Favorite abrasives and surfaces for paddle strops?

I have not done paddle strops for a few years now and wanted to see what types of abrasives and surfaces are in favor now days.

I was always a fan of diamond sprays myself after moving away from the soft pastes which seemed to never dry completely. I have always liked to use the sprays on smooth, skin side firm leather for my straight razors feeling that the rougher flesh side would be more likely to round an edge.

I know many of the knife guys like the CBN emulsions but didn't know if they were in favor with the straight razor crowd. For knives I stick with the hard, bar type abrasives applied to the rougher flesh side as it is easiest to apply to that surface and it just seems to hold on to the abrasive much better.

In my experience the harder or firmer the surface the more exact the edge with the least chance for any rounding. On knives I have favored a softer leather so as to impart a convexing of the edge for my outdoors woods knives.

So, what does everyone prefer now days and if using them on leather do you prefer the skin side or the rougher flesh side? What are your thoughts on balsa or even basswood ( harder than balsa) which was used on some vintage paddles?

A long time ago I got some cerium oxide for lens polishing, it is quite fine. I do not remember what the micron rating on it is. I like it a lot, although I seldom use it anymore. I tried it on hanging leather, hanging felt and then felt on a flexible paddle. I also tried CrOx on leather on a similar bench strop as well as TI’s fine paste. The cerium on the felt is the champ as far as I can see.

We've corresponded about this recently, so I'm sorry to repeat, but I'm glad that you're thinking to move back to paddles. I'm mostly interested in the Solingen green, red, and black crayons these days, applying these to the finish side of vegetable-tanned belting that has been garnet sanded to 180x to give the surface some tooth. For razors, I like to use such a surface pulled taut as a hanging strop, or on a bed of hard felt for some give on an otherwise solid-body paddle. For knives, balsa works for me, pasted the same way. To apply the paste, I rub it on my thumb, then rub the pasted thumb on the leather or balsa, never the crayon directly on the honing surface, apart from some initial scribble as needed. This is analogous to using chromium oxide and ferric oxide (red and black) pigments suspended in oil, which are applied in much the same way, the latter perhaps being preferable for balsa. All that said, I have been straight stropping recently on a small, thin solid wood paddle lined with shell cordovan. From my experience, both it and some of the smaller Solingen paddles, loom, foam-lined strops benefit from around three laterally biassed laps with a little pressure followed by a few more up-and-down laps lightening up and taking the blade in sections and returning to the laterally-biassed pass from time to time to even things out. Also, what has been curious to me is that there is one current and some otherwise vintage small pasted balsa paddle strops that have significant scoring lines following the length of the strop. I assume that this is to account for humidity fluctuations, as the balsa wood can otherwise heave and hoe like the sea. For my 3" x 12" x 1/4" balsa strops glued to plywood for kitchen knives, I scored the balsa surfaces lengthwise with an X-acto knife to minimize fluctuation from humidity changes. Seems to have helped and it's almost invisible apart from where swarf has collected and oxidized.

I've use Cr0X on Felt and diamond on Linen. As you said it can convex the edge, but I feel a little convexing is ok. Stropping does it too, just not as quickly. I made a paddle strop. I made it to use while honing then figured I'd use it for knives. If I only knew how to sharpen a knife. Ha. Getting there.

I use CBN and Diamond paste and sprays .50 to .10um. Chrome Oxide and Metal polish for tools and knives. Metal polish is too aggressive for razors but works well on knives and tools for a micro chipped edge.

I use paddles for tools and knives with scraped horse butt to an almost suede finish similar to Nakayama second strop. On the skin side it holds Diamond well, a scraped flesh side of veg tanned, to hold Chrome Oxide or metal polish and can be scraped off and re applied easily.

I also use MDF and Bamboo (cut from cutting board) pasted with metal polish on one side and Chrome Oxide the other for plane blades and chisels. No balsa, too soft.

My shop strop for razors is a vintage thick Certified, Russian diamond cut back, well oiled and rolled, soft and floppy like a well washed sock. I scraped the face and strop on both sides, plane leather. I also strop on Polyester Canvas sail cloth pasted with Chrome Oxide between stones when honing.

My daily drivers are a pair of Nakayama one vintage, one newer, with suede leather and linen second strops. I really like the linen and suede.

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Originally Posted by RezDog

A long time ago I got some cerium oxide for lens polishing, it is quite fine. I do not remember what the micron rating on it is. I like it a lot, although I seldom use it anymore. I tried it on hanging leather, hanging felt and then felt on a flexible paddle. I also tried CrOx on leather on a similar bench strop as well as TI’s fine paste. The cerium on the felt is the champ as far as I can see.

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Many sellers of Cerium Oxide do not list a micron rating. Some who do list size, quote ratings around 2-2.5 microns. However, I have seen some references to super cerium oxide that may be around 0.5 micron.

I use CrOX paste and diamond spray on balsa

I use CrOX and Diamond sprays on two felts that I have for mine. I got away from the crayons because I didn't feel I was getting an even application and was afraid of a mini lump or two messing up an edge.

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Originally Posted by Euclid440

I also use MDF and Bamboo (cut from cutting board) pasted with metal polish on one side and Chrome Oxide the other for plane blades and chisels. No balsa, too soft.

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Your experiences sound much like mine other than I have not tried CBN. I do wonder where balsa got its start. To me it holds paste well but just seemed too soft and easily dented. I have liked basswood as it is is much more dense and has a grain/pore structure that holds pastes well.

Like you I find the stick abrasives work best on rougher leather, anything softer on smooth leather or wood depending just how firm a surface is needed. Even for knives I have been using the back side of a skived/split tooling leather that is very thin and very hard that provides almost no give under normal stropping pressure unless I specifically want a convex then I go thicker and softer. Been playing with kangaroo as well since it is nearly paper thin, smooth yet with a little tooth to it and quite firm.


Thanks for you input


Tony

Lots of great info provided by everyone. I appreciate it. Much sounds similar to my experiences and maybe not much has changed over the years with paddle strops as it has with hones.....remember when a Norton 3K/8K was THE stone to have !

Oddly though I have not liked hard felt as much as it seems others have. I just feel it was a bit soft for my tastes and just never really got on with it.

For now I am working with a firm veg tanned tooling leather for razor paddles and both a hard smooth and a skived/split rough surface veg tanned tooling leather for my bench strops. This material, rather than the natural soft flesh side, has had the flesh side sliced off with a razor sharp knife leaving a hard, nearly sand paper feeling, open pore surface to hold stick type pastes (best for knives and tools).


Been fun experimenting and hearing what others are using.


Thanks,
Tony

For razors I use clean flax and horsehide. For knives I use a 3 x 3 x 12 balsa block. I have white, green and diamond spray as well as one side I glued a piece of veg tanned leather. Balsa is soft I agree. But it keeps you honest. It's easy to see if you are making mistakes. Plus it's easy enough to sand it flat if you dent it. Or if you decide to use some other paste.

I haven’t used pastes much lately for my razors and maybe I should. In the (not too distant) past I have used Kremer pigments (CrOx/FeOx) on balsa with great success. Also CBN on micro fiber cloth attached to a piece of thick glass.

Every time I use diamond I end up hating the edge so I have never really got that one down good.

I have been using CBN emulsion 0.25 micron on glass backed roo. It works very well for me. I've been thinking of adding another of these strops and pasting with CBN emulsion 0.125 micron.

I have a paddle strop with CrOx on balsa on one side and diamond spray on hard felt on the other. Tunes up an edge off a coticule quite nicely if I use the diamond on felt followed by CrOx on balsa. I know that sounds as if I might be walking the edge back using that order, but finishing on diamond leaves the edge a tad harsh IMHO.

I have found that CBN paste on basswood works quite well as long as the basswood is thick enough to avoid warping. I have also used CBN on kangaroo leather and on nanocloth. Either substrates is acceptable.

However, many of the strongest proponents of diamond pastes and sprays prefer balsa. Diamond is a much harsher abrasive than CBN both as diamond is a harder material and the shape of the diamond crystals makes it more aggressive. Balsa has a more open grain structure than basswood. Thus, the diamond crystals get embedded in the grain with only a portion of the diamonds being exposed. That reduces some of the harshness of the diamond abrasive.

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Originally Posted by RayClem

I have found that CBN paste on basswood works quite well as long as the basswood is thick enough to avoid warping. I have also used CBN on kangaroo leather and on nanocloth. Either substrates is acceptable.

However, many of the strongest proponents of diamond pastes and sprays prefer balsa. Diamond is a much harsher abrasive than CBN both as diamond is a harder material and the shape of the diamond crystals makes it more aggressive. Balsa has a more open grain structure than basswood. Thus, the diamond crystals get embedded in the grain with only a portion of the diamonds being exposed. That reduces some of the harshness of the diamond abrasive.

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Good points on the diamond. I myself always roll my diamond applied surfaces with a steel roller to try and embed them as deeply and securely as possible.

Interesting story of diamond abrasive harshness. Years ago I sold coticule stones and one of my customers was a rabbi who trained Shochets (kosher butchers). They have very strict rules on how an animal is killed for meat and the knife that is used. It must have a perfect edge, no nicks, scratches, flaws or imperfections. It is inspected both before the kill and immediately after. Any flaws found in either inspection and the meat cannot be called kosher. In our discussions of stones and sharpening the topic of diamond abrasives and stropping came up. He explained that he would not use diamond as the angular shape left microscopic scratches on the surface and would violate the Jewish law requiring a perfect edge. The coticule was allowed as the shape of the abrasive was not as harsh and did not leave what they considered scratches.

“Years ago I sold coticule stones and one of my customers was a rabbi who trained Shochets (kosher butchers). They have very strict rules on how an animal is killed for meat and the knife that is used. It must have a perfect edge, no nicks, scratches, flaws or imperfections. It is inspected both before the kill and immediately after. Any flaws found in either inspection and the meat cannot be called kosher.”

That may have been so, just a few years ago. That is not the case now.

There are now, many vendors for Sub Micron diamond paste and sprays, that leave no visible stria, at 400x, (.25 and .10um) rivaling the finish and edge of CBN. Many of these Diamond pastes are very affordable now $15-20 and readily available on the Bay and other sites. Though few razors can handle this edge at this level, but really for a razor one does not need that level to shave well.

It would be interesting to hear from one of the Rabbis who conducts the knife inspections, to see how and what they are looking for. I would also like to know their opinion of a CBN finish on a knife.

Euclid440 The traditional way for them to check is to run the finger nail along the entire edge and feeling for any flaws. While I doubt anyone can feel the difference between a coticule and diamond spray edge with their nail, the idea of it theoretically having scratches was enough for him to not allow their use whether or not they could be seen or felt.


I have long lost touch with him so cannot ask but am curious what their thoughts are now on this subject and whether the sub micron pastes or even CBN can be used. Tradition is a tough thing to break and he seemed very set on certain coticule stones. He tested every stone he bought for performance and inspected them under magnification before agreeing to purchase any. As I recall he had no interest in the Thüringen stones, whether modern or vintage. He taught Shochets from all over the country and would sell them the stones to be used.

I have heard that butchers used Coticules back in the day, but surprisingly it was the natural Belgian Blue side of the stone that they used to sharpen knives for cutting meat.

I have noticed after years of putting high grit edges on my wife’s kitchen knives 12 and 20K, the edges she prefers for meat is a toothy Diamond Plate edge 400-600. I finish her knives on a 1k Diamond plate now.

Vintage natural coticules did/do have some interesting and good performing BBW’s. I remember watching a tv show where a guy, a professional fisherman, was butchering a large fish, tuna or sword fish, and he was describing the process.

He reached in to a well and pulled out a large 8 or 10X3 inch coticule and slapped it on the motor cover, BBW side up and honed a large curved carbon steel filet knife, saying “This is the best stone for sharpening a knife for cutting fish”. Then tossing the stone back into the well with abandon when done. I cringed, thinking, and he’s not even using the best part of the stone.

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Originally Posted by Tony Miller

Euclid440 The traditional way for them to check is to run the finger nail along the entire edge and feeling for any flaws. While I doubt anyone can feel the difference between a coticule and diamond spray edge with their nail, the idea of it theoretically having scratches was enough for him to not allow their use whether or not they could be seen or felt.


I have long lost touch with him so cannot ask but am curious what their thoughts are now on this subject and whether the sub micron pastes or even CBN can be used. Tradition is a tough thing to break and he seemed very set on certain coticule stones. He tested every stone he bought for performance and inspected them under magnification before agreeing to purchase any. As I recall he had no interest in the Thüringen stones, whether modern or vintage. He taught Shochets from all over the country and would sell them the stones to be used.

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Any idea what is okay to use for lapping kosher coticules? I know there is a prohibition against using them with oil.

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Originally Posted by Brontosaurus

Any idea what is okay to use for lapping kosher coticules? I know there is a prohibition against using them with oil.

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I always used water on the ones I sold and lapped them on wet/dry paper stuck to a granite machinist surface plate.

I know CBN and diamond are all the rage but for razors I always liked Dovo(Herold) Red and TI White on a smooth leather strop. Loom or cushioned paddle preferred. The really fine "peach skin" leather is fine too. I find that it increases keenness by convexing the shoulders of the bevel also....as always YMMV.

The reason that imperfections or "serrations" are not allowed in schechita is to prevent tearing of the esophagus or trachea with would render it non-kosher.

I use formax white lightning compound on a flesh sided paddle strop. I do about twenty passes then about 40 passes on a clean flesh paddle strop that I sanded down with 2000 grit wet/dry sand paper then I go to the strop no linen. Whether im off the stone or just refreshing its the same routine...it works for me but that's just me...… I find it works better than any green paste ive used but ive never felt the need to try diamond (maybe I should) so....ther ya go!

Having tried them all, and still my personal favourite it would have to be Chromium Oxide on a linen strop.

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Originally Posted by celticcrusader

Having tried them all, and still my personal favourite it would have to be Chromium Oxide on a linen strop.

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On cloth or real flax linen? I tend to not put anything on real linen since the linen is already somewhat abrasive. Seems like whatever is on top will be doing the work and whatever is underneath will now just be covered up.

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Originally Posted by Tony Miller

On cloth or real flax linen? I tend to not put anything on real linen since the linen is already somewhat abrasive. Seems like whatever is on top will be doing the work and whatever is underneath will now just be covered up.

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That's correct Tony, I should have said flax linen, that's the only linen I have.

Interesting thread. I never really thought about what to use on a strop.

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Originally Posted by PatrickA51

Interesting thread. I never really thought about what to use on a strop.

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PatrickA51, This would be for strops specifically for honing/sharpening. I would not use anything on my daily strop. Every day stropping on any abrasive would be overkill in my opinion. That said, many knife guys make it a practice of doing a few passes on an abrasive strop any day they have actually used their blades. Wirth some knife steels that are very difficult to sharpen (like M4), keeping it sharp is key. With razors having such a delicate edge I feel it would be too much.