Making stropping compound

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Øystein Lytskjold

Joined
May 8, 2011
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18
Hello

I have recently acquired some silicium carbide from SiC processing (my father works with them). This is extremely fine dust, made for cutting silicon wafers for solar panels.
I was thinking that this stuff may be good to make my own stropping compound from, and was as such wondering what i should use for the "sticky stuff".

I am thinking wax is too hard, so would molten wax mixed with vaseline make it softer when it cools down?
 
I am no expert for sure but it seems like you could mix the powder with some light oil of some kind and then rub it into your stop. Someone will tell you the best way. Do you know the size of the particles?
 
Some carrier agents;
Mineral oil
Vaseline
water
pure bee's wax
dish washing soap
white glue
rubber cement

Vary the carrying agent to match your substrate


Stitchawl
 
or nothing. just rub some grit on your strop. if it's fine enough it will embed itself in the leather.
 
I currently use SiC dust for just about all of my stropping needs. Mixed with dish soap it works great, it would be nice to know what the rating is for your dust. There's very little visual or tactile difference between 600 and 1200 grit lapidary powders, but there's quite a bit of difference when you put a knife to them. All depends on what your goals are.

HH
 
It hadn't occurred to me that people are still interested in working with dry SiC and other compounds - I have quite a bit in old stock.

Maybe I should bring it back - no?

Keith
 
handamerican said:
It hadn't occurred to me that people are still interested in working with dry SiC and other compounds - I have quite a bit in old stock.

Maybe I should bring it back - no?

Keith
Click to expand...

What is the finest grade you have on hand? 1200 is the highest grit count I can find currently.

HH
 
Off the top of my head on super fine I have 2 & 6 micron SiC green which is a variation of the compound that's rated 9.5 on the Mohs scale.

I'll have that and others available in a week or so - thanks for asking,
Keith
 
I just asked my father how fine the stuff they produce is but he couldnt remember the exact numbers. Im guessing its extremely fine though since its used to cut insanely thin wafers of silicon.
 
Did some looking into it and it sounds like that powder could be anything from the two hundreds through FFF. I can't find a girt rating for F,FF, or FFF but they're all higher than 1200 which does a real nice job for a fine polish - only .5 CrO is finer IME. Anything much higher and you've potentially got some nice compound. It would be very helpful to know what it is - they'll all work well, but hard to say what its best for without a lot of trial and error. Another consideration is that these industrial powders also sport specific crystalline structures, could make for some fun testing.

HH
 
Just heard back from dad, the dust is 8 microns, so not really the finest. Im thinking it will do a nice job of it though.
He has been keeping a box of it in his garage where he is building an old AC Cobra, trying to figure out how he can use it for polish on some visible aluminium parts.
Now that I have picked up an interest in this as well we have planned to do some heavy testing (not very scientifically though) in a couple of weeks.
I'll post the result here if we find anything useful.

By the way. I have some stropping compound i bought from Knifecenter a year and a half ago. I cant really identify the maker of the stuff, but its a couple of small square "sticks" of brownish red compound and some sticks of black. They seem to work ok on most of my knives, but doesnt seem to have any noticeable effect on my Fallkniven S1. Could it be that the steel is too hard for the abrasive in the compound?
I't doesnt seem like Knifecenter sells the compound any more, so i cant find any specifics.
 
8 micron is about 700 grit. You'd be surprised how nice a job that might do. Most of my EDU knives are sharpened at 400 grit wet/dry sandpaper and stropped with 600 grit SiC. Done well this will shave the stubble off my face and easily shave arm hair etc. A very nice edge for general use IMO.
HH
 
Really? Not finer than 700 grit? And thats the same grit "scale" as used on for example M3 wet/dry? Because i normally go 600, 800, 1200 or 2000 depending on what i feel the edge needs, and then last to my strop with brownish red compound. So if the 8 micron SiC will leave deeper scratches in the blade than what the 800 grit wet/dry paper its not really very good for polishing?
 
Hard to say, there's a big difference between a bonded abrasive and one that can move around on a strop. My best estimation is that the loose grit on a strop is going to produce scratch pattens closer to 1/2 what they're rated for. 700 grit loose compound will be close to the scratch pattern from a 1400 grit paper. Even then it doesn't tell the whole story as it won't be creating a burr and it isn't really grinding anymore even if it does remove some metal. All I can say for sure is that my black emery compound is rated about 600 grit and my 600 grit SiC does a much better job. Whip up a cheap homemade strop and try it out. It probably won't work well for the 2000 grit wet/dry, but it should do a good job at 1200 and certainly at 800. There's also the shape of the abrasive to consider. I enjoy tinkering, there's no way I wouldn't try it out.

HH
 
Well, since i love tinkering as well, im not giving up just yet :P
I think it should work fairly well, as my dad reports that all metal railings at the factory has gotten a mirror finish.
 
HeavyHanded said:
Hard to say, there's a big difference between a bonded abrasive and one that can move around on a strop. My best estimation is that the loose grit on a strop is going to produce scratch pattens closer to 1/2 what they're rated for. 700 grit loose compound will be close to the scratch pattern from a 1400 grit paper. Even then it doesn't tell the whole story as it won't be creating a burr and it isn't really grinding anymore even if it does remove some metal. All I can say for sure is that my black emery compound is rated about 600 grit and my 600 grit SiC does a much better job. Whip up a cheap homemade strop and try it out. It probably won't work well for the 2000 grit wet/dry, but it should do a good job at 1200 and certainly at 800. There's also the shape of the abrasive to consider. I enjoy tinkering, there's no way I wouldn't try it out.

HH
Click to expand...

Øystein Lytskjold;9633614 said:
Well, since i love tinkering as well, im not giving up just yet :P
I think it should work fairly well, as my dad reports that all metal railings at the factory has gotten a mirror finish.
Click to expand...

Ask your dad what they use for the backing material for the SiC dust, when polishing those silicon wafers (and the metal railings at the factory). As HH points out, the relative hardness/softness of the backing makes a big difference in the effective grit. A larger particle on a soft backing won't 'dig' as deep into the steel, resulting in a finer scratch pattern and better polish (within reason, of course).

I've been playing around with different backing materials for Simichrome polish. I've noticed a big difference in results, comparing a balsa backing to leather. The great thing is, using the balsa results in more efficient (aggressive) removal of metal, which takes the edge up another notch in sharpness. Then, using the same compound on leather will polish it up even more, but less aggressively.

If I'm not mistaken, SiC is also known for 'fracturing' into smaller, but still very sharp, crystals, with use. Many here are familiar with how wet/dry sandpaper (SiC) will effectively get 'finer' with use. So, even though the particles might start out at 8 micron, I'm betting it'll get smaller with some use. I've noticed, with the finer grits of wet/dry sandpaper, they'll start to produce a higher polish as the paper gets 'older'. My 1000/2000 grit strips I've been using, have started to look pretty worn out, but I've been reluctant to toss 'em out for this reason.
 
Last edited:
Obsessed with Edges said:
Ask your dad what they use for the backing material for the SiC dust, when polishing those silicon wafers (and the metal railings at the factory). As HH points out, the relative hardness/softness of the backing makes a big difference in the effective grit. A larger particle on a soft backing won't 'dig' as deep into the steel, resulting in a finer scratch pattern and better polish (within reason, of course).
Click to expand...

I should let OL respond, but I saw this question and thought I'd add what I discovered about it last night. Apparently the normal use as a slurry that sits around a wire saw (composition and gauge ?). The wire pulls the grit into the cut and effectively saws materials that would otherwise be too tough, and does so with a high degree of accuracy. Full details were not easily available, but I would like to know more. They come in a wide variety of grit sizes and crystalline structure depending on application.

HH
 
HeavyHanded said:
I should let OL respond, but I saw this question and thought I'd add what I discovered about it last night. Apparently the normal use as a slurry that sits around a wire saw (composition and gauge ?). The wire pulls the grit into the cut and effectively saws materials that would otherwise be too tough, and does so with a high degree of accuracy. Full details were not easily available, but I would like to know more. They come in a wide variety of grit sizes and crystalline structure depending on application.

HH
Click to expand...

That's an application I hadn't even conceived of. I suppose the high accuracy (depth of cut, I assume) comes from those 8 micron 'teeth' on the saw? Does sound interesting. I too, would like to hear more about this.
 
The stuff comes in grit ranges all the way down to FFF - whatever that is. 1200 is mighty fine stuff and then it goes F, FF, and FFF. Other uses include cutting granite. I did receive a response from a company "Washington Mills" that make the stuff. I have no idea what questions to ask, but she did say samples were available....!

HH
 
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