or just next to the sink on the counter, as I do) and rinse well, frequently as you work, and keep your towels scrupulously clean. Things like that. And with the stones, frequently you want slurry, but if you're worried about scuffs on a particular job, rinse the stone frequently to minimize slurry.

Ultimately there is just no way to absolutely avoid the phenomenon you are talking about but you can certainly make it so that usually there are not noticeable scuffs. Sharpening raises a slurry (varies by grit and stone) and that slurry can't possibly be kept entirely off the blade face unless you go to the trouble of masking off everything but the edge with tape (some Edge Pro users do that, since they lay their knives on a surface that loads up easily). But tape just isn't practical most of the time, it causes it's own problems, and virtually no one, certainly not pros, ever use it. So I think you can get better at rinsing, drying and being aware of slurry, but you can't eliminate the issue. Any experienced person or attentive user is going to be able to tell when a knife has been sharpened especially if you look at it closely enough at the right angle in good light.

Rust erasers, compounds, polishing--I'll leave that all to people who know more about it.

[abechang23]

First, it's going to be difficult if not impossible to diagnose scuff marks accurately without some sharp photos. That will help people make suggestions about fixes as well.

But, assuming that it is happening during sharpening there are only a couple of possibilities. Probably most of us here have, at one time or another on our sharpening journey, held a knife too low, at too acute an angle, and scuffed the face of the blade on the stone. So there's that, but I'm assuming from your post that you are fairly certain that's not what happened, and, yes, that would be more like scratches, obviously.

So yes, abrasive material from the stone, especially a coarse stone, combined with metal residue or swarf can scuff a blade face, particularly if the cladding is very soft (and the swarf is from the harder core steel, naturally). And in my experience, the relative fragility of blade faces varies by knife. My Shibata AS for example, a favorite of mine, takes scratches and scuffs fairly easily.

It can be from abrasive material on your fingers, or you might inadvertently rub abrasive around with even a very clean towel as you dry during sharpening. Laying the blade down where the face can contact he surface and moving it even slightly if there is any residue on the face is another potential issue. The list goes on.

The best fix is awareness. Sharpen at the sink (either with a bridge, or just next to the sink on the counter, as I do) and rinse well, frequently as you work, and keep your towels scrupulously clean. Things like that. And with the stones, frequently you want slurry, but if you're worried about scuffs on a particular job, rinse the stone frequently to minimize slurry.

Ultimately there is just no way to absolutely avoid the phenomenon you are talking about but you can certainly make it so that usually there are not noticeable scuffs. Sharpening raises a slurry (varies by grit and stone) and that slurry can't possibly be kept entirely off the blade face unless you go to the trouble of masking off everything but the edge with tape (some Edge Pro users do that, since they lay their knives on a surface that loads up easily). But tape just isn't practical most of the time, it causes it's own problems, and virtually no one, certainly not pros, ever use it. So I think you can get better at rinsing, drying and being aware of slurry, but you can't eliminate the issue. Any experienced person or attentive user is going to be able to tell when a knife has been sharpened especially if you look at it closely enough at the right angle in good light.

Rust erasers, compounds, polishing--I'll leave that all to people who know more about it.

Thank you very much for the informative post. Good call about the abrasive material left behind on the towel - that's not even something I was thinking about but it makes perfect sense.

I will attach some photos so everyone can get a clear idea of what I'm talking about.

The above photo are the scuff marks I'm referring to. The other side of my knife is relatively clean as you can see from the below image.

Given the placement of where the scuff marks are and the direction they're going in, I'm 99% sure it's from my fingers because the scuffs are located where my fingers usually press when I'm sharpening.

The knife above is a Kiritsuke AS 240mm, stainless cladding with an Aogami Super core. I've had it for a few years now and it's in the regular rotation at work.

If anyone has experience with removing these marks, I would be very grateful. I will also be extra careful in the future to make sure my hands and towel are as clean as possible. It might be time to invest in a sink bridge so I can have immediate access to running water. Like I said, I use Shapton Pro splash and go's and I generally give the stones a little rinse after each use. It's pretty quick to build up a light slurry after a few minutes so I don't find it necessary to go out of my way to make one.

[d_rap]

You're welcome.

You may be right, but just another possibility: the angle of the scuffs is so symmetrical, and in spots extends so clearly almost to the edge, that I think you have to suspect a couple of light errant strokes during sharpening or even stropping, depending on what you use. Maybe even more pics would help, different angles and light, but it may be too much consistency for a slurry-filled index finger or a swipe with a towel. Especially if you're sharpening lengthwise at an angle to the stone, longways, as most sharpeners do with long knives (Mark in his videos, for example) and it looks like you are, then those strokes might also be where you went a little low. And they look like they were very light strokes at high grit, but they're just so consistent with angular sharpening strokes. Zoom in on your first shot. Look at how some of those marks go all the way to the very edge.

Not sure, but just something to consider. Spit-balling here. You may well be right, particularly if you slide your fingers all the way down and up at that angle rather than just pushing straight down. But do you? If anything, most people push straight down an inch or so above the edge and slide their fingers laterally along the blade to address different parts of the edge.

[abechang23]

You're welcome.

You may be right, but just another possibility: the angle of the scuffs is so symmetrical, and in spots extends so clearly almost to the edge, that I think you have to suspect a couple of light errant strokes during sharpening or even stropping, depending on what you use. Maybe even more pics would help, different angles and light, but it may be too much consistency for a slurry-filled index finger or a swipe with a towel. Especially if you're sharpening lengthwise at an angle to the stone, longways, as most sharpeners do with long knives (Mark in his videos, for example) and it looks like you are, then those strokes might also be where you went a little low. And they look like they were very light strokes at high grit, but they're just so consistent with angular sharpening strokes. Zoom in on your first shot. Look at how some of those marks go all the way to the very edge.

Not sure, but just something to consider. Spit-balling here. You may well be right, particularly if you slide your fingers all the way down and up at that angle rather than just pushing straight down. But do you? If anything, most people push straight down an inch or so above the edge and slide their fingers laterally along the blade to address different parts of the edge.

I actually do place my fingers very close to the edge - in fact, sometimes the bottom part of my fingertip makes contact with the stone. I find that placing my fingers so low helps me keep control of the angle better - if my fingers are higher up, like an inch above the edge, I find that I tend to slightly wobble as I stroke away from me. The reason the other side of the knife doesn't have the same scuff marks is because when I sharpen the side with the scuff marks on them, I place the knife with the edge facing away from me and I stroke toward me - in this case, my fingers aren't really touching the face of the knife at all and I kind of support the spine. The marks go up like almost 1/3 of the way on the knife face - I just don't see myself dropping the knife low enough for the marks to go that high up if they're from stone contact.

The marks are just so consistent with where I place my fingers, even the angle of them is how my fingers are oriented on the blade during sharpening. There is a tiny chance the face made contact with the stone, but I really am not sure if that's the case. To give you more information, I've never had to sharpen this particular knife on anything lower than 1k grit - I generally just keep it well maintained and most of the time, I only touch it up on the 5k. I do not do any stropping as I'm unsure how much of a functional difference that makes.

I'm not trying to argue and say you're 100% wrong by the way - I'm just giving you as much info as I can. The fact that the marks are there at all is proof enough that I'm doing something wrong so I'm by no means defending my process. Maybe I should get used to placing my fingers higher up on the knife - I find that my fingertips get covered in slurry and I have to scrub them pretty thoroughly to get the dark stains off my hands so I'm guessing my hand placement is just not ideal at all.

Thanks for taking the time to help. If anyone has experience with removing these marks, I would appreciate it and hopefully I can take what I learned here and prevent this mistake from happening again.

[taz575]

To me, those look like scuffs from a high grit stone when the blade angle dips too low and it hits the stone as you are sharpening. The stainless cladding is often very soft. I would get some non woven abrasive pads (ScotchBrite) in a range of grits. Lay the blade on the pad and use a stropping motion straight down the pad, spine first. Work your way up the grits and it will help establish an even satin finish back to the blade and help hide/blend those scuffs in and re establish a satin finish on the blade where the scratch lines go straight from spine to edge.

You can get a maroon color pad at a hardware/home depot type of store and amazon has them in finer grits as well. The green may be too coarse and leave deeper scratches. I would look for a set with maroon, grey and white pads as these are normally a good range for a kitchen knife. You can also use sandpaper on a soft backer (mousepad, thick felt, leather, etc) to get the same results by working up to the grit you want.

If you have your hands on a thin, flexible blades and use too much pressure when sharpening, you could potentially flex the blade enough to make contact with the stone in some areas. Fillet knives are a PITA to sharpen when they are super flexible!

[abechang23]

To me, those look like scuffs from a high grit stone when the blade angle dips too low and it hits the stone as you are sharpening. The stainless cladding is often very soft. I would get some non woven abrasive pads (ScotchBrite) in a range of grits. Lay the blade on the pad and use a stropping motion straight down the pad, spine first. Work your way up the grits and it will help establish an even satin finish back to the blade and help hide/blend those scuffs in and re establish a satin finish on the blade where the scratch lines go straight from spine to edge.

You can get a maroon color pad at a hardware/home depot type of store and amazon has them in finer grits as well. The green may be too coarse and leave deeper scratches. I would look for a set with maroon, grey and white pads as these are normally a good range for a kitchen knife. You can also use sandpaper on a soft backer (mousepad, thick felt, leather, etc) to get the same results by working up to the grit you want.

If you have your hands on a thin, flexible blades and use too much pressure when sharpening, you could potentially flex the blade enough to make contact with the stone in some areas. Fillet knives are a PITA to sharpen when they are super flexible!

Thank you very much for sharing your knowledge. I think at this point my best option is to just leave the marks alone. To be perfectly honest, I'm not 100% sure of how to do the cleaning process you mentioned and I don't want to risk scratching or screwing up the knife any further. Since the scuffs don't really have a negative impact on the knife's functionality, I guess I'll just look at it like part of the patina - just something that naturally occurred when I was still dialing in my sharpening skills.

I just don't have the confidence I can fully execute the process you're describing properly since I've never done it before. I'll just be more careful going forward. Thanks again.

[Bensbites]

I skimmed over the comments, if I missed any details I apologize. Have you tried any of the following?
Mothers metal polish
Flitz polish
Or a magic eraser

I am wondering if the markings are so close to the surface, that polishing compounds micro abrasives will help?

[abechang23]

I skimmed over the comments, if I missed any details I apologize. Have you tried any of the following?
Mothers metal polish
Flitz polish
Or a magic eraser

I am wondering if the markings are so close to the surface, that polishing compounds micro abrasives will help?

These are very good suggestions. I have not tried any of these methods, and I will order some of these things and give it a try. Thank you very much.

[ken123]

For allowing Bensbites' recommendation I would use diamond bars for this application. I would start at 4 microns.

Ken

[abechang23]

For allowing Bensbites' recommendation I would use diamond bars for this application. I would start at 4 microns.

Ken

Thank you for the suggestion - to give you an indication of my level of ignorance, I have no idea what you're saying. I think I know what a diamond bar is, but I'm not sure what 4 microns is or how to apply it.

[ken123]

_

Contact me directly for more details.

Ken

[Kalaeb]

Omg, Ken, I love you, but you got to stop recommending the buffer to everyone. This is a bad idea and should only be used in very capable hands. Ken is a pro and can use it well. Please DO NOT use the buffer to remover surface scratches if you are new to knives.

[d_rap]

Yeah, agree with Kalaeb, hopefully abechang, just use that video to see what the diamond bars are. They are polishing paste where the key abrasive is diamond particles.

Microns are the particle grit size. Like a stone is 3K but that has a corresponding micron measurement too, which in the end is more accurate.

[ken123]

I do appreciate that this buffer can be a bit dangerous in less experienced or overconfident hands including my own hands, so I have another option - a smaller buffer. This buffer is variable speed from 0-7000 rpm and uses smaller buffing wheels. I use this on razors to refinish razor surfaces and knives with more safety.



Ken

[orezeno]

Omg, Ken, I love you, but you got to stop recommending the buffer to everyone. This is a bad idea and should only be used in very capable hands. Ken is a pro and can use it well. Please DO NOT use the buffer to remover surface scratches if you are new to knives.

I remember seeing this video years ago when I was considering getting the Diamond Bar for the shop. You're right to advise caution. And even in this video, around the 2:34-2:35 you can see the buffer grab the knife. As an experienced user, Ken reacts immediately.

I also think that refinishing the OP's knife is overkill. The aesthetics don't impair function and continued use of the knife will add more "personality" to its finish anyway.

If the OP thinks swarf on the fingers is marking up the knife, try adjusting technique with a beater knife until the problem is resolved.

[ken123]

Overkill? Perhaps so. It may just be my ocd coming out I would do it but that's just me.

Here's a trick. Run the blade along the length of the buffer rather than perpendicular to the spinning buff. This significantly lessens the risk of the buff grabbing the blade and allows for more pressure being applied.

If you haven't done anything yet send me your knife and I'll do it if you cover shipping. It will be a 'teaching case'

Ken

[Tostadas]

I've had success refinishing with high grit sandpaper. The scuffs you show do not look to be deep, so I'd try something like 1500-2500grit, and using the sandpaper in one direction to maintain the aesthetics

[taz575]

I will try to do a video showing how to "strop" the blade on the non woven abrasive pads tomorrow or Friday.

[ken123]

Overkill? Perhaps so. It may just be my ocd coming out I would do it but that's just me.

Here's a trick. Run the blade along the length of the buffer rather than perpendicular to the spinning buff. This significantly lessens the risk of the buff grabbing the blade and allows for more pressure being applied.

If you haven't done anything yet send me your knife and I'll do it if you cover shipping. It will be a 'teaching case'

Ken

So I did this video perhaps to reduce bufferphobia and also to demonstrate the technique I specified.

A quick and easy way to remove patina and rust from a Spyderco edc


Ken