Question about Bark River stropping compounds

D

Dr. Grits

Joined
May 14, 2010
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3
About a year ago, after reading several recommendations on this and other forums (or is it fora?), I purchased the combo pack of Bark River green & black stropping compounds. I have been using them continually since with great results. A couple months ago I began considering adding a strop with the white compound, thinking it would be courser than the black and add a little more aggression for touching up slightly dulled blades. I found a site that sells these compounds seperately, but now I'm confused. This vendor indicates that the white compound is actually finer than the green (I had thought it was courser than the black). But what confused me even further was that the vendor's description stated that the white compound's grit was equivilent to 12,000 (the green 6,000 and the black 3,000). They did not mention micron size. I know that the green chromiun oxide is tipically .5 micron, and have assumed the black to be about 1 micron. I know that there are several grit size rating systems, so I am more concerned about micron size at this level of fineness. Can anyone help remove this cloud of confusion and enlighten me as to the micron sizes of these excellent Bark River compounds?
 
Somebody pointed out, in another thread recently, that some of the 'green' bar compounds are a mix of chromium oxide (very small) and much coarser particles of aluminum oxide. Point being, a few of us had noticed some fairly noticeable hazing/scratching left, after using the green bar-type compounds. I dislike vendors' use of the 'grit' term only, for the same reason as you. It's ambiguous at the least, and maybe deceptive at the worst. If it were me, I'd call Bark River and ask them what the actual particle size is, in their compounds (and what abrasive mix, if any). They might not be able or willing to tell, in which case I might consider using something different. I've heard, for the most part, people seem to be happy with Bark River's compounds, in terms of sharpening performance. I'm not bashing them, but it does bug me if a vendor doesn't know (or won't specify) what the actual abrasive type/mix is, and what the real particle size is. Makes it tougher to predict the results, if a particular edge finish is the goal.
 
yes but even when they state a micron size it's an average rating, for exemple typical 1 micron compound is 1 micron average, meaning that the particles are ranging from 0 to maybe 2 microns (typicaly 0,5 to 2) but the range can be smaller or larger depending on the manufacturer. and that for the same advertised avg size.
 
I think you are confused the white compound is more fine than the green compound. Not more coarse.
 
White (aluminum oxide) can be fine, medium or coarse. In most compounds, it can range anywhere from ~1 to 10 microns or more. The green (chromium oxide) is typically smaller finer than most white compounds, at an 'average' particle size around 0.5 micron, from most makers. This is another reason why a description by color or 'grit' only, is often vague and confusing.

As I stated earlier, some makers apparently mix abrasives in so-called 'green' compound. If it's described by a particualar maker as more coarse than the white, I'm inclined to believe it's a mixed variety. The 'pure' chromium oxide (which is green in it's natural state, and gives 'green' compound it's color), will almost always be finer.
 
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neeman said:
From dlttrading
http://www.dlttrading.com/bark-river-sharpening-accessories.html


Black approximately 3,000 grit
Green approximately 6,000 grit
White approximately 12,000 grit

How to transalate grti to microns?
Who knows?
Click to expand...

As mentioned earlier, that's the big question. Best thing is to ask them (and if they can't or won't specify, BEWARE). Unless the manufacturer references a specific grit standard (ANSI, JIS, etc.), there's no sure way to tell. Anybody's guess.
 
ECONabrasives has no idea what the grit or micron level of their china made compounds that they sell.
 
Why not buy a bar of white compound and find out what it's like? I've been using white in favour of the green for a few months now and I think I prefer the results of the white.
 
Very old thread but didnt wanna create a new one

So can anyone plz confirm. Im making my own strop and need to buy a compound but emulsion or paste would consider as well. Just need some expert opinion plz.
 
I am not an expert by any means but I have a couple of paddles from Flexx Strops which are supposedly loaded with BRKT compounds. I have black, green and then white and they range from coarse to fine in that order. The confusion is there because some other makers do indeed use white as a coarser substance with black as the finer substance but this is not BRKT's grit scale related to those colors as it is the reverse of that! My own personal conclusion about the whole set up of the strop paddles and the sparsely applied compound is Mehhh!
 
Use CBN or diamond paste or spray.. It's sold by micron size, ranging from 80 micron to .025 micron.
 
pwet said:
yes but even when they state a micron size it's an average rating, for exemple typical 1 micron compound is 1 micron average, meaning that the particles are ranging from 0 to maybe 2 microns (typicaly 0,5 to 2) but the range can be smaller or larger depending on the manufacturer. and that for the same advertised avg size.
Click to expand...

I tend to agree with "pwet" because I've found that there really isn't a uniform rating system for many of the stropping or polishing compounds. Because it's been my results that each vendor or manufacturer kind of has their own protocol on what they deem as coarse, fine, ultra-fine ect. It's a whole lot easier to determine what grits are for benchstones and various ceramic files but there are so many lapping compounds, stropping compounds, polishing media. And the type of abrasive really plays a huge part in your results.

I've even looked at some of the compounds that the rock hounds use to polish their fancy rocks in a rock tumbler. And I've had some interesting results using some of them on a strop. There just isn't a reliable, dependable rating system for these types of compounds. You just have to actually use it sometimes to see what the desired results will be for what you are working on. I kind of just look for high quality compounds and abrasive products and try to stay with reputable vendors. I've had good luck with Vendors like JapanWoodWorker, Garrett Wade and 3M abrasives to name a few I've had decent results with. I also try to stay with USA, German, Japanese and Canadian made products for the most part.
 
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Aerosmith101 said:
Just Google grit to micron I know that 12000 is typically about 1 micron
Click to expand...

I just realized that the bark river compound is on the grand unified grit chart And according to it the black is 20 microns and the green is 0.92 it doesn't have the white compound though
 
Bark River does have a 12,000 Grit White Compound, i am in the process of charging my strops with it, will let you know the results later on.
 
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