Ball Mills
#421
Posted 28 September 2006 - 09:44 PM
That's a lot of BP - stay green!
#422
Posted 28 September 2006 - 10:16 PM
Hi friends,
I told my Al-foil-milling-story before and here is another result:
I sieved the resulting powder a,d found that approx
25% are bigger than 50 mesh
25% are bigger than 150 mesh and
25% are bigger than 325 mesh.
The fourth 25% are -325 mesh.
I dont have a sieve finer than 325 mesh but I hope the -325 mesh fraction will be good enough for flash. The particles will be very flat flake shape so the chance is quite good.
MfG
newtoolsmith
That's a useful spread of particle sizes and in flake form too.
I haven't milled metals yet I need to get some accurate mesh and try milling some magnalium (engine casing, so 5-10 Mg I guess). It is fairly brittle so should mill well.
Your mill is elaborate and impressive, looks really well built. I could do with a decent DC power supply like that for mine.
#423
Posted 29 September 2006 - 01:02 PM
at a rough estimate, 1kg at a decent speed.
Could do up to 1kg if it was given enough time. Using Lead instead of ceramic would speed things up a little, as it is 3 time more dence than ceramic. Still at optimum speed you can only realistically get 400g per 3L of milling jar volume. You can get more at the expence of time in the mill. It is inportant to not clog up the mill; if too much is put in the mill will not be very efficient at all.
My 3L mill makes 400g of good quality bp in a little under an hour (with ceramic media), 3 hours and it produces a flour like consistancy. From experimentation I found that just adding an extra 100g takes the mill time up to over 4 hours; four times longer is not that optimum. In that four hours I can make 1.5kg rather than one batch of 500g.
#424
Posted 29 September 2006 - 02:37 PM
I remilled the coarsest particles (+50mesh) and the yield of the -325 fraction is some bigger now.
The -50+150mesh will be used for rockets to give a nice tail. This is not tested yet because I had to do other things (look at the Perchlorate thread).
Some days ago I made a few kg MgAl - it was very easy - and I milled it after crushing it into pieces.
I didnt sieve the resulting powder yet but I guess nothing is over 50mesh, only a little -50+150mesh and most will be -325mesh.
I dont have a sieve finer than 325mesh but I hope it will be fine enough for flash.
MfG
newtoolsmith
#425
Posted 20 October 2006 - 12:15 PM
Regards,
Drew
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Drew's World - http://drews-world.co.uk
Pyro World - http://pyro-world.co.uk
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#426
Posted 21 October 2006 - 08:40 PM
#427
Posted 22 October 2006 - 10:51 AM
Regards,
Drew
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Drew's World - http://drews-world.co.uk
Pyro World - http://pyro-world.co.uk
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#428
Posted 22 October 2006 - 10:29 PM
Do you know whether theres much difference in the plsatic ones compared to the rubber ones? (i found that the plastic ones will require rubber bands for grips and they tend to slip when a heavier load is put in)
#429
Posted 23 October 2006 - 02:11 PM
I managed to quieten my mill a little very easily, a 100mm thick foam block underneath it really reduced the sound transmission.Is the sound insulation effective? Mine is LOUD!
newtoolsmith:-
Glad you've had some success.
MgAl is amazingly easy to mill, I milled some engine casing shavings this week and it milled to below 100 mesh in 12 hours (with 5% linseed oil). I dried it over gentle heat (~100deg.C) and it burns beautifully bright in a fountain.
Unfortunately, making small enough chips to mill, using a drill and rotary rasp, is very time consuming.
I'm currently trying to work out an efficient method for milling PVC and Sulphur, the elastic properties of both don't help.
#430
Posted 23 October 2006 - 04:32 PM
I managed to quieten my mill a little very easily, a 100mm thick foam block underneath it really reduced the sound transmission.
newtoolsmith:-
Glad you've had some success.
MgAl is amazingly easy to mill, I milled some engine casing shavings this week and it milled to below 100 mesh in 12 hours (with 5% linseed oil). I dried it over gentle heat (~100deg.C) and it burns beautifully bright in a fountain.
Unfortunately, making small enough chips to mill, using a drill and rotary rasp, is very time consuming.
I'm currently trying to work out an efficient method for milling PVC and Sulphur, the elastic properties of both don't help.
Is your magnalium 50/50? I'd never be able to get shavings off mine, just too brittle.
#431
Posted 24 October 2006 - 06:12 PM
Regards,
Drew
I ordered the exact same rock tumbler actually, though i ordered the plastic container instead- simply because i already have a rubber one from a previous tumbler. havent been able to mill anything yet as my ceramic media still havent arrived from inoxia yet.
Do you know whether theres much difference in the plsatic ones compared to the rubber ones? (i found that the plastic ones will require rubber bands for grips and they tend to slip when a heavier load is put in)
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Drew's World - http://drews-world.co.uk
Pyro World - http://pyro-world.co.uk
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#432
Posted 24 October 2006 - 06:50 PM
I've been using good ole U.S. of A currency discs for that purpose for the last five years with nary a problem. The nickel and quarter denominations work very well. They don't spark; They are about impossible to wear out, and they're cheap. I use 12 quarters and 20 nickels to mill 100 grams of lift in about 3 hours. The coins cascade in landslide fashion down the inside the tumbler and provide a shearing/rolling action to the mix.
I mill the charcoal and potassium nitrate for 2 hours and add the sulfur for the last hour. After pressing, corning, and screening, my lift BP is as good as any commercial product I've tried. My milling tumbler is an ancient '70s model Thumblers Tumbler with a rubber jar of about 3 pounds capacity. It is soooo-- old I had to replace the jar and sealing ring last month, the motor let go about 1986 and I replaced it with a continuous duty rated fan motor which continues to grind on and on.
And here’s yet another variation on charcoal sparks from Flint Hapirat for all ye tropical pyromaniacs. Thankee, Flint."
article
I was wondering if this would work? or should I just use brass?
#433
Posted 24 October 2006 - 07:00 PM
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Drew's World - http://drews-world.co.uk
Pyro World - http://pyro-world.co.uk
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#434
Posted 24 October 2006 - 07:33 PM
It is in the region of 10-15% Mg as far as my investigations have uncovered, pretty typical of the alloys used in engine casings (injection casting I believe) of the time.Is your magnalium 50/50? I'd never be able to get shavings off mine, just too brittle.
It is brittle and breaks pretty easily with a small hammer (even easier in a crash ) but only down to 1cm pieces, so I drill it. Love to know an easy way of processing it.
Good for fountains etc. but have decent commercial grade for demanding applications.
PM me if you want some to compare!
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