Crayons as stropping compound?

Obsessed with Edges said:
I've been looking up some info on the web, and with regard to the 'crayon-like pastel artist thing', I've found some info regarding so-called 'artists soft pastels'. Many of these use either iron oxide or chromium oxide (and other oxides) in their pigment, depending on the color. As an example, here's a link to one maker's products, regarding the composition of their soft pastels:

http://www.winsornewton.com/main.aspx?PageID=311

I could see why Crayola (the brand) wouldn't want to use anything toxic in products marketed for use by children, but other makers of 'art supplies' evidently aren't as concerned about it.
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yup, thats it. Soft pastels is what i have. Haha guess it could work.
 
Obsessed with Edges said:
I've been looking up some info on the web, and with regard to the 'crayon-like pastel artist thing', I've found some info regarding so-called 'artists soft pastels'. Many of these use either iron oxide or chromium oxide (and other oxides) in their pigment, depending on the color. As an example, here's a link to one maker's products, regarding the composition of their soft pastels:

http://www.winsornewton.com/main.aspx?PageID=311

I could see why Crayola (the brand) wouldn't want to use anything toxic in products marketed for use by children, but other makers of 'art supplies' evidently aren't as concerned about it.
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They are probably mostly Iron oxide, as it's cheaper than Chromium.
Iron oxide CAN be used as stropping compound, but it's literally softer than the steel causing EXTREMELY slow cutting. Even a little amount of Cr2O3 (I think :P don't want to type CrO since that's wrong) will greatly speed up the cutting action of Iron oxide
 
chococrazy said:
They are probably mostly Iron oxide, as it's cheaper than Chromium.
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That would work for red crayons. Green ones would need the CrO to make them green (if using this sort of pigment and not using dyes.)

Even a little amount of Cr2O3 (I think :P don't want to type CrO since that's wrong) will greatly speed up the cutting action of Iron oxide
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CrO3 would be chromium trioxide! Actually, I've found sites that call Chromium Oxide CrO, CrO2, Cr2O2, and CrO3 so I guess even the chemists don't know what it should be! How the heck should we?!@! :eek:

Stitchawl
 
What with all the discussion as to which is which, my curiosity led me to this info on Wiki:

CrO = Chromium(II) Oxide = BLACK powder in it's natural state
Cr2O3 = Chromium(III) Oxide = GREEN; used as pigment and as abrasive
CrO2 = Chromium(IV) Oxide = Chromium Dioxide; synthetically produced magnetic substance
CrO3 = Chromium(VI) Oxide = Chromium Trioxide = dark red/orange brown solid; used mainly for electroplating

So, I'd assume Cr2O3 is the one...
 
KarlMaldensNose said:
If I had to really stretch on this one and come up with a answer, I'd say the colour pigment might be an abrasive. But the only reason I offer that is b/c chromium oxide is used as colour pigment.

I think he's pulling our legs. He's gotta be... right?
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Obsessed with Edges said:
What with all the discussion as to which is which, my curiosity led me to this info on Wiki:

CrO = Chromium(II) Oxide = BLACK powder in it's natural state
Cr2O3 = Chromium(III) Oxide = GREEN; used as pigment and as abrasive
CrO2 = Chromium(IV) Oxide = Chromium Dioxide; synthetically produced magnetic substance
CrO3 = Chromium(VI) Oxide = Chromium Trioxide = dark red/orange brown solid; used mainly for electroplating

So, I'd assume Cr2O3 is the one...
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It better frickin' not be. Chrome oxide colorants are no longer used in the United States as a colorant. Especially not in crayons. They have significant toxicity issues. We pulled the chrome colorants out of coatings formulations in the 80's.
 
Though the crayon used is in question Crayola uses wax and dye, I looked through all the MSDS I could find and found no abrasives.
 
I was really tempted to tell you guys that I rubbed cat poop on a leather strop, and I got a stinking sharp edge! ;)
 
knarfeng said:
It better frickin' not be. Chrome oxide colorants are no longer used in the United States as a colorant. Especially not in crayons. They have significant toxicity issues. We pulled the chrome colorants out of coatings formulations in the 80's.
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Do a Google search for 'chromium oxide green' or 'chromium oxide pigment', and see how many hits you get related to art supplies. Evidently, it is sold (widely, from what I can see) as a colorant in the U.S., by U.S. based companies.

I do see that one form of chromium oxide, known as hexavalent Chromium or Chromium(VI), used in electroplating and some treated lumber, does have documented toxicity issues. Chromium(III) based compounds, like Cr2O3, are the ones that I'm seeing widely in art supplies (oil paints & pastels).

Take a look at FDA's web site, and search for chromium there. You'll even find that it's allowed for use as a pigment in cosmetics in the Chromium(III) form.

Chromium is even documented as a dietary supplement in relatively low doses.

Not trying to pretend to be a chemist or any other kind of expert on the subject, just passing along what I'm finding on the web so far in my search to learn a bit more...
 
Of course I have a sense of humor!
You just don't know how many of these posts I laugh at!
 
Obsessed with Edges said:
Do a Google search for 'chromium oxide green' or 'chromium oxide pigment', and see how many hits you get related to art supplies. Evidently, it is sold (widely, from what I can see) as a colorant in the U.S., by U.S. based companies.

I do see that one form of chromium oxide, known as hexavalent Chromium or Chromium(VI), used in electroplating and some treated lumber, does have documented toxicity issues. Chromium(III) based compounds, like Cr2O3, are the ones that I'm seeing widely in art supplies (oil paints & pastels).

Take a look at FDA's web site, and search for chromium there. You'll even find that it's allowed for use as a pigment in cosmetics in the Chromium(III) form.

Chromium is even documented as a dietary supplement in relatively low doses.

Not trying to pretend to be a chemist or any other kind of expert on the subject, just passing along what I'm finding on the web so far in my search to learn a bit more...
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But they are not used in crayons.
Like I said, we removed Chrome based pigments from common house paint several decades ago. There are still some used in industrial coatings. Chrome based pigments are still used in some art supplies, but not the ones designed for children.

If you find a child's crayon containing chrome pigment then the crayon was made in China and is not made to US standards.
 
stitchawl said:
I wonder if there is some way to learn the size of the Cr2O3 particles used by various companies for their pigments?

Stitchawl
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Can't speak for artists paints. Inorganic industrial paint pigments run ~ 0.1 micron to 1 micron depending on which pigment it is, the company making it, and the type of coating for which it is designed.
 
knarfeng said:
Can't speak for artists paints. Inorganic industrial paint pigments run ~ 0.1 micron to 1 micron depending on which pigment it is, the company making it, and the type of coating for which it is designed.
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And off-hand idea who makes paint with the smallest Cr2O3?

Oh, BTW, you can find your vorpal blade tracking it by sound. It goes 'snicker-snack.' Hope that helps. :)


Stitchawl
 
If you search old posts you'll see Cliff Stamp and others have used plain wax on a strop without any abrasive. One reason is to leave a protective coating of wax on the edge.
 
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