[BProckets] Should I Sell Ceramic Milling Media on Ebay?

[David Sleeter]

Hi Folks:

This post was inspired by a thread on the new Bprockets mailing list in
which the correspondents expressed concern about the safety of using ceramic
milling media.

As the author of "Amateur Rocket Motor Construction", and looking for a more
effective milling media than the homemade brass pellets described in my
book, about 5 years ago I did quite a bit of research on ceramic media, and
based on talks with one of the manufacturers of the 90% alumina media
(Coors), I ordered a sample of their 1/2" dia. 90% alumina pellets.

Concerned about sparking, I took 2 of the brand new pellets into a closet
and closed the door. Then, holding one pellet in each hand, I struck them
together as violently as I could. To my disappointment, the impact generated
a faint, purple colored spark. When I asked the Coors tech support expert
about this spark, he assured me that it was NOT an electrical spark, but a
photon.

In a conversation that lasted about half an hour he explained that, when
THEY first saw this "spark", they were VERY surprised and concerned. They
make these pellets in sizes up to several inches in diameter, and they sell
tons and tons of them to the grain-milling industry. The slightest chance of
a spark causing a grain mill explosion would render the entire product line
unuseable, so they sent a sample to a physics lab where they were subjected
to EXTENSIVE testing.

The lab determined that the observed "spark" was indeed NOT an electrical
spark, but a photon of an energy WAY below the threshold needed to ignite
even a high energy chemical mixture. In the years since, Coors has continued
to sell them not only to the grain industry, but to people who use them in
other applications as well. I've also spoken with a person in the fireworks
industry who uses them for milling high energy fireworks compositions, and
he's never had an explosion.

On my own, I made an additional discovery that further allayed my fears
about sparking. In my OWN experiments, I could only generate the photon
effect with BRAND NEW pellets. After a few minutes of handling, just the oil
from my fingers was enough to keep the effect from occuring. And I also
found that a single mill run with charcoal or black powder (both contain
residual organics) would contaminate the pellets enough to prevent the
effect. To clarify, try as I might, I found it IMPOSSIBLE to create the
photon with pellets that had been used for a single mill run, or even
handled and subjected to the oil from my fingers. Since then I've milled
several dozen batches of black powder with these pellets, and I've been VERY
happy with the results. These Coors pellets are NOT perfect spheres. Each
pellet is actually a short, squat cylinder with hemispherical ends, a shape
that the Coors engineers determined was most effective for grinding things
to a powder.

By doing my own microscopic particle size analysis, I've found that, when
substituted pound-for-pound for the homemade brass pellets, these 1/2" Coors
pellets mill my chemicals and the Teleflite propellants about 40% faster
than the homemade pellets. Therefore I've decided to sell these pellets over
the Teleflite website, but as of this date, September 23rd, 2004, the
website is still under construction.

THEREFORE, IF THERE'S ENOUGH INTEREST, I COULD START SELLING THEM
IMMEDIATELY ON EBAY. I have about 500 lbs. of the 1/2" Coors pellets in my
storeroom, but I need YOU people to suggest what package sizes I should sell
(i.e. 1 lb., 5 lbs., 10 lbs., etc.). Of course I want to keep my prices fair
and competitive, so if someone is already selling the 90% alumina media, a
link to their website and price pages would be appreciated. Awaiting your
replies,

David Sleeter/Teleflite