Stropping Compound

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FlyingMuskrat

Joined
Jan 9, 2006
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I am thinking about ordering a strop from Hand American but need some help deciding about stropping compound. I think that Chromium Oxide would suit my needs, but should I get the dry or the paste? Would I just mix the dry with a little bit of water or some kind of oil and rub it into the strop? Thanks in advance
 
I would get the paste, easier. But yes you can mix the powder with some mineral oil or some petroleum jelly melt some parafin wax and mix it with that. Don't use water, makes the leather stiff over time.
 
Lee Valley Tools sells a Chromium Oxide stick that works great -- just rub it on like a big green crayon.
 
Boron carbide is just slightly less hard than a diamond. It is a great stropping compound.
 
I am fortunate enough to have one of those TORMEK wet grinder, sharpening systems ( www.sharptoolsusa.com) . The TORMEK brand aluminum oxide paste I get from them is really great stuff. I have used it on razor strops and it works great.

But I would also bet that anything you would get from Handamerican or Japan Woodworker would also be high quality.
 
I like the gel. And if you want to make some more aggressive strops just mix the diamond paste/powder with the gel. I bought $25 worth of leather there and have enough to last forever. Even so next order I'm going to get some of the thinner leather.
 
FlyingMuskrat said:
Are there any steels/hardnesses that Chromium Oxide won't work on, where the Boron carbide would?
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Only trial and error will answer that question. The boron carbide seems to be a bit faster cutting but it is also coarser than the 0.5 micron chrome oxide. The real question to be answered is just how fine of an edge are you trying for and will that edge hold up to the intended use?
 
FlyingMuskrat said:
Are there any steels/hardnesses that Chromium Oxide won't work on, where the Boron carbide would?
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From my experience, no, but technically, some of the carbides are about as hard as CrO. I haven't played with diamond and BC powder enough to really say, but on steels with large carbide volumes, there might be an advantage. By now diamond powder in all kinds of grid sizes are available and resonably affordable so it is fairly easy to find a diamond replacement for 0.5 micron CrO or to go finer or coarser. Boron Carbide seems to me a bit of a gimmick. It is actually substantially softer than diamond (about a factor of 2), but since it is still twice as hard as the hardes carbides found in steel, that hardly makes a difference. It doesn't seem to be really all that much cheaper than diamond at the moment though and there seems to be a lower availablility of different grid sizes....so why (don't get me wrong, I don't see a problem with it, but I don't see much of an advantage over diamond powder, but may be BC has gotten drastically cheaper since I last checked)? Supposedly, diamond desolves in the steel during grinding, but I doubt that that will be much of an issue when stropping manually.
 
When going really high pressure/high speed, diamond can melt into steel, but that's only a concern if bearing down hard with a grinding wheel or a buffing wheel.

Boron carbide powder can be had in 0.7 micron size from ESK/Ceradyne. By the pound, it's only $6.25 per ounce shipped from Germany to the USA. One pound of boron carbide powder will make several pounds of compound when mixed mineral oil, glycerine, or any other goo-making substance.

Diamond and cubic boron nitride can be had pre-mixed (or unmixed) and had in even smaller sizes (0.1 microns for diamond and 0.25 microns for both) if needed.
 
Just corrected that. That was the per ounce price. It's $100USD shipped, or was when some of us went in on a group buy. :o
 
Of the commonly used stropping compounds, are any non-toxic? Since I am working primarily with kitchen knives, I'd like to find something non-toxic, even if it isn't as effective.
 
After reading a few MSDSes for chrome oxide compound, it doesn't look like the health hazard of ingesting small amounts of the stuff is very bad. If the knife is thoroughly cleaned and dried after stropping, I don't foresee it being a major issue. Then again, I'm no doctor and won't be held responsible for anyone ingesting anything. I have used stropped knives for all my cooking over the last several months with no ill effects noticed.

I'd wager the least toxic or irritating abrasive you'll find is jeweler's rouge. It's essentially rust suspended in paraffin.
 
I bought a stick of CrO from Lee Valley. Soon thereafter, I was in the local Sears hardware store, and noticed they had what looked like the same thing only much cheaper (as in about $3 per bar). Plus, they had bars of white, black and red compounds.
 
DainBramage said:
Of the commonly used stropping compounds, are any non-toxic? Since I am working primarily with kitchen knives, I'd like to find something non-toxic, even if it isn't as effective.
Click to expand...

Most are non-toxic but they are sharp, little bits of rock that are harder than steel and probably no treat in the tummy or windpipe. With compounds, the tummy is the most likely entry point. To reduce that risk, you can wash your knives in gelled rubbing alcohol after stropping to remove the compounds, abrasive, and residual steel dust.

The alternative I usually use is to strop on polishing paper or lapping film with a flat piece of glass as a backing (I use the Hand American Flatbed Hone and their optional glass plate, but any hard, flat surface will work). With polishing paper and lapping film, most of the time, the abrasive stays right on the paper or film (less likely with the coarse grit stuff, but we're talking about stropping) and sharpened off bits of steel usually stick there too (as a dark gray streak or smear). 3M brand is the easiest to find these days, but they do have competitors (google "lapping film" or "polishing paper" for some sites or go straight to www.leevalley.com www.toolsforworkingwood.com www.psidragon.com http://rshughes.com www.ottofrei.com and search around).
 
KeithAM said:
I bought a stick of CrO from Lee Valley. Soon thereafter, I was in the local Sears hardware store, and noticed they had what looked like the same thing only much cheaper (as in about $3 per bar). Plus, they had bars of white, black and red compounds.
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That is the stuff I use. The white and red from Sears for less than $3.00 per stick. At the rate it gets used on stick will last me a long time.
 
thombrogan said:
Most are non-toxic but they are sharp, little bits of rock that are harder than steel and probably no treat in the tummy or windpipe. With compounds, the tummy is the most likely entry point. To reduce that risk, you can wash your knives in gelled rubbing alcohol after stropping to remove the compounds, abrasive, and residual steel dust.
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May I ask if anyone also uses it? This sounds great to me also as an occasional antimicrobial cleaning for the knives.
Perhaps use an alcohol spray? If so should one rinse it afterwards or let it dry out? (i.e. does alcohol have an increased effect on rusting like water?)
 
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idanp said:
May I ask if anyone also uses it? This sounds great to me also as an occasional antimicrobial cleaning for the knives.
Perhaps use an alcohol spray? If so should one rinse it afterwards or let it dry out? (i.e. does alcohol have an increased effect on rusting like water?)
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(This is a 12-year-old thread, but...)

Most any liquid cleaner can be used to remove residue of stropping compounds. Dish soap & water, isopropyl alcohol, Windex (what I use, most of the time), etc. Really doesn't take much to remove it, if the cleaning medium used is wet and/or soapy. 'Stropping' the blade on a microfiber towel moistened with Windex has worked well for me, for example. Alcohol-based gel hand sanitizer could work, I'm sure. But it has no particular cleaning advantage over the other options mentioned. Clean your knives more or less like you'd clean kitchen cutlery (avoid the dishwasher, maybe), and you'll be fine.

Alcohol, by the way, won't create any direct risk of rusting by itself, save for it's tendency to dissolve and wash away any oil that might otherwise protect a non-stainless blade (oil them again after using it). In fact, isopropyl alcohol will bond with water molecules; as the alcohol evaporates, it'll carry moisture (water molecules) away with it. It's an effective way to remove all residual water from knives after washing them, by flushing them out with IPA afterwards.

Ingestion of very minute amounts of stropping compound won't likely hurt you anyway. The real health hazard with these is through respiration, i.e., inhaling the dust of unbound dry compounds. Once that's in your lungs, it'll never come out. This ordinarily wouldn't be much of a hazard with waxy-bound compounds which are clumpy and don't get airborne easily, or liquid-based compounds. But dry, powdered, unmixed compound gets airborne very easily, and you have to be careful with it, to avoid inhaling the dust.
 
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Obsessed with Edges said:
(This is a 12-year-old thread, but...)
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I didn't want to start a new thread since this one was already there (and relevant :)).

Obsessed with Edges said:
Most any liquid cleaner can be used to remove residue of stropping compounds. Dish soap & water, isopropyl alcohol, Windex (what I use, most of the time), etc. Really doesn't take much to remove it, if the cleaning medium used is wet and/or soapy. 'Stropping' the blade on a microfiber towel moistened with Windex has worked well for me, for example. Alcohol-based gel hand sanitizer could work, I'm sure. But it has no particular cleaning advantage over the other options mentioned. Clean your knives more or less like you'd clean kitchen cutlery (avoid the dishwasher, maybe), and you'll be fine.

Alcohol, by the way, won't create any direct risk of rusting by itself, save for it's tendency to dissolve and wash away any oil that might otherwise protect a non-stainless blade (oil them again after using it). In fact, isopropyl alcohol will bond with water molecules; as the alcohol evaporates, it'll carry moisture (water molecules) away with it. It's an effective way to remove all residual water from knives after washing them, by flushing them out with IPA afterwards.
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Thanks for all the info :). I assume you don't use Windex on your kitchen knives unless you thoroughly rinse it afterwards or something since I read it isn't food safe.
I read a lot of things about oiling and have avoided it until now since I dry my knives quickly after use. I think I will try some rubbing alcohol gel (wonder if there are any relatively pure ones without any perfumes and other added chemicals).

Obsessed with Edges said:
Ingestion of very minute amounts of stropping compound won't likely hurt you anyway. The real health hazard with these is through respiration, i.e., inhaling the dust of unbound dry compounds. Once that's in your lungs, it'll never come out. This ordinarily wouldn't be much of a hazard with waxy-bound compounds which are clumpy and don't get airborne easily, or liquid-based compounds. But dry, powdered, unmixed compound gets airborne very easily, and you have to be careful with it, to avoid inhaling the dust.
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May I ask how can one avoid getting it airborne? I assume every time you rub it (the solid form) on your stropping surface and while you strop some of it will be released into the air.
 
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