Discussion:
Ball mill vs. Coffee grinder
(too old to reply)
RoCkaZ
2003-08-02 16:13:21 UTC
Permalink
Hey there,
I always used to pulverize chemicals (KNO3, Charcoal, Sulfur, etc.)
with a coffee grinder, however when i started reading more info about
making fireworks, I noticed that it is always suggested to pulverise
with a ball mill, and not a single word about coffee grinder. Why is
it so? Wich of these machines makes a better result? I'm not talking
about how long it takes, or how messy it is and so on, but the size of
the powder particles. I'm going to make some BP and other
compositions, and now I'm a little confused whether to make a ball
mill, or to get a coffee grinder. I'd like some pro et contra's for
both machines from people who have dealed with both of them, and have
something to say ;) Thanx in advance!
Paxton
2003-08-02 18:57:28 UTC
Permalink
The only difference is you cannot mill the BP mix in a coffee grinder, but
you can do the individual components. Just make sure you are using a
different mill for oxidizers and fuels. A ball mill can be used for
individual components and it can also be used to mill the whole BP mix
making it much faster.

Pax
Post by RoCkaZ
Hey there,
I always used to pulverize chemicals (KNO3, Charcoal, Sulfur, etc.)
with a coffee grinder, however when i started reading more info about
making fireworks, I noticed that it is always suggested to pulverise
with a ball mill, and not a single word about coffee grinder. Why is
it so? Wich of these machines makes a better result? I'm not talking
about how long it takes, or how messy it is and so on, but the size of
the powder particles. I'm going to make some BP and other
compositions, and now I'm a little confused whether to make a ball
mill, or to get a coffee grinder. I'd like some pro et contra's for
both machines from people who have dealed with both of them, and have
something to say ;) Thanx in advance!
Mike Swisher
2003-08-02 20:05:25 UTC
Permalink
As far as the unwisdom of grinding black powder mixtures in the average coffer
grinder is concerned, I won't dispute you, since such grinders typically have
steel grinding wheels.

However, I call your attention to Lot 128 in the upcoming sporting gun auction
to be held by Sotheby's at Gleneagles Hotel, Auchterarder, Perthshire,Scot., on
25 August 2003. The description:

"A rare Victorian gun powder grinder, of bronze construction, with spare
grinding wheels. Used by the Eley test department to produce small batches of
finely graded powder." Estimated range is £200 - 400.

The accompanying picture looks exactly like a coffee mill. Clearly Eley's (then
the world's largest sporting ammunition manufacturer) were using this device for
the indicated purpose more than a century ago!
Post by Paxton
The only difference is you cannot mill the BP mix in a coffee grinder, but
you can do the individual components. Just make sure you are using a
different mill for oxidizers and fuels. A ball mill can be used for
individual components and it can also be used to mill the whole BP mix
making it much faster.
Pax
Post by RoCkaZ
Hey there,
I always used to pulverize chemicals (KNO3, Charcoal, Sulfur, etc.)
with a coffee grinder, however when i started reading more info about
making fireworks, I noticed that it is always suggested to pulverise
with a ball mill, and not a single word about coffee grinder. Why is
it so? Wich of these machines makes a better result? I'm not talking
about how long it takes, or how messy it is and so on, but the size of
the powder particles. I'm going to make some BP and other
compositions, and now I'm a little confused whether to make a ball
mill, or to get a coffee grinder. I'd like some pro et contra's for
both machines from people who have dealed with both of them, and have
something to say ;) Thanx in advance!
aborza
2003-08-02 20:07:07 UTC
Permalink
I have a bit of experience in milling chemicals with coffee grinders. I have
used both the blade type (cheap) and the burr type (more expensive). I have
also had a little experience using a rock tumbler as a ball mill. My rock
tumbler is the little cheap one you can get from Harbor Freight ($29). I
used marbles in the rock tumbler as media.

There is no comparison. The cheap ball mill IS VASTLY BETTER but slower. The
little tumbler could be improved with media that is more dense than glass
(302 stainless, brass, lead) but the little motor has difficulty with the
load and the tub does not rotate quickly enough. The little ball mill with
marbles will take a long time but will result in true air float charcoal
given time.

The coffee mills will quickly grind down small amounts of chemicals but will
result in a variety of sizes of ground chemical when you are done. There is
no real uniformity and true air float charcoal will not happen. Also I have
burned out a couple of the blade types grinding a couple pounds of KNO3.

The result of my experiences is that I am building a more serious ball mill
in the Sponenburgh style. To me that seems the only way to go. With a little
shopping and scrounging you should be able to make the mill for less,
perhaps much less, than $60 US. The jar is another matter. I chose to buy a
Lortone 6 lb. jar for $38. It is well sealed, easy to clean. and will result
in little shrapnel in case of a disaster (it has a rubber tub). Other tub
designs using PVC are all over the net.

You can search the news groups for media advice. I bought 302 stainless and
brass balls as media. But you can make excellent media from lead tire
weights and a .50 Cal or greater muzzle loader lead ball mold. I tried the
Sponenburgh aluminum foil method of casting lead media and found it a pain
in the you-know-what and the resultant media was all over the place in size.

As we speak I am trying to make some lead ball molds from plaster of Paris.
Check out the news group for instructions on how to do this. It is a first
for me so I do not know how well it will work.

Good luck
Post by RoCkaZ
Hey there,
I always used to pulverize chemicals (KNO3, Charcoal, Sulfur, etc.)
with a coffee grinder, however when i started reading more info about
making fireworks, I noticed that it is always suggested to pulverise
with a ball mill, and not a single word about coffee grinder. Why is
it so? Wich of these machines makes a better result? I'm not talking
about how long it takes, or how messy it is and so on, but the size of
the powder particles. I'm going to make some BP and other
compositions, and now I'm a little confused whether to make a ball
mill, or to get a coffee grinder. I'd like some pro et contra's for
both machines from people who have dealed with both of them, and have
something to say ;) Thanx in advance!
Old Dog
2003-08-02 21:28:48 UTC
Permalink
Post by RoCkaZ
Hey there,
I always used to pulverize chemicals (KNO3, Charcoal, Sulfur, etc.)
with a coffee grinder, however when i started reading more info about
making fireworks, I noticed that it is always suggested to pulverise
with a ball mill, and not a single word about coffee grinder. Why is
it so? Wich of these machines makes a better result? I'm not talking
about how long it takes, or how messy it is and so on, but the size of
the powder particles. I'm going to make some BP and other
compositions, and now I'm a little confused whether to make a ball
mill, or to get a coffee grinder. I'd like some pro et contra's for
both machines from people who have dealed with both of them, and have
something to say ;) Thanx in advance!
I'm assuming you mean the modern electric rotary type coffee grinders that work
by impact with metal blades, since the older manual types could not be adjusted
to give a very fine powder by pyrotechnic standards.

Are you familiar with the "game" called Russian roulette? You are playing a
variant of that game every time you press the "run" button with a BP mixture in
a coffee mill. They do work fine for individual chemicals or most fuel-only or
oxidizer-only mixtures, and I have several I use for small-batch testing.

Also, while I don't have any solid data handy, based on working with individual
chemicals I don't think it is possible to get as fine a grind using a coffee
mill unless you are prepared to leave it running for a LONG time. I personally
don't know of any cheap coffee mills that would stand up to that sort of
treatment.

-Rich
matt wilson
2003-08-03 08:18:05 UTC
Permalink
Well I prefer to use both as a two-step process. First I put crushed
charcoal in the coffe grinder to quickly produce a medium-coarse powder,
then into the ball mill to convert to airfloat.
Post by RoCkaZ
Hey there,
I always used to pulverize chemicals (KNO3, Charcoal, Sulfur, etc.)
with a coffee grinder, however when i started reading more info about
making fireworks, I noticed that it is always suggested to pulverise
with a ball mill, and not a single word about coffee grinder. Why is
it so? Wich of these machines makes a better result? I'm not talking
about how long it takes, or how messy it is and so on, but the size of
the powder particles. I'm going to make some BP and other
compositions, and now I'm a little confused whether to make a ball
mill, or to get a coffee grinder. I'd like some pro et contra's for
both machines from people who have dealed with both of them, and have
something to say ;) Thanx in advance!
aborza
2003-08-03 16:52:39 UTC
Permalink
Perhaps I was not clear in my post on this subject. What I said was,

"The coffee mills will quickly grind down small amounts of chemicals but
will
result in a variety of sizes of ground chemical when you are done. There is
no real uniformity and true air float charcoal will not happen."

I will try again.

"Air float" is a descriptor for a substance ground so fine that it will
virtually float in the air. It is as fine or finer than dust.

All the coffee mills I have used cannot produce a UNIFORM "air float" grind.
That means that while some of a given substance ground in a coffee mill will
be very fine there will be a variety of less fine products in the completed
grind.

If you want a virtually uniform super fine grind (air float), you must use a
ball mill. Properly built with proper media and properly charged with proper
RPM of the barrel, a ball mill can produce a uniform "air float" from
virtually any substance that can be ground to "air float" fineness. This, no
coffee mill I have used can do.

A ball mill produces finer powder than a coffee mill and produces that
fineness quite uniformly as well.
Post by PyroLeo
First of all, thank you for answers. However the main question was
left unanswered (or I haven't found the answer): wich way produces a
finer powder? Thank you ;)
P.S. I am not going to mix all three components together using a
grinder, I've still got some brain left ;p
Doc Ferguson
2003-08-03 17:44:48 UTC
Permalink
And then there is cross contamination to think about. Doc
Post by PyroLeo
First of all, thank you for answers. However the main question was
left unanswered (or I haven't found the answer): wich way produces a
finer powder? Thank you ;)
P.S. I am not going to mix all three components together using a
grinder, I've still got some brain left ;p
Joel Corwith
2003-08-03 21:28:44 UTC
Permalink
Post by Doc Ferguson
And then there is cross contamination to think about. Doc
Don't you look for a bang from your coffee at 5am?

Joel. phx

The real question is does the coffee taste better from the ball mill?
Post by Doc Ferguson
Post by PyroLeo
First of all, thank you for answers. However the main question was
left unanswered (or I haven't found the answer): wich way produces a
finer powder? Thank you ;)
P.S. I am not going to mix all three components together using a
grinder, I've still got some brain left ;p
RoCkaZ
2003-08-04 10:25:21 UTC
Permalink
Thanks you all once again. Now I've got the idea, and after having
written this post, I'm going to google on making a perfect ball mill
;) And yes, I've read all your posts, just nedeed more opinions. Sorry
if that insulted those, who had already answered the question.

PyroLeo
2003-08-03 16:41:20 UTC
Permalink
Did you actually read any of the replies? I'm guessing you never looked at the
google link you were given either. I think it was pretty clearly stated that
there was little comparison and the ball mill does a better job. The ball mill
will give you a consistently fine powder, whereas the coffee mill will give you
a coarse ground mixture of sizes.

Leo
-----------------
***@omni.lt (RoCkaZ) wrote:
<<
First of all, thank you for answers. However the main question was
left unanswered (or I haven't found the answer): wich way produces a
finer powder? Thank you ;)

P.S. I am not going to mix all three components together using a
grinder, I've still got some brain left ;p
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