How many hours do you ballmill your BP?
Posted 04 April 2017 - 02:30 AM
- pyrohacker likes this
Posted 06 April 2017 - 01:30 PM
You may try breaking your pucks when they are still 'wet'. Letting them fully dry makes them tougher and harder to break up. They are still plenty hard with the few percent of water but they take a lot less effort to break apart right after pressing than letting them dry.
Dave F - I would be really interested in hearing what kind of flight times you got with the FPAG shuttle, even if it wasn't your favorite tester. I like the concept of being able to compare BP but never found many people sharing their results, even as a member of FPAG (though I'm not the most social butterfly in the world). I did notice the shuttle would 'wag' a bit but don't remember anything too extreme and I always averaged multiple shots to get a result and didn't notice to many large time variations and didn't think much of it. But if you still have your longest flight time using 4g of BP I would love to know assuming you have them and not too hard to track down.
- MudDuckPyro79 likes this
Posted 06 April 2017 - 07:03 PM
Posted 06 April 2017 - 07:04 PM
FlaMtnBkr, here are my results from the original BP testing I did with the shuttle tester. I got it from Ned. It was called a 'dongle' at the time. I don't know if it was identical to the FPAG tester or not. All my tests used 4.0 grams of powder or friable granules. I realize now that the mill dust tests were pretty much useless, but I included them for posterity.These results are years old and my note-taking stinks. When I first started out, I was using ceramic media. The media for all these tests was probably .780" diameter cylinders. It's possible I switched to mixed sizes by the time I got done this round of tests. I don't recommend ceramic for this purpose.
1) 8 hour milled willow-based red gum BP, per Ned's instructions- 7.0 seconds
2) 3 hour sumac BP with 1 1/2% wax- 6.6 sec.
3) 3 hour willow BP with 2% wax- 6.5 sec.
4) 3 hour willow BP 7:1 on rice hulls, 6.4 sec. I may have used more than 4 grams to account for the rice hull weight.
5) 3 hour alder pellet BP with 1 1/2% wax- 5.4 sec.
6) GOEX Fg- 4.9 sec.
7) 3 hour willow BP milled with 2% wax as fine shavings, tested as powder- 4.5 sec.
8) Same powder as above, granulated with water- 5.5 sec.
9) 3 hour willow BP with 2% shaved wax, then riced with lacquer thinner- 6.4 sec.
10) Same powder as above, riced with water- 5.5 sec.
11) Same powder as above, after drying more- 5.9 sec.
12) Willow BP, 2 hour mill, granulated with alcohol only- 7.2 sec.
13) -20 mesh red oak, pre-milled 4 hours, then milled as BP 3 hours, granulated with alcohol- 6.6 sec.
14) Same powder as above, but the BP mill time was doubled to 6 hours- 7.1 sec.
15) -20 mesh balsa charcoal milled 1 hour, then milled as BP 4 hours, riced with alcohol- 6.9 sec. Shuttle wobbled in flight.
16) Same powder as above on a very still day- 7.7 sec.
17) -20 mesh clear white pine charcoal milled 4 hours, then milled as BP 4 hours- 4.9 sec. Probably mill dust was used.
18) -20 mesh Castor plant stalk charcoal milled 4 hours, then milled as BP 4 hours- 5.4 sec. Probably mill dust was used.
19) Old willow charcoal, milled as BP 4 hours- 8.2 sec. No other details. Charcoal was likely milled 4 hours, BP was likely riced with alcohol.
These mill times are excessive, and the media used was the least efficient also.
Edited by DavidF, 06 April 2017 - 11:16 PM.
Posted 06 April 2017 - 11:19 PM
OK, I fixed it. I should have clarified, since I've been talking about baseballs mostly.
Posted 11 April 2017 - 09:52 PM
I have a Rebel 17 jar with 35# of 1/2" spherical lead media. I mill 500g of my ERC pet bedding charcoal for one hour, stopping once in the middle to clean the area around the lid.
I mill 882.4g of greenhouse grade nitrate and 117.6g of slightly gritty sulfur together for an hour, again stopping once in the middle to clean the grit out from under the lid. I screen that sulfur/nitrate mix through a 100 mesh and toss what little refuses to pass through it.
I take 85% of the sulfur/nitrate mix, and 15% of the charcoal, add some dextrin (still playing with amounts there), then sieve everything twice through a 40 mesh and once through a 100 mesh. Wet with 7:3 isopropyl alcohol until very soft dough, then granulated through a 4 mesh. Graded -4 +8 mesh "2FA." The results speak for themselves.
These first tests were with no binder. I'm now working on slowing it back down and hardening the grains up, since they are quite fragile.
And here are some tests with dextrin. All 10g shots.
Keep in mind that the "old stock" and "6hr milled" powders have served me well for lifting all of my cylinder shells up until this point. That's the power level I'm shooting for.
So, I guess the point is that if you make 3 component milled powder, but don't care for the inherent danger of it, you don't need anything different from what you already have to make screen-mixed powder. You'll probably want a 100 mesh screen if you don't have one already, but those are cheap: https://www.amazon.c..._i=desktop&th=1
Edited by Wiley, 12 April 2017 - 11:02 AM.
- Wiley likes this
Posted 15 April 2017 - 04:03 PM
This is what comes of pucked and corned. If it's clear enough look at how the grains are all pretty consistent thus is why I do it thus way.
Can you give a few more details of your methods please? I mean about the process to obtain the granules out of pucks until they are granulated.
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