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Thin rectangle brass scraps as milling media


SignalKanboom

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I have long brass scraps that are a 1/4 Inch thick and anywhere from an 1/8in-1/4 inch wide and all are 1/2- 1 inch long. I wanted to use these as media. They are heavy and jagged, being that they are rectangular, so they will only tumble. I think it will be like blade/ball milling at the same time.

 

Does this sound like a suitable media?

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Maybe. Just hope those jagged edges don't shred the inside of your mill jar... I'm trying to mentally compare the mass of one of your typical pieces vs a .50 caliber lead ball, and seems to me they might be kind of light. Most powder milling is from compression/impact, not tearing.

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The brass might be just the thing for your charcoal. Maybe you can use some grit to wear the edges down before you use it for charcoal. Otherwise, you'll have a lot of little shreds of brass in your charcoal. Washing the media of grit before using it for charcoal would be good. I've had the flecks when I used cylindrical media, but they were no problem with BP-based mixtures. The amount was vanishingly small though. The cylindrical brass media I used was 5/8X5/8 and 3/4X3/4", with bevelled edges, which became rounded. In a 6" diameter mill jar, this media was too large for creating fast powder most efficiently. Some folks use lead cast into pieces of 1/2" copper water pipe, but I think that media is too large as well. Myself, I'd never use media larger than 1/2" diameter nowadays.

 

Once the edges are worn down, your brass pieces will probably be fine in a PVC jar, but a rubber jar with a larger diameter would be desirable. Ned Gorski has radius-ended small SS cylinders, and he likes the 'sliding' action they have. Maybe your brass will behave similarly. It's worth a try. Somebody posted a price for brass spheres a while back that was the cheapest I'd seen. As I recall, it would have made great milling media.

 

One curious thing I found when using yellow brass to mill charcoal was that the charcoal would change the color of the surfaces of the brass media in different ways, depending on what charcoal was being milled. Mostly, the yellow color was changed to white/yellow.

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Thats interesting about the color changes Justliving. Shark I was debating about running them in a crappy jar with some kind of abrasive to smooth them out. I will for sure be grinding and sanding them to smooth sharp edges because I had to actually cut these into the desired sizes. They range from significantly heavier than the lead balls to much lighter. I want a mix because I have found that smaller media mixed with larger media is more efficient. As it stands it is anecdotal At best , but I will provide concrete evidence through some sort of experiment. I ran 3/8 and 1/4 inch sling shot SS ammo with my hardened lead antimony media 1/2 inch and it was a very quick milling time. The charcoal/sulfur passed through my screen 60 mesh much faster than usual. This could be due to volume differences in the jar with more media in total. Im going to try the brass chunks after doing some work on them. I will report my findingS on that first and foremost.
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Ultimately its the milling not the mill that you want right, so there may be other possibilities for mills and media. However it's usually best to try to follow previous best practice and develop that into your style.

 

However I'd suspect that a mass of brass would cast well into spheres or short rods.

 

One of the issues with a mill is mill jar life and another is mill noise. If your mill is rattling brass bar for four hours expect repercussions.

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I tend to favor smaller media as well. It does have some advantages. Smaller media means more balls per unit volume or for the same mass of media. More media means more impacts and generally faster milling. The disadvantage is smaller media has less mass. This tends to mean less crushing powder. If starting with finer materials, I've always found that the faster milling outweighs the less efficient crushing/grinding. I used to use 000 buckshot for media. It's around 3/8" in diameter and gave great BP, if you started with something around table salt or smaller materials. It had some trouble with larger or harder chunks of charcoal.

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I tend to favor smaller media as well. It does have some advantages. Smaller media means more balls per unit volume or for the same mass of media. More media means more impacts and generally faster milling. The disadvantage is smaller media has less mass. This tends to mean less crushing powder. If starting with finer materials, I've always found that the faster milling outweighs the less efficient crushing/grinding. I used to use 000 buckshot for media. It's around 3/8" in diameter and gave great BP, if you started with something around table salt or smaller materials. It had some trouble with larger or harder chunks of charcoal.

Thats awesome, I like it when I post something and someone knowledgeable confirms it.

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