Reworking BP fines

[Eagle66]

I've got my BP making process pretty well worked out. By way of background, I built a one gallon Schonenberg type mill. 30# (about 1/2 Gal.) of .500 lead balls + 650g (about 1 qt)of 75/15/10 and mill for 3 hrs. I moisten the pulverone with 90/10 alcohol/water & compress it to about 1350 psi. It comes out about 1.9g/cc. I let the pucks dry, then bust them up, grind, and screen. For shooting, I want mostly -40 +70, which is pretty much the same as fffg Goex. It's shoots pretty close to Goex, too, shot over my chrono. My "4fg" is -70 +100, which I use for my flintlock pan powder. I get way more of this than I really need, but no surprise there. A bunch of -100 dust, too.

 

That's the background, but to get to the point, I want to rework most of the -70 +100 and all of the -100. My question is, should I remill it to airfloat by itself, or maybe as part of a fresh batch of powder, then moisten, etc? Or should I just moisten it again, compress it, etc? Maybe save it to make some stars?

 

Any advice would be appreciated.

 

Mark

Edited July 25, 2014 by Eagle66

[MrB]

Either way should work. I think i would just dump it in after i had moisten the new batch.

B!

[TYRONEEZEKIEL]

Just a few points of clarity.

 

1. You mill jar is the Sponenburgh jar.

2.Polverone is just granulated BP chems through a screen, not meal. Meal is what comes out of the ball mill when its finished milling.

3. You should corn your BP pucks immediately after you press them. They are much easier to crush to size and produce significantly less dust.

 

4. Make sure your empty mill jar fills to 50% volume with media, then add your BP until it just covers the surface of the media by a half inch or so (This comes to about 25% empty mill jar volume). This is the optimal charging for your mill jar. It seems like you are doing so, but just making sure.

5. As for the left overs, save them unless you need to rework it. I save all my corning dust for ramming rockets/spolettes or making BP slurry. The corning dust doesnt recompress as well when put pack into pucks. If you did want to reuse it for lift etc, just mill it again for 20 mins or so then repress

[Arthur]

If you really have too much fines then it can be lightly milled and then damped and re pressed. Remember that lots of old formulae use the fines in fountain and rocket comps. When ramming rockets fine mill dust is easier to load into tubes because it doesn't dust and get all over the place, it goes where you pour it!

[TYRONEEZEKIEL]

Arthur. Mill dust goes everywhere. Corning dust/fines is a little better at staying put. The corning dust can be repressed. I have done it a couple of times, but the corned grains aren't as strong and tend to break easier.

[Arthur]

The old formulae assume that it is corning mill dust at about 100 - 300 mesh which handles fairly nicely, Modern amateur process produces ball mill dust which is more like soot, it floats and gets everywhere.

[Mumbles]

Using corning fines is important for some stars. I've tried to use meal dust instead. It still works, but I think the effect is a little better using the slightly heterogeneous mixtures coming from corned powder.

[Eagle66]

I really appreciate the input. One of the first things I need to do is brush up on the terminology. Especially "Sponenburgh". I never seem to get his name right, which is a bit rude. As for breaking up the pucks while they are damp, I will certainly try that with my next batch. But, since I I do my milling way out in the country where there's no one around for half a mile (and have permission to set up), it may be a week or so before my next batch. I bring a book, read or do some shooting, etc. while the mill is running. I park it behind a big pile of firewood at the end of 100' of extension cord plugged into a small generator.

 

As far as making rocket motors, that may be somewhat beyond my level. I've been shooting for years, but am just starting with fireworks, so I am going to stick with small fountains, stars, & such for a bit. My wife tends to get really cranky when I blow myself up or set the shed on fire, so small steps. With reading & your help, I'll do OK.

 

With ideas from forums, etc I built my mill & some other equipment from scratch, so if anyone wants to see some pix, I'll be glad to oblige.

 

Again, thanks for the help.

 

Mark

Edited July 29, 2014 by Eagle66

[MrB]

My wife tends to get really cranky when I blow myself up or set the shed on fire, so small steps.

Thats one of the weird things with the ladies. Blow your self up, or set fire to yourself, or even just your own property, and they will never quit nagging about it. Offer to blow them up, set them on fire, or burn their property to a crisp, and they pack their bags and go home to their moms place over x-mass. And since we need them, we send flowers, and make a lot of phone-calls trying to convince them to come back. And we do need them. Who else is going to shout at us across the yard "Dinner's ready" when were in deep thought over the next change to this shell were currently making.

 

Btw. I'm currently single. Huge shock, right? ;- )

B!

[TYRONEEZEKIEL]

I'd love to see some pictures of your mill setup. It sounds like a very solid mill. That is the most important step in fireworking.

[rogeryermaw]

beats my setup...right now i have a couple of half gallon plastic jars center spindled, riding on furniture rollers and chucked in a variable speed drill run continuously by an old atx power supply. it's reliable but sooo ghetto. it has turned out about 4 lbs. of good quality powder in the last week.

i tend to keep the fines from my granulation process. like others say, it has come in very handy for many things. rockets, fountains, ect. i also use it to pack the spaces between stars and priming of all sorts.

Edited July 30, 2014 by rogeryermaw

[Eagle66]

I'd love to see some pictures of your mill setup. It sounds like a very solid mill. That is the most important step in fireworking.

I just posted pix & descriptions on the Tools & Tooling tab. "My Ball Mill"

[Shadowcat1969]

i have a couple of half gallon plastic jars center spindled, riding on furniture rollers and chucked in a variable speed drill

 

I'd say the jars running on the furniture rollers COULD build static, however the center spindle (I assume made of metal rod/bolt of some sort) should ground that.

 

The BIG issue I see is the variable speed drill. Have you looked in the side of the drill while it is running? I bet you see a LOT of sparking going on in there. That would be a very bad thing if your mill jar were to develop a leak.

 

I'd suggest trying to find some sort of TEFC motor to replace the drill.

[rogeryermaw]

you're completely correct. i don't see it as the safest design i could use. at least it's outside on the back of my property. it's roughly 90-100 feet from the house and i start and stop it by plugging the power supply in from inside the house. i'll be upgrading it as soon as i gather all the parts. the motor i have for it is a fan motor from a honda civic. the case is completely sealed.

 

on topic, i actually used a bit of corning dust today to prime a 5/8" rising tail for a 3" shell i'm working on.