Jump to content
APC Forum

How long should you mill your BP for?


Recommended Posts

Posted

mine is not quite optimized yet but i'll add more lead as i can afford it. as is it does an admirable job in short time so i'm not in a huge hurry yet. i still need media for my h.f. 6lb. so i can run chems other than b.p. ingredients. i distrust a coffee mill for a.p.

Posted

"Ceramic" is a pretty generic term, Zirc-M is also a ceramic media but has twice the density of the white Zirc-B (generic media). While true that ceramic media CAN take longer, it WILL make a finer ground comp due to its hardness. I use Zirc-M media for *milling BP in a Model B and it takes no more than 1.5 hours to reach maximum grinding but is all but useless for grinding charcoal. I use lead filled copper pipe segments to break up the charcoal and turn it to dust.

 

Easy to make, cheap and better by far than any lead ball, no matter whom makes/sells them.

Posted

Sounds good on the Thumlers and Rebel 17 front, but I'm trying to compare them to the Hobby Pyro yellow 15lb mills with the 1 gallon pvc barrels. Do the Hobby Pyro mills need to be modified to optimize milling with the 1 gallon pvc jars?

Posted

I'm not sure if things have changed, but all the mills from hobfir on ebay have seemed more tuned for BP than actual rock tumbling. The one I had was actually from hobbyfireworks.com, but it is the same seller. Mine ran around 60rpm. I never actually measured it though, but that's ball park. All I know is that it blew my harbor freight mill out of the water, which was good enough for me.

 

Generally speaking, when someone mentions ceramic media they tend to be talking about alumina. If this is a route you intend to go down, I suggest seeking out high alumina media (90+%), which can be less prone to sparking. This is the only stuff I'd trust with live materials. If you're just milling individual chemicals, then there is less to be concerned about. There was also some surplus zirconia media available a few years ago, as Dag mentioned. It's much heavier and harder, but the cost can be prohibitive unless a deal can be found.

Posted

Sounds good on the Thumlers and Rebel 17 front, but I'm trying to compare them to the Hobby Pyro yellow 15lb mills with the 1 gallon pvc barrels. Do the Hobby Pyro mills need to be modified to optimize milling with the 1 gallon pvc jars?

 

No, the #15 PVC jars run perfectly as is. I used to sell those jars myself, they run 1 hour to make as well ground BP as possible with Zirc-M and 1.5-2 hours on ceramic.

Posted

Thanks guys..that's the info I needed.

I just thought of a flaw in my reasoning however. While the gallon jar is a good match for that 60 rpm on the Hobfir units on ebay, using my small 3 lb jars on the same unit would be turning at the same speed that I just got away from on the 6lb mill when I optimized the rollers. If I understand correctly, the smaller the jar the higher the rpm needed for optimzed milling :wacko: Eh, you can't have too many mills can you?

Posted

Actually I repurposed my harbor freight jar on the 1 gallon frame. It turns faster (75rpm?) than the 1 gallon jar. The same linear speed will turn a smaller jar with higher RPMs. I could mill batches of test compositions in about 1/2 to 1/3 the time I could on the stock HF frame.

Posted

Doh..just the opposite..gota' stop trying to think while I'm at work

Posted

Hey guys,

Is it just me or is that BP slow? My 4hr milled BP looks like it burns almost twice as fast.

 

By the way, since you're talking about mills, I'm looking to buy a better one. The 3lb is too small, it takes forever to make a 6" shell...

Which one is recommended? Been looking at Thumler's tumbler, but was concerned about it's RPM and whether it's strong enough for an upgrade.

It is, of course, a good thing if the price is not too high. 12-15lb is preferred, while 6-9lb is also of interest (as long as it's a single barrel).

Posted

Thumbler model B with the 15lb hex barrel. Rebel 17 has a same barrel. The 15lb hex barrel seems to be the most common upgrade.

Posted (edited)

Cheers, anyplace got these relatively cheap? Maybe some1 wanna sell theirs? :)

 

edit: Sorry, forgot to ask. Is that thing noisy? My 3lb is of rubber, and is still a bit noisy for me, as I got people living upstairs. Got a sound-isolated box, but it gets really hot in there(bad idea......).

Edited by enanthate
Posted

Thumbler model B with the 15lb hex barrel. Rebel 17 has a same barrel. The 15lb hex barrel seems to be the most common upgrade.

 

The Rebel 17 is a much better value for the same price ($200.00 ish) new. The high speed motor looks really good too!

Posted

Cheers, anyplace got these relatively cheap? Maybe some1 wanna sell theirs? :)

 

edit: Sorry, forgot to ask. Is that thing noisy? My 3lb is of rubber, and is still a bit noisy for me, as I got people living upstairs. Got a sound-isolated box, but it gets really hot in there(bad idea......).

 

Check ebay, I got both of mine for around $100.00 each, both are completely functional but old (1978 and 1977).

Posted

Cheers, anyplace got these relatively cheap? Maybe some1 wanna sell theirs? :)

 

edit: Sorry, forgot to ask. Is that thing noisy? My 3lb is of rubber, and is still a bit noisy for me, as I got people living upstairs. Got a sound-isolated box, but it gets really hot in there(bad idea......).

 

I believe a new 12lb all rubber hex barrel (no metal frame) can be had on Ebay for $70. The rubber lined jars and barrels are very quiet compared to the PVC equivalent.

 

Hex shaped barrels create an internal milling action similar to having lift bars in the jar.

Posted (edited)

 

The Rebel 17 is a much better value for the same price ($200.00 ish) new. The high speed motor looks really good too!

 

Looks to be avail here for ~$219 How much media would you need for this? I saw a listing on eBay for .5" lead/antimony balls ... 100 for $19.99 ... decent deal?

 

Edit: saw above that you're not such a fan of lead ball. Do you have any sourcing options for "Zirc-M" ? Also, I'm interested in your lead filled copper pipe for crushing charcoal. What are you using there (size / qty / etc)?

Edited by ChuckD
Posted

Check eBay for Zirconium-M media, it goes up every so often. Don't be afraid of dirty, old, used zirc-m either. It is non absorbant and can be easily washed.

 

The lead filled copper is easy, cut 3/4" long sections of 1/2" copper pipe. Fill with molten lead to almost overflowing, swage when cold with a 3 pound steel slege hammer with filled sections sitting on an end, not on its side.

 

Lead shrinks a lot when it cools, it pulls away from the tube walls even if we'll fluxed and tinned. The swedging allows for a mechanical bond to the walls of the tube.

 

Because of the nature of the mechanical bond, don't use this for anything but BP type comps.

  • Like 1
Posted

 

Looks to be avail here for ~$219 How much media would you need for this? I saw a listing on eBay for .5" lead/antimony balls ... 100 for $19.99 ... decent deal?

 

Edit: saw above that you're not such a fan of lead ball. Do you have any sourcing options for "Zirc-M" ? Also, I'm interested in your lead filled copper pipe for crushing charcoal. What are you using there (size / qty / etc)?

 

For the 15lb drum included with the Rebel 17 mill, you will need 35 lbs of lead media to fill halfway. IIRC, that is about 600-800 pieces of 1/2" balls. Other types of mill media like Zirc-M may be a different weight when mill jar is filled halfway. I believe the small HF 6lb jars each hold 200 1/2" lead media for correct charge.

 

Pyrocreations sells alumina "ceramic" media at a reasonable price. I have used this media for milling individual chems with great success. Sometimes the deals on ceramic/ zirconia media show up on Ebay as Dagabu mentioned

Posted

I've been using ceramic 13mm round balls. Got some new millingmedia today, 20mm ceramic cylinder pebbles.

After reading it seems that balls are good for "crushing" powders to a smaller size, while cylpebs are good for mixing the chems? What about the combination of both types?

It seems to me so far that the cylpebs makes a bit slower BP than the balls. I'll keep trying.

 

What's best for BP?

Posted

For what it's worth, I have the Thumler's Tumbler model B (thanks to the good advice of this forum). I put 1,000 .50cal lead balls in the jar. Per Mumbles recommendation, I only run it for 2-3 hours and I get very fast bp (see my video). Right now I am making about 2 lbs of bp at a time. It is a quality mill for a reasonable price. I paid 200.00 and maybe 12.00 shipping. It is more expensive than the HF mill that I was about to buy, but now that I have made several batches of BP, it is well worth the extra $$. The best part about it is that it only takes 2-3 hours to make a perfect batch of bp... so in a day, I can make 3 or 4 big batches, no problem. And at 2 lbs of bp at a time, that's some pretty serious production. I have heard that in the HF mill, you have to mill for like 6-8 hours, maybe even more. I give a big 'thumbs up' to the Thumlers Tumbler!!

Posted

braddsn, sounds like it's well worth the money. It costs about a $120 extra to get it here (shipping and taxes), but I will make the investment as soon as I can.

2lbs of bp in 2-3hours is insane, I'm used to 100g in 6hours lol.

 

How's the noise? As long as it's running for 2-3hrs at a time, noise isn't a big problem. Just curious.

Posted

If you can hear it running while inside the house relaxing, it's way to close :)

Posted

enanthate, the Thumler's unit is extremely quiet. Mine is about 50 yds from my house, and if I am standing outside and it's quiet, I can barely hear it. Sounds like a very quiet washing machine when its running... lol. Wow that is some expensive shippinig man! Hate to hear that. But now that I have the unit, I can't imagine making black powder in a little 6 lb jar. This thing is awesome. Made another 2 lbs this evening. :)

Posted

You can get the model b off of ebay for about $100.00 each if you are patient.

Posted

Wait, so you all mill your bp outdoors? I knew some of you did, but some are milling indoors too, right? Mine is next to my livingroom, hence the noise-issue..

 

This reminds me to do a little safety-check with you guys. I store everything indoors, as I have no other place to stash it (nope, nowhere). Stars are well separated and stored in a large box, same goes for bp on hulls, lift, etc. Flash and whistle are only made and used when needed.

Am I crazy? I hope not, cause if this is crazyness then I would have to quit this hobby. Dont want that. Dont want that....

×
×
  • Create New...