Ed Huntress wrote:
wrote in message
...
On Jan 1, 5:33 pm, wrote:

When talking about abrasive stones what is the difference between
"Arkansas" and "India" stones?

Thanks in advance.



Arkansas stones are natural products, mostly quartz, finer grain than
the finest India stones. India stones are a man-made product, mostly
aluminum oxide. You can get a finer surface finish with an Arkansas
stone, they cost more and good ones are getting scarce, particularly
the black(super-fine) variety. Right now, I use diamond hone plates
for moving a lot of metal, ceramic hones for finer work, I save the
black Arkansas for producing the very finest finish. Arkansas stones
need oil for removing the metal from the pores, they're a bugger to
clean up once the surface is plugged up and doesn't cut anymore.


If you're brave, put them in a oven at 250 - 300 deg. F until the old oil
appears on the surface. I leave them in for half an hour up to an hour. Wipe
quickly with an old towel. Don't tell your wife what you did to her oven.


I haven't got a wife to worry about but that does sound like a very
good excuse to get a a small or even large temperature controlled
furnace. I have 2, a small muffle furnace with about a 6" x 6" x 5"
chamber and a 18" ID ex pottery kiln which I had in use today to dry a
pre-fire some insulating castable.
This works for Indias and Crystolon stones, too. If you're not brave, soak
in warm kerosene for a week and then wipe them off. It's not as effective
but it's better than nothing.


Ceramic stones can be cleaned with water or used with oil, India
stones are best used with oil but they can be used dry. Arkansas
stones come in three varieties, Wa****a(coarsest and softest),
white(fine and hard) and black(hardest and finest). The deposits in
Arkansas are playing out, it's hard to find a stone equivalent to what
you could get 20 years ago. Most of what is sold as Arkansas stones
these days would have been graded as Wa****a back then and pretty poor
ones at that. It's hard to wear a white or black one out, usual
problem is they get dropped or chipped. This is a real problem when
you depend on that stone's edge being sharp and straight for stoning
sear notches. I usually keep mine wrapped up and boxed when not in
use and don't leave them on the bench. Ceramic stones are a good
substitute, just not quite as fine as a black Arkansas, not as
expensive, either.


Norton sells a nice big translucent Arkansas for just $180...

Except for a light-gray translucent (my finest) and a black surgical (almost
as fine), my newest hard Arkansas stone is around 60 years old. I have six
or seven flat ones in various sizes, five or so hard Arkansas slips in
tapers and rhombics, and a dozen or so Wa****as, and they're all as flat as
new. It's a long-term investment -- if you don't drop them.

--
Ed Huntress