fast/slow/polisher

I now have 3 coticules one select , one kosher grade, and my newist vintage. i did 50 laps on each with slurry select and kosher seemed to cut the same only slightly turned creamy slurry a tiny bit grey whilst to my surprise mant the vintage which seemed the hardest turned slurry almost purple/dark grey cuts fairly quik. so now i no they do vary some are the same as each other but how do i tell which one polishes the best. I also noticed the tiny vintage when honing on water only down the edge of hone mainly in corners i had to wipe as a dirty substace very light was apearing which made me think this is actual removing visable metal with only plain water not a lot but i noticed it straight away, even though the surfice feel like glass its so smooth. never noticed this on my other yellows.

I sometimes check out the existing scratch pattern on an edge and then do some laps and check it again and see if it is smoothing out. If you really want to assess the cutting power of each coticule do that with each of them with the same amount of laps and razors with close to the same scratch pattern.

The softer coticules will raise a slurry just with honing. For initial honing work, this is a great thing, but for polishing it is not because the hone is constantly releasing more cutting material and effectively acting like a lower grit, non-polishing, hone. It sounds like your vintage hone is in this softer category and is therefore not likely to be a good polisher. A good polisher is harder and is not prone to release slurry when honing with water.

i supose i could just hone my razor on the 4k and try each coticule chek scratches and see what happens then go 4k again and try next coti and see which one reduces scrathpattern the best. Other than that i have polished with each one and never noticed any thing bad so they must be ok. after slurry honing and then i finished on water i have to say depite people saying slurry can dull the razor shaved well maybe not ultra sharp but i have to say first time i have honed on yellow slurry then water i usauly use bbw slurry then yellow water the shave was very smooth i think for defanat the yellow with slurry then water gives a very smooth comfortable shave.

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Originally Posted by Utopian

The softer coticules will raise a slurry just with honing. For initial honing work, this is a great thing, but for polishing it is not because the hone is constantly releasing more cutting material and effectively acting like a lower grit, non-polishing, hone. It sounds like your vintage hone is in this softer category and is therefore not likely to be a good polisher. A good polisher is harder and is not prone to release slurry when honing with water.

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thats what i have read softer coticules are not good polishers but that is the thing my vintage i have to realy rub it to get a slurry i did 100 passes on it with a customers razor and it did not produce a slurry at all naked to my eye the water just stayed water and it feels very glassy it actualy as a marble looking finish yet it a mazed me when it turned the slurry dark grey purplish i have repeated again it defanatley cuts quiker than my other two.

there is apicture of it on honing section under vintage coticule it is a combo

If I use a slurry on mine, especially a lot of thick slurry, the slurry will turn from a creamy white color into a dark gray color after it gets enough metal in the slurry. If I use it with just water, light gray lines will appear on the surface of the hone, but they wipe off easily. The lines let me know that I am keeping my stroke fairly consistent and that some kind of progress is being made. I'm not sure what that says about the hardness of it, but what you say about yours seems to be what happens with mine sometimes.

well i made slurry on all 3 the same, and my vintage cut quikest and slurry turned dar grey my other two no where near the slurry had a tint of grey thats all and no lines of swarf at all but what you describe as wipes of easy same thing on my hone and it wiped of with my fingers which makes believe its my fastest cutter and also coticules do vary yet my other two are moraless the identical in the way they hone. having said that the vintage worked great on my bismark with slurry and with out

I wonder if the rate of color change in the slurry is an indication of anything. Would the slurry end up darker on a stone that does not create slurry quickly as new slurry is not being added to the mix? Or would the addition of more slurry created when just honing add more cutting particles and therefore cut more metal?

Sometimes, to increase the cutting ability of a coticule, I'll use a bbw slurry and make a "purple slurry" on a yellow coticule. The possibilities are numerous. Since Coticules are a natural stone, Most behave differently than others. IMHO, A coticule mined 100 years ago, or 1 year ago hold no great differences in that respect. Many folks believe the ones mined 100 years ago are somehow better. This is a complete falsehood. Some believe the garnet content is higher. There's absolutey no hard evidence of this. You can get one mined yesterday that performs as well if not better. It really depends on the stone itself. Both stones are 500 million years old give or take 100 years. Kosher, simply means no flaws throughout the stone, Select grade has no visable flaws, Standard grade has visable flaws. You can use your fingernail and do a scratch test to tell if a coticule is Hard, Soft, Medium, Whatever. I have many, each are different. Normally, I won't mix slurries, but on Coticules and BBW's it's fun, and you get some good results. Don't be afraid to experiment. Slurries will darken as metal accumulates in the slurry, it'll turn grayish.....Gary, I think your Vintage is just a better coticule, faster cutter, not because it's vintage.
Where did you get the others? Also, I'd like to get some feedback from Coticule users. I read where guys are doing 50, 100, 200 strokes. This seems excessive to me, but maybe it's just me.

Does making the purple slurry on the yellow allow you to get the razor sharp? Or sharper than just the yellow with yellow slurry? Does it cut at a different rate?

At the moment I really have no reason to use a slurry other than I just want to learn what I can do with the stone I have. I have reset a few bevels with it, but I do not remember the number of strokes. It had to be more than 50, though, and I was aiming for a little bit of overkill. I couldn't tell you what the minimum would be to reset a bevel. I have been pretty much erasing any trace of the coticle with slurry with a shapton 12k pro, which cuts pretty fast, and then finishing on the coticle with water, so I can't say how it effects the final edge. I will say that it does a pretty good job of getting an edge in the ballpark for finishing. I have yet to really do much with the blue.

As far as finishing with the yellow coticle with water, 30 laps after the 12k does a good job for me. Then onto at least a hundred laps on leather. I will say that more laps on the leather does make a difference. I found today, which was the second shave off of the same carbon steel dovo razor finished as described above, that the shave was a little bit better than the first (seemed a little bit smoother and cut just a little bit better). I attribute that to the added laps on the strop before shaving, which was about a hundred. So, 200 laps on leather makes for a decent shave. The amount of laps on leather is making me consider getting a canvas strop as well.

I have done the scratch test on my coticules they do not mark there defanatley not soft i'd say medium to hard my other two one from rob and one from invisable edge and i have combo 6x3 on its way from howard. The bbw all seem the same why they say use bbw first then yellow i don't no some say the blue does the cut and yellow polihing. With my experimenting i would say yellow makes a smoother edge i have shaved straight of blue slurry and no probs i have shave of yellow light slurry and shaved but felt likevelvet not sharper.As for how many laps it does'nt matter they both it a peak and level of i have never over honed you carn't. I had a razor that was sharp but felt real harsh i reckon it was over done on my norton , i did 100 sl/yellow bbw/50 /yellow water and it was smooth it took care of the over honed edge. You could do less laps and just repeat untill your happy. invisable edge explained to me blu and yellow are both the same stones yellow is faster cutter blue is slower he prefers to finish on his blue in most cases he hones many razors and he says slurry has to be used he does. I 'd say he is probably right . they both cut and polish so slurry just speeds it up. I have had one experiance when i used thick slurry it did dull my edge but 100 laps on water brought it back. that is why i always like to finish on water.When i shave tomorrow straight of yellow slurry i will see let you guys no.