CBN or Diamond Paste

[cwillett]

I'm re-visiting a question I posted a while back, but in more specific, modified form. Nano cloth is back in stock and I'm thinking of putting an order in for the new Makoto SG2 210mm wa gyuto. For a compound to go on the nanocloth, it seems that 0.5 micron would be the best choice. This would be following up 1 micron diamond paste on a balsa strop and replacing a bare bovine strop (not sure where the bovine strop would fit in). So, CBN spray or Richmond diamond spray. Although the is a 3x price different, neither is especially expensive ($45 vs $15). What to get?

[jacko9]

I can't compare since I haven't tried the Richmond diamond spray but, I do use 0.75 micron CBN and it works great. I use it on cherry wood blocks that I cut in my shop and plane smooth. If I nick it up a few shavings with my finish hand plane and I have a perfect surface again.

[Robstreperous]

Don't know if this matters to you but the CBN is water soluble --- which means you could use it along with a JNAT or synthetic stone. I use it on my JNats. I don't think the diamond paste can be used that way --- although I might be wrong about that.

[gladius]

The paste appears to also be water based.

[Robstreperous]

The paste appears to also be water based.

Thanks for that. Never let me be accused of knowingly sewing the seeds of disinformation!

[gladius]

It's apparently quite good...Gopher likes it...

I bought this product several months ago, and have stropped many knives with it on balsa.. and it works extremely well!I have tried the Diamond/CBN sprays, but keep returning to Richmond's paste. It cuts well according to the carbon/metal left beind on the strops.(I'm not sure if this link will work or not...).This link is to a forum post I put up, and commented on the paste there as well. The picture says it all! http://www.chefknivestogoforum.com/view ... =2&t=12021

[Bob Z]

Links would be great here for us noobs!

[gladius]

Links would be great here for us noobs!

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https://www.chefknivestogo.com/diamondpaste.html

https://www.chefknivestogo.com/strops.html

[ken123]

Links would be great here for us noobs!

https://www.chefknivestogo.com/cbnsprays.html

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Ken

[cwillett]

I ended up getting the nano cloth and the RIchmond spray. We'll see what I can do with it and possibly add another strop with a finer CBN in the future.

[ken123]

I have not used this spray on waterstones. While it may be water soluble, that doesn't exclude components that may still stain a waterstone. Emulsions and even pastes which usually have staining components can be complex formulations. Caveat emptor. If someone has data on this, let us know.

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Ken

[Chefcallari]

I'm re-visiting a question I posted a while back, but in more specific, modified form. Nano cloth is back in stock and I'm thinking of putting an order in for the new Makoto SG2 210mm wa gyuto. For a compound to go on the nanocloth, it seems that 0.5 micron would be the best choice. This would be following up 1 micron diamond paste on a balsa strop and replacing a bare bovine strop (not sure where the bovine strop would fit in). So, CBN spray or Richmond diamond spray. Although the is a 3x price different, neither is especially expensive ($45 vs $15). What to get?

I own the Richmond diamond past and the CKTG diamond paste.
I do not own the CBN.

First... The CKTG diamond paste is absolutely, unequivocally dogshit! I spoke to mark about this so.i don't feel bad about saying it.
It does absolutely nothing... Just gray toothpaste on a syringe.
The Richmond diamond paste is fucking amazing! I have 3,1 and .5 micron.
I know ken says CBN cuts better in "high speed applications" but i cant see paying the $30.extra for something that is technically a softer abrasive you know?

[cwillett]

First... The CKTG diamond paste is absolutely, unequivocally dogshit! I spoke to mark about this so.i don't feel bad about saying it.
It does absolutely nothing... Just gray toothpaste on a syringe.

Hmm...the 1 micron diamond paste seems to work pretty well for me. Last week I used it to polish up the blade road on a couple of knives and use it weekly to maintain edges.

I'm going to try out the 0.5 micron spray tonight. I coated the nanocloth strop earlier in the day and am letting it dry before trying it out for the first time.

[ken123]

"I know ken says CBN cuts better in "high speed applications" but i cant see paying the $30.extra for something that is technically a softer abrasive you know?"

Well this brings up another interesting discussion!

There is far more to this than just CBN vs diamond and even more to consider concerning paste vs emulsions and sprays.

CBN or cubic boron nitride is the second hardest abrasive next to diamond. How hard is that? Well it is harder than any of the carbides in the steels being sharpened - vanadium, niobium, chromium etc, so in most instances, it will more than exceed the need. It is harder than boron carbide and certainly harder than most of the abrasives found in waterstones, yet most sharpeners are satisfied with using waterstones. Indeed, when CBN is added to a natural or synthetic waterstone slurry, it greatly enhances the capabilities of the stone. It is more than sufficient.

Diamonds - well there are multiple forms of diamonds, monocrystalline and polycrystalline to name a few. Lapping plates and most competitive products use monocrystalline. Obviously monocrystalline diamond is composed of single crystals, poly is composed of a cluster of crystals. Clusters have far more sharp edges than mono. Because of this they cut far faster, more uniformly and hold their edge longer. They are more expensive than mono by far but for very abrasion resistant surfaces they outperform everything else. I have a much more extensive supply of poly diamond (and mono) overlapping most of the grits of CBN and have friable diamond grits as coarse as 200 microns. If you are sharpening ceramic knives, these are the ticket. If you are doing steel knives up to CPM 10v or REx121 (12% vanadium) CBN is the cheaper better solution. If you wish to get poly diamond abrasive - just give me a call. I have over 200 compounds available

That CBN works well in applications involving heat is well known but not an overly relevant criteria. Because diamond is similar to the carbon in steel, there are studies suggesting CBN over diamond to not affect the carbon levels in the steel. For high speed applications this is relevant, but not at all for bench stropping applications. You see this more in certerless high speed grinding applications. What I mention above is why you would select CBN over other alternatives.

So let's discuss what these particles are in - the substrate. There are sprays. emulsions and pastes. Not all are the same. My sprays are basically deionized water. These work quite nicely for finer particles, but empirically as you meet or exceed 2 microns, the particles quickly settle to the bottom of the container. Finer particles settle much more slowly and depending on the spray, also agglomerate (stick together) less with deionized water. This relates to electrostatic forces and so forth (another topic).

Emulsions are more of a creamy formulation and hold the particles in suspension better - so much so that I stopped carrying sprays past 4 microns and just use emulsions. My emulsions are tested for water solubility AND not staining either synthetic or natural stones. They also stick to strops very well - both bench strops and leather or linen belts used on grinders and disc sanders. The only things that have even greater adhesion to strops like high speed buffers are diamond bars (another topic).

I do carry pastes - both diamond (mono and poly) and CBN. Many pastes are NOT completely water soluble. Mine are not, BUT they hold reasonably well on leather belt grinders . I consider them a legacy application - some folks like them so I carry them. They have the side effect of attracting airborne particles more easily.

Another issue to consider is spreadability. My emulsions spread easily. No dragging it around with tools to spread it - it just spreads easily and dries quickly to a uniform surface. I consider it an optimal formulation. This is also some of what you pay for. A LOT of R&D went into this.

Yet another issue is duration of effect. CBN will outlast all but poly diamond in terms of usefulness. I have customers who have used my CBN on strops on belt grinders, getting an estimated usage of over 5,000 knives per 2 oz bottle! I know of no other system that competes with this. Consider the result when pricing a product.

Particle size is also a critical factor. If your 1 micron paste has particles coarser and finer than 1 micron, well the effect is different. This is determined on ALL of my products which are tested using PSD (particle size distribution) analyses, yielding THE most uniform products on the market. This shows in uniformity of scratch patterns on the steel with less stray scratching etc etc.

I could go on, but I've probably already put half of you to sleep, so I'll come up for air for a while

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Ken

[old onion]

Very good write up Ken. I found all that pretty darn interesting.I like knowing the science behind the different abrasives.

[ken123]

http://precisesharpening.blogspot.com/2 ... g.html?m=1

http://precisesharpening.blogspot.com/2 ... r.html?m=1

Here's a bit more 'homework if' you are interested ...

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Ken

[Chefcallari]

God i love when ken gets going!
Thank you for explaining that in such detail ken

[Chefcallari]

First... The CKTG diamond paste is absolutely, unequivocally dogshit! I spoke to mark about this so.i don't feel bad about saying it.
It does absolutely nothing... Just gray toothpaste on a syringe.

Hmm...the 1 micron diamond paste seems to work pretty well for me. Last week I used it to polish up the blade road on a couple of knives and use it weekly to maintain edges.

I'm going to try out the 0.5 micron spray tonight. I coated the nanocloth strop earlier in the day and am letting it dry before trying it out for the first time.

Hey if it works for you great! I can literally drag white #2 steel across my strops (balsa and leather... Both from CKTG) for hours and not see any cutting happen... Like no steel removal on the strop, no change in the edge.

Mark said the CKTG.paste is from china and the RICHMOND paste is from NYC Diamond district and has a much higher concentration of diamonds.