What to do with 6 micron diamond paste?

[miggus]

OK, weird question, I admit.

I started stropping and decided to skip CrOx and go directly to diamond stuff. The idea was that this would work with all steels and some people say diamond leaves a grittier finish, which sounds good for kitchen knives. I think this highlights weaknesses in my sharpening: there is a large jump in edge quality when I add a stropping stage after finishing (usually 4000 grit SC or Belgian Blue). So I assume burr removal is what is most important for me, not high polish.

I looked into it and most people seem to recommend 0.5 - 3 microns for kitchen knife stropping. That's what I use (1 strop with 1my and 1 strop with 3).

So now I got the paste with 6microns in the set, too, and am wondering if I can put that to use as well. I assume this is too coarse to use it for genuine stropping, but it might be useful for touch-ups, I thought. Or is there another use case for a 6 micron strop?

(I cut veggies only, so I don't need a super polished edge).

 

[Bear]

I go all the way up to 12µ for stropping, 6µ is my favorite but I do want to try 9µ. The only problem is that you need a lot of strops.
It's not that weird of a question.

 

[Ruso]

Based on some chart, 6micron is roughly 2000JIS. If you finish on 4K or 5K JIS stropping on 6micron paste should create a coarser edge compared to what you have achieved with the stones. Which does not make much sense to me. If you want to strop on 6micron, you should stop at around 1or2K.
This are just my thoughts, I do not have any data to back it up. I would love to hear if anybody has some data or personal experience with this.

 

[Bear]

Just paste up a piece of denim or better yet balsam, tell us what you think, its not the same as sharpening on a stone.

 

[Rangen]

I have not noticed stropping on diamond appreciably changing the apparent toothiness in an an edge. I think of it as more a cleanup operation, getting bits of burr off. Generally I use 8 micron for Western soft steel knives, 4 micron for the good stuff. Diamond on a wood or leather surface is tons less aggressive than diamond on a metal plate.

For pasted strops, I like to use basswood, sanded flat, glued to an acrylic base to prevent warping. 8x3 basswood can be found at hobby shops, and I found the 8x3 acrylic on the big auction site. Basswood doesn't deform like denim or leather, and wears less quickly under the pressure of a knife than balsa, which I use for razor stropping but not for knives.

For completeness sake, I should mention that I don't use these strops much lately, preferring to build by deburring skills on stones, and reaching for one of the wonderful strops I got on BST from someone here who used to make and sell them, when I didn't fully succeed on the stones.

 

[William Hunt]

I like to use a 1 micron diamond strop for touching up or refreshing the edge. At some point the process no longer works and it’s time to pull out the stones. I’ve read that you can use a 6 micron strop instead of pulling the stones out but no idea if it works. Should be worth a shot if you already have some.

 

[Blank Blades.]

Ive been wanting to try some courser compounds for a while. Ive always used 1 micron, i also have a .5 micron but for whatever reason i seem to like 1 micron more.

 

[miggus]

@jwthaparc I'd be haöpy to learn how your expermiments go if you try it out

 

[gc0220]

As far as x y or z being grittier than a b c; People say a lot of things in knife land. Almost none of it can be taken seriously because it's almost always subjective or recived mythology rather than empirical. I could entertain the idea but I'd like to see some evidence before I just accept it.

I can tell you what I might use something like that for. I might use that on wood for certain pocket knives. I might also use that to touch up kitchen knives made of steels like hap40. I'd probably not use it on something like white or blue steel which deburs super easy and abrades very easily too. too aggressive for that. At least for my uses, I touch up my carbon knives every single time I pick them up and I do so with very fine abrasives.

Another thing to consider with compounds is concentration. It makes an appreciable difference. There is such a thing as too much of a good thing. A heavy dose of high concentration at that kind of grit would be some serious business for stropping. A decent use for such a thing would be to help fully remove the burr on certain annoying alloy steels. Another thing to consider is the surface choice. It also depends how much you're stropping and how you're stropping. Ideally you don't want too high or too little concentration, you want to strop enough but not too much, and properly, with proper pressure and proper control over the angles of contact. If all I had access to in the known universe was that particular compound, I could make it work in a variety of situations just based on how I was using it.

But all of this depends on nuanced details like how you use and maintain your knives. Not everyone uses things the same way. Some people let their knives get super dull between any kind of maintenance, other people almost obsessively touch them up after every single minor use and everything in between. It details like that which seem to be commonly overlooked when answering various questions.

I've never tried anything quite that course on a straight razor so I can't comment there but aside from edges, this stuff would come in handy for polishing various things, various metal or other surfaces.

 

[miggus]

Great reply! Thank you for your detailed answer @gc0220 !

Good point about the hearsay in the knife scene. Science of sharp has a number of good articles on stropping with electron microscope pics. His focus is more on razors though, the conclusions are different sometimes. This is probably the most evidence-based info there is on the topic

The Pasted Strop – part 4

The most striking observation that can be made of this series of images is that, with the exception of the coarsest (15 micron) diamond abrasive, the amount of micro-convexity produced is insensitive to the abrasive size. There is greater apex damage with the coarsest abrasives, but not an increase in micro-convexity.

Consistent with the earlier observation with the inexpensive diamond paste, the 15 micron diamond sprayed strop produced no micro-convexity. Apex uniformity decreases with the coarsest abrasives, but at much smaller scale than the abrasive size. There is no unevenness or “micro-serrations” resulting from scratches of depth comparable to the grit size.

None of the diamond sprays produced an increase in near-apex angle as large as is typically observed with the various metal polishes.

Yeah I use carbons mostly, thought 6 micron stropping might replace high grit stones for touch ups.
Besides some SG2 knives, I regularly sharpen Western stainless knives for people. Could be helpful as a finisher / for deburring there as well, I'm going to experiment a bit.