Ball mill trouble, help, please.

[SharkWhisperer]

Granulating the BP is being a pill so I'll go look into how to do that better.

 

Thanks for all the input on this. I'm also going to look into the polyurethane roller covers. I can't find the size I need on ebay so I'll try contacting the seller.

 

Thanks again.

 

--HC

Granulating your BP should be one of your lesser worries--there are several decent threads here with detailed info and likely answers to any questions you have or that might arise. Appropriate moisture integration, screen size selection, and drying rate/temp are a few of the variables to keep in mind. If it's burning nicely out of the mill, it'll speed up considerably when you sort out your granulation approach. Very recently a fellow pyro "just about" had things dialed in with his BP manufacture technique but it just wasn't burning quite right--turns out it felt dry to the touch but was still pretty damp which slowed his burn; a common mistake when you're getting started and sometimes in a hurry. More common if you're in a cooler part of the world/country in wintertime. A fan/drying box (with BP protected from any possible motor sparking or overheating) might help. Plus, if all somehow goes to hell with your granules, you can just toss it all back into a bucket/bowl, re-wet it, and start over again.

 

Good solve on the mill.

[hcb]

Granulating your BP should be one of your lesser worries--there are several decent threads here with detailed info and likely answers to any questions you have or that might arise. Appropriate moisture integration, screen size selection, and drying rate/temp are a few of the variables to keep in mind. If it's burning nicely out of the mill, it'll speed up considerably when you sort out your granulation approach. Very recently a fellow pyro "just about" had things dialed in with his BP manufacture technique but it just wasn't burning quite right--turns out it felt dry to the touch but was still pretty damp which slowed his burn; a common mistake when you're getting started and sometimes in a hurry. More common if you're in a cooler part of the world/country in wintertime. A fan/drying box (with BP protected from any possible motor sparking or overheating) might help. Plus, if all somehow goes to hell with your granules, you can just toss it all back into a bucket/bowl, re-wet it, and start over again.

 

Good solve on the mill.

 

Thank you.

 

I have settled on adding in the range of 4-8% H2O (not alcohol or alcohol mix) as it helps the KNO3 to incorporate into the fuels plus it makes it compress easier. I then puck it a form with a shop press and dry it in a food dehydrator. I then crack/smash it and sort it with screens. It's kind of a pill to do it but I get very durable granules and the density is consistent. I formed a cup and rammer which, when pressed level with a measured amount of BP inside, yields 1.7g/cc. 1.7g/cc seems to be the standard density for black powder but I don't know why.

 

--HC

[justvisiting]

hcb, you might find this article from Pyrobin useful.

 

http://pyrobin.com/files/Black%20Powder%20six%20ways%20V.2.pdf

 

Here's an article that REALLY goes into detail:

 

https://apps.dtic.mil/dtic/tr/fulltext/u2/a150455.pdf

 

And another one:

 

https://archive.org/details/DTIC_ADA1002731

 

It seems to me that the density of 1.7 gives high durability of the grains, but without slowing the powder too much. Density has quite an effect on burn rate.

[SeaMonkey]

JustVisiting,

 

Thanks for the links. Interesting conclusions were reached in

each of the documents. Some questions about burn speed

have been answered.

[urbnflx]

I think you need to add some material to your drum to spread out the load across more of the tubing.