Milling Mg & Al
#46
Posted 17 October 2005 - 09:56 PM
#47
Posted 18 October 2005 - 03:16 AM
I found this interesting page on grinding metals with a grinding machine. Those machines have similar construction to a ball mill and I suppose it wouldn't be too hard to build one.
http://members.shaw....er/grinder.html
Thanks for that interesting link ! Be careful with this, but it sounds like a great way to eliminate some source problems. If I do try it, I will be certain to follow the advice re: adding dichromate to the water for Mg, and the Boric Acid for the Al. Of course, then comes the potential to slop toxic liquid around the work area. If you get the chance, read Lloyd Sponenburgh's addendum to his latest edition of his excellent book on ball mill construction and usage. In a nutshell he experienced a pyrophoric reaction while using a mill to mix (with no grinding media) 2 micron Mg and Cabosil, which although no flame touched him, took much of the skin off his left arm, and the side of his neck and face just from the UV flash. BE CAUTIOUS.
KAABLAAAMMM!!!
"OK... that shows you what could potentially happen."
--Homer Simpson
#48
Posted 11 December 2005 - 01:28 AM
The first thing that strikes me with this thread is the use of metal milling media, which I consider a very bad idea, you get all sorts of weird reactions going on at a bimetallic surface, due to different ionisation energies, electron affinities and stuff like that. So my first piece of advice is, unless you understand the chemistry, use inert materials, such as ceramic balls a non-metallic jar.
My inexperience of milling aluminium is:
Aluminium - Tesco foil that has been shredded into strips.
Media - 20 mm alumina ceramic balls
Jars - HDPE, 3 Ltr and 15ltr
3ltr jar:
I have used this jar for about six hour mills at a time, mainly with the intention of producing fake powders in the 10-120 mesh range for use in fountains, however there is inevitably some finer powder, which we graded as <400#. This 400 mesh powder was tested in the 70:30 ratio with potassium perchlorate to form an acceptable flash powder. So, if nothing else this shows that flash grade powder can be made in a 3 litre mill jar.
15ltr jar:
This is our big mill jar that Inoxia will be using to manufacture 10-120 mesh aluminium. It eats shredded aluminium foil into a <10# powder in about five minutes. The jar managed to get about six hours milling time before my old and tird mill packed up. It is hard to see what sort of grade the powder is at because it is under the balls and I don't want to empty the jar yet.
The future:
Myself and Andrew have been working on the new mill, and with our new lathe we have turned an indestructible axle. Hopefully the thing should be up and running in a couple of weeks, we plan on doing some much-needed research into the field. I'll add a new post here if we get any new developments. I might stick a photo up of the finished mill.
Almost forgot, we have an electric crosscut shredded now, which kicks arse.
#49
Posted 05 January 2006 - 09:54 AM
I found this interesting page on grinding metals with a grinding machine. Those machines have similar construction to a ball mill and I suppose it wouldn't be too hard to build one.
http://members.shaw....er/grinder.html
A friend of me, made 2 nice metal grinders i compiled it in a pdf file, if there any questions we could open a new topic i think:
Metal grinding machine
Link: http://www.sendspace.com/file/0z7m2v
File: The Metal Grinding Machine.pdf
Size: 1.71 MB
#50
Posted 01 February 2006 - 10:10 PM
#51
Posted 20 September 2006 - 12:40 PM
#52
Posted 20 September 2006 - 02:01 PM
#53
Posted 20 September 2006 - 06:34 PM
#54
Posted 21 September 2006 - 10:42 AM
#55
Posted 21 September 2006 - 08:37 PM
I thought when ballmilling the avoidance of any possible sparks was of utmost importance,so when i read that you have tried flint pebbles Have you ever tried knocking together two pieces of flint fairly hard!sparks are the order of the day!I use a blender to shred foil. I crumple sheets of it into fist sized balls before putting it in. It quickly reduces the foil to a sort of twisted, mashed granular form. Be aware that doing this bluntens the blade, so it is helpful if you can remove it to sharpen.
I have also started batches with foil torn into pieces (about 4 or 5cm square). Since the design of the mill and media was very different then, I can't say what difference it made, but I doubt it was too significant.
BTW: I shedded the Al dry - no water, or, as I have also seen referred to, salt. the aim was just to "chop" it, rather than finely grind it.
I have used flint pebbles and large steel nuts to mill aluminium, with effectiveness increasing in that order. There was a silver colour on the jar and media after I milled the Al with it, but I just milled some clay afterwards, before washing it as usual, and this seemed to get rid of most of the colour.
#56
Posted 21 September 2006 - 08:55 PM
I thought when ballmilling the avoidance of any possible sparks was of utmost importance,so when i read that you have tried flint pebbles Have you ever tried knocking together two pieces of flint fairly hard!sparks are the order of the day!
Sparks only really matter when you're milling an explosive comp, that's why it's ok to mill al with steel media even though it sparks. For example, no matter how many sparks you put on charcoal, you won't light it very easy, but one spark on Bp and up it goes.
Edited by fishy1, 21 September 2006 - 08:59 PM.
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