In
knifemaking, I have made an informal study of these
compounds to help me in polishing and sharpening.
Most of the information can be confusing and way
too complicated. The following is the very condensed
"Reader's Digest" version of information
that I've found. So lets get to the good stuff.
Stropping
Compounds are buffing compounds that are used in
polishing metals and/or plastics. They are abrasives.
Think of them as sandpaper with no paper.
Most
compounds are made of three mineral components,
which are listed below. They range from a super
aggressive to very mild.
All
of these mineral compounds are measured in grain
size measured in 1- 12+ microns to help separate
them in aggressiveness.
Think
like grit in the sandpaper you use, except, the
larger the number the more aggressive. In the process
of breaking down, they break apart in different
forms; round or crystalline. Crystalline is more
aggressive in its cutting of the metal on your carving
knife.
Chromium
Oxide -
Green, very hard, very small round grain that produces
very fine scratches. Use this for slow, fine, stropping
on a handheld strop. This is a finishing stropping
compound that produces a super smooth cut.
Aluminum
Oxide -
White, Hard, small crystalline grain that produces
a fine scratch pattern. Use this for faster cutting
on your handheld strops for polishing and sharpening.
This mineral is the same mineral as used in sandpaper
for smoothing wood.
Silicon
Carbide (Silica)
Black or grey, Hard, medium to large soft crystalline
grain which produces a rougher scratch pattern for
use in more sharpening than polishing. This is the
same mineral used in the black sandpaper used in
sanding metals and in the popular Scary Sharp Method.
Sometimes
you may run across white, pink or yellow compounds.
These compounds are formulas containing calcium
carbonite, calcide alumina and no aluminum oxide
(usually all white minerals) that without colored
dies put in them would not be distinguishable from
each other when laying on the bench. Some have more
of one component than the other, making it more
or maybe less aggressive.
All
of these compounds are worthless unless you can
get them to stay on your strop or honing wheel.
These Compounds are then mixed with a binder such
as Waxes (bee & Paraffin), petroleum based Oils,
petroleum greases, tallow (beef or vegetable) and
natural oils and combinations of these to produce
a solid or paste type consistency. You can add wax
or grease to fine tune the cutting ability of the
compound. Not all buffing and stropping compounds
are made of only these minerals. I've only stated
the most common. Other stropping and sharpening
compounds have diamond and ceramic pastes that are
combined with these more common abrasives.
There
are many stropping compounds that have different
elements to produce different colors and cutting
features. They are like everyone's chili recipes.
We all have one and they all are great with characteristics
that appeal to each individual.
So
how do I decide what to use? Try them out. Use the
compound that gives you the best edge the fastest
while leaving your blade clean. The widest variety
that I've seen for an unbelievably low cost is with
Southwest Metal Finishing Supply Co. in Tyler Texas.
For $9 you can supply your carving club for a year
with one bar.
http://www.swmetal.com/cart/search?category=Polishing%20Compounds
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