So I made a ball mill this weekend to start making my own powder in the future. I have read several places that people use hardcas lead balls. Is there any reason that I can't use soft cast such as Hornady round balls. I have a fair amount of them and don't mind using them for my mill
From what I understand lead will wear down much faster than other media and soft lead even faster which will contaminate the powder with lead dust.
I have used nickels with good results. They don't spark. Just mill a few hours longer. I now use hard lead from wheel weights in .60 caliber (it was the only mold I had at the time).
At least 6 hours with a harbor freight double drum at regular speed if all ingredients are already powdered. I just use one drum though. I plan to speed up the mill a bit by putting layers of heat shrink on the driven shaft. I think the regular speed is too slow. It works, but could mill faster I think.
The soft lead balls will work just fine. They won't last as long as harder allow will;but, they will get you going until you can get some harder ones cast. Even with the soft lead, the amount of lead getting incorporated into the powder is pretty minimal. What I generally do is mill the KNO3 by itself for 6 hours using steel ball media then mill the charcoal/sulfur mix for 6 hours again with steel media. Combine the KNO3 and charcoal/sulfur and mill for 4 hours using lead media.
If you have a harbor freight ball mill, this is a good read. The mill runs about 60rpm, but is best about 80rpm. I plan to do this. https://www.skylighter.com/blogs/how-to-make-fireworks/quick-easy-black-powder-ball-mill
1/2" copper tubing filled with lead and cut into 1" pieces. Corners anf surface area are more than round ball.
Here are two sources with suitable ball-mill media in stock: https://www.pyrocreations.com/ball-mills-and-media https://unitednuclear.com/index.php?main_page=index&cPath=25_35 Hardened lead balls (1/2 to 1 inch) are the overall best / safest for milling black powder according to this info: https://www.skylighter.com/blogs/fireworks-information/ball-milling-media
I found a couple hundred 429 Keith bullets cast from very hard lead that I decided I'd never use. Figured the sharp edges would work well.
I was thinking about brass because I know it won't spark. I also thought about marbles since it's glass but I've read some people say they can spark in some people say they can't.
Did you determine the critical speed rpm of your drum and set an appropriate milling rpm based on that? If not, you could be wasting your time. I know you don't have the HF mill, but for example (and as in the link I posted earlier), the critical speed of a HF drum is 133 rpm. That's when centrifugal force keeps the balls stuck to the edge of the inner surface of the drum, and no milling will happen. 50% to 70% of critical speed is pretty much where to be. So, at 60 rpm (factory set) the HF mill is only running about 45% of critical speed. It should be running about 80 to 90 rpm to be optimal. That is why so many people run their mills for a long time to get a fine grind when it should only take a couple of hours. I'm guilty of that as well. Several years ago I wrapped duct tape on the spinning shaft in the right places and my mill speed ran about 73 rpm which is 55% of critical speed. The tape worked but it's tedious to apply and measure, and it loses shape over time. I think I can do better with plastic tubing as per the link I posted.
After reading about people doing this to make media it hit me that .45 caliber FMJ bullets were pretty much the same thing. Since I reload for my modern guns I already had those on hand, and that's what I've been using with good results. I run my unmodified HF tumbler for 8 hours using ingredients that are already in powder form.
I did actually just test my mill. it's rotating at 41 rpm. It is slow but my motor is a veriable speed drill at only 1/2 trigger pull. I'm still in the development stage you could say. It's pretty much functional. I need to put some shields on it to cover up the motor in case of spillage so nothing has the chance to ignite. I could turn it up some more. And I'm sure I will when it comes time.
I think I'm going to order from sky lighter for my ingredients in powder form. I don't reload but that's sounds like a good media for a mill. I'd really like to use marbles but I keep hearing too many conflicting stories on if they spark or not someone suggested nickels and that don't sound too bad.
Marbles are very light weight compared to anything metal, and especially lead. I'd be afraid that marbles would increase milling time quite a bit. They may tend to "float" in the media rather than mill. ? I'm not sure how they could spark. ?
Not sure if I have posted this here yet but this ball mill is working well. I use hard lead/wheel weights.
