Non-diamond stropping compounds

[Mark76]

I am a bit dazzled about non-diamond stropping compounds. With diamond pastes and sprays you know what you get, since you know the material and the grit size is specified. (Although you don’t know yet how pure the stuff is.)

However, with non-diamond compounds it is often less clear. A local hardware store sells hards blocks of unspecified green stuff (well, it is labeled “fine” 🙂 ). They told me I should rub it on leather. I doubt that works, but even if it would, I don’t know how fine the stuff is.

It is confusing, because a lot of people say they work with “green paste” or “red paste”. Green paste often contains chromium oxide with a grit size of 0.5 micron (although I also encountered chromium oxide with a grit size of 3 microns :ohmy: ) and iron oxide is red. But for example Dovo makes “green paste” with a much larger grit size, while they also sell a (probably green) compound with chromium oxide. And their red paste does not contain any iron oxide.

In short: my head swims a bit. Who can enlighten me?

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Jende Industries]

Picture yourself standing at the very edge of the highest mountain cliff in the world – now take one step off the cliff.

With this questioning, you’re about to fall down the rabbit hole…. B)

The stuff from the hardware store is good for general purposes, although finding the specs on them may take some doing. Generally speaking, the size of the green and red rouges will be between 3 and 0.5 microns. There will be a range of grits in any product (noted as a +/-) Here is an excellent article that goes into particle distribution more.

On brand name compounds, like Hand American, the concentration of the average size is usually reported as the grit. So for the HA .5 chromium oxide, there is a major concentration of .5 particles, but there will also be range of 1 micron to .25 micron. Distribution curves apply to the WEPS diamond pastes and Ken Schwartz’s compounds as well.

Unnamed brands may not have the same spec requirements, as the 1st article shows. See part 2 of that article for more info.

Welcome to the Rabbit hole! 👿

[Kennith Chan]

In the old days I know some people used Jeweler’s rouge. Haven’t made a real search on the grit size. Since gold and silver is quite soft I think these might be quite fine?

[Mark76]

It definitely is a rabbit hole. I asked the question “what do you strop with and what is in it” at another knife forum. All sorts of different answers, green stuff, silver tuff, yellow compound, black paste, and one person answered he didn’t know since he was colour blind :D. One of the best known Dutch knife makers uses blue compound :S . But nobody was able to tell what it actually was, let alone explain why they used this particular material.

I guess that surprised me. But it must be me. There cannot be a 1000 ghost drivers 😉

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Kennith Chan]

Came across this site while reading, scroll down you will see a PDF with Grit comparisons. On there I think they have green compounds.

Grit Comparison-5-17-09.pdf

[Mark76]

Came across this site while reading, scroll down you will see a PDF with Grit comparisons. On there I think they have green compounds.

Grit Comparison-5-17-09.pdf

Thanks Monk! That is a useful one. There are actually at least two green compounds. Green rouge (rouge, shouldn’t rouge be red?) with 3 micron grit size and chromium oxide with a 0.5 micron grit size. It starts to make some sense…

I think I’ll register at Straightrazorplace, even though I don’t shave with a straight razor. There is a lot of very interesting material there!

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Mark76]

It is not my habit to answer my own questions (or maybe it is… I used to be an academic 😉 ), but I did some research on the internet this weekend.

A few things I found out that were new to me:

• Many stropping compounds don’t have a label, so you have no clue what is in there. But even if the stuff is labeled, that is no guarantee the stuff conforms to the specifications. See Tom’s post above and the link to the blog post he gave.
• I found a nice article treating most common stropping compounds. It also mentions some less common stropping methods with some background information, like why you would want to strop on a newspaper.
• The article doesn’t treat CBN (Cubic Boron Nitride), which is a non-diamond compound sold by Wicked Edge. But here you can find everything you always wanted to know about CBN.
• I forgot where I read it, but a nice method to make your own stropping compounds is to collect the slurry from your whetstones, put it on some paper and let it dry. The micron size of the particles in the compound should be equal to or less than that of the grit size of the stone.
• I read about people cleaning their WEPS using a vacuum cleaner. Maybe they could collect the iron particles from the cleaner bag. This would be somewhat abrasive itself already, but it’d be even nicer to let it rust. I am not a chemist and have no idea what you would end up with (there appear to be different types of iron oxide alone and their micron sizes may vary a lot), but iron oxide is a common abrasive 😆 .

I have a related question: during my search for stropping compounds I was offered 3M Diapad diamond stropping paste with micron sizes from 15 down to 0.25. Google confirms this stuff actually exists, but that is about all information I could find. Apparently this stuff is normally only used in industrial applications.

3M does make some good polishing products and Diapad is their brand name for hand pads/sanding blocks. Does anyone have more information on this compound?

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Kennith Chan]

Thanks for all the nice info Mark76. Something comes to mind as well. The Dry stones seem to chip pieces off the edge, whereas the waterstones seem to give a much smoother finish. This could be because it is using water as a lubricant and thus there is slightly less friction on the metal surface. Perhaps the liquid in the diamond pastes and others is not water and could be more oil based to help form the suspension. Maybe a slightly higher viscosity liquid to help keep the particles in suspension.

Not sure if the more experienced guys have used oil instead of water. Car engine oil comes to mind as that comes under alot of heat and friction. Not sure what that would do to the stones but on the wood and leather strops should be ok. Also Ceramics is used in some modified car engines so I think that could also be ok.

I would stick to the leather and some oil and see how that works. Maybe edible oil would be better for the kitchen knives and engine oil for the EDC/working knives. One can always wash the knives after the Oil strop with dishwashing soap.

[Marion]

The problem with cooking oils is that they will go rancid, petroleum based light machine oils and kerosene oils will become gummy with age, were as the industrial synthetic oils don’t, typically… As with all lubricants YMMV.

[Jende Industries]

Excellent finds, Mark! :woohoo:

You can actually get diamond papers down to 0.10 micron 🙂 Ken Schwartz has them for the edge pro, and I’m sure he can put them on the Wicked Edge. I’ve actually got the whole product line coming in the mail to me as we speak, but not on the WEPS.

Monk – good observations about the differences between the diamonds and whetstones. B)

While water does lubricate, that is only half the answer – the diamonds literally dig out trenches in the steel by scoring through it at “full depth”. IOW, since diamonds are very hard, they scratch through the metal leaving a more serrated edge, which can be seen as micro chipping – especially at the very coarse levels. Using the stones dry does leave the window open for metal flakes to cut into the edge, also causing chips.

The water stones work in two different ways – the water acts as a carrier for the lose abrasives to either be flushed off the stone (Shaptons work this way), or to be further utilized as the abrasive breaks down and mixes with the slurry, matrix, swarf and water, making a paste which leaves the edge more refined than the advertised grit (most other stones, including the WEPS ceramics).

Oil is the traditional carrier for holding the swarf. Arkansas stones, for example, excel when used with oil (you can use water, too, BTW) because oil tends to attract dirt and debris, which in this case is the metal swarf and stone particles.

:cheer:

[Mark76]

I just found an amazing article on the effects of stropping, with highly magnification photographs of edges.

Wonder photos..[/url]

…

From 1931!

Molecule Polishing: my blog about sharpening with the Wicked Edge

[wickededge]

I just found an amazing article on the effects of stropping, with highly magnification photographs of edges.

Wonder photos..[/url]

…

From 1931!

Great article, thank you for posting it! I really like this quote “Stropping a safety razor blade presents exactly the same theoretical problem as does a barber’s razor. The blade being in most cases only slightly thicker than a piece of paper, there is no shank to serve as a guide to the proper angle. The solution is to use a mechanical stropping device that will hold the blade at the proper angle.”

-Clay

[Mark76]

The solution is to use a mechanical stropping device that will hold the blade at the proper angle.”

😀

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Ken Schwartz]

“I forgot where I read it, but a nice method to make your own stropping compounds is to collect the slurry from your whetstones, put it on some paper and let it dry. The micron size of the particles in the compound should be equal to or less than that of the grit size of the stone.”

That would probably be me 🙂 I’ve been using stones, both natural and synthetic as a source of stropping compound for years, using paper originally and balsa later as a substrate. I harvest various forms of stone slurry, derrived from flattening or surface conditioning stones with diamond plates of various levels of fineness, typically from 120 to 1200 grit. In some instances, primarily with natural stones, I also harvest swarf produced from sharpening activity which includes both the metal slurry and the metal swarf. In some instances the metal swarf forms a useful component for example swarf from a clad knife. It is a dry technique and is quite useful.

Lately I’ve extended the technique to incorporating CBN, Diamond and most recently Alumina suspensions, all in a water soluble medium, in stone abrasive slurries and using this hybrid slurry in a similar manner to straight stone only slurries.

At this point I have both a paper and Balsa slurry ‘library’ that I’ve collected over the years.

One interesting ‘trick’ in using these slurries is that, in addition to usually getting a finer finish than the original stone, by applying paper under various supporting structures from glass to neoprene, you can control the ‘hardness’ of the stone. So for instance, you could take the swarf from a 30K Shapton and put it, dried on paper, over a piece of neoprene / mouse pad and make a ‘soft’ 30k Shapton surface for a convex edge. Or take a soft natural stone like a Hakka Tomae or Monzen Aoto and, using this technique, put the dried mud on paper over glass to produce a hard Hakka stone effect, making the surface suitable for a straight razor which usually prefers a harder stone. You could also take a natural stone like a Shinden suita, which has pores or ‘su’ that clog and use the swarf rather than the stone directly, eliminating the clogging issue entirely. And so on.

Collecting these various swarfs on balsa for the WEPS would be a fun sub-hobby in itself 🙂

—
Ken

[Ken Schwartz]

“It is confusing, because a lot of people say they work with “green paste” or “red paste”. Green paste often contains chromium oxide with a grit size of 0.5 micron (although I also encountered chromium oxide with a grit size of 3 microns ) ”

Chromium oxide (CRO) is not as precisely specified as good diamond and CBN products. It is a dual use product and is often used as a pigment in paints where precise grit specification is not at all critical. Sometimes this same stuff is used for honing (sharpening/ stropping). Because it is so much cheaper than diamond and CBN, it like aluminum oxide is a commodity product usually purchased in coarser amounts than individual carat weight (grams to tons)

I have tested various CRO products specified as being as fine as 60 nanometer (0.060 microns) particles and 0.3 microns (300 nanometers) and found horrific discrepancies from their advertised sizes, some having mean particle sizes well in excess of several microns and with very broad variances and various contaminants. If you wish to use CRO, I would strongly recommend you not using the powdered form, but rather get it already formulated in a paste or slurry formulation from a reputable vendor. The powder is a serious irritant to eyes and respiratory system (lungs, etc) and I wouldn’t work with it without a hood and a respirator for fine particulates.

I’m not a big fan of green sticks which usually contain low grade CRO that are loosely specified grit sizes, plus other abrasives (contaminants).

—
Ken

[Author]

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