PyroGb Posted February 19 Posted February 19 I finally got the necessary items and made a batch of bp. IMG_0786.MOV
SharkWhisperer Posted February 20 Posted February 20 Great start! Looks like it'd perform well for most purposes. Details on charcoal, milling & granulation (or corning)? A common theme with folks new to fireworking is "why is my bp so slow?". Maybe your experiences will be useful to others.
PyroGb Posted February 20 Author Posted February 20 Thx I have been working on my bp it for a while. basic 75-15-10 I used spruce charcoal (I have a few questions about that) which I pre milled before mixing the chemicals and putting in mill, I used Marbles as media, then I let it go for about 12 hours overnight. Once done I added 50-50 iso / water and pushed through a sieve to granulate. I will do another test later, I did this one about an hour and a half after the granulation with a fan on for drying so I’ll let it dry more.
PyroGb Posted February 20 Author Posted February 20 Not completely sure if I did it right but I did a test for burn rate at 3 inch 30fps and it took 10 frames so burn rate of 0.3 sec per inch.
SharkWhisperer Posted February 20 Posted February 20 16 hours ago, PyroGb said: Thx I have been working on my bp it for a while. basic 75-15-10 I used spruce charcoal (I have a few questions about that) which I pre milled before mixing the chemicals and putting in mill, I used Marbles as media, then I let it go for about 12 hours overnight. Once done I added 50-50 iso / water and pushed through a sieve to granulate. I will do another test later, I did this one about an hour and a half after the granulation with a fan on for drying so I’ll let it dry more. Nice. Collected spruce limbs or "SPF" (spruce/pine/fir) lumber from the store? Folks might give you grief about marble milling media. Supposed spark potential, especially the colored ones with metal pigments. Plus, marbles are way less dense than other media options that might give you better integration in a shorter mill time. BP can take longer to dry, so you might see increased burn rates with more drying. After a day in the sun I store BP sealed with a silica packet to collect remnant moisture (there's always some remaining for me). I granulate with 70% IPA for fast drying time (lazy about waiting), but let my 'dough' rest for an hour or longer to give it time to really permeate. I do the same with dextrin-containing BP meant for tougher lift/burst BP, too--to give the little bit of water in 70% IPA sufficient time to contact and activate the dextrin. Hard to tell but your grains look roughly 3Fg sized--you might want to use a larger screen size and then sieve your granules into various size grades for different purposes. Your current size is probably appropriate for use in smaller shells (eg, <3 inches). Once you have your speed worked out, try to achieve consistency from batch-to-batch. Easiest to do if you have a sizeable quantity of the exact same proven charcoal. Overall, though, great start!
SharkWhisperer Posted February 21 Posted February 21 1 hour ago, Richtee said: Plus, you don’t have to bust it up, right Shark? Oh man...RichTee collected himself some prime willow for banging-hot charcoal and it makes ass-busting BP for sure, but he insists on corning into max-density 2.7-2.8g/cc pucks. That's fantastic if you're volume-restricted (like in cartridge firearms), or for tossing big shells when you don't want to pour/attach a liter+ bag of low-density granulated BP to a shell, but man-o-man, try breaking that up into smaller granules for typical hobbyist uses. Sheesh! The 50-lb bags of FA blastiing/fireworking coal are all corned/broken apart, too. So's the lift in cheap Chicomm shells... Now you can typically beat on BP all day with a hammer without worrisome consequences, but BP pucks are hard to break down, even with a friggin hammer. You need a grinder of some sort. What do you use, RT? Running low on B metal I use for rocket motor igniters so poked around. Got a quote for around $3500 for a kilo of amorphous B powder, oh my! Yeah, it's probably worth a few bucks, but not that crazy rate. In common use in military pyrotechnics. Propellants and delay charges. Pretty green flame. New research being done on B-Mg2 alloys and others will be interesting. Many articles fro J Pyrotechnics et al are open-access and available for free online.
All10Fingers Posted February 21 Posted February 21 I grind my pucks with a ceramic burr coffee mill. I find using a hammer produces thin flakes that are still easy to break. Then use a "classifier" set made for use in gold panning. It'll send a shell to the moon if I wanted to
PyroGb Posted February 21 Author Posted February 21 CHNO I needed a way to video the bp burning and I didn’t have fuse on hand… or a tripod… or freinds…🥲 nah but how would you suggest to light it consistently for burn tests?
PyroGb Posted February 21 Author Posted February 21 So about charcoal. I live on a farm so I just chopped up small pieces of spruce kindeling I’ve heard Willow is fantastic so I might go on a search for some, unfortunentaly I have all birch and spruce.
PyroGb Posted February 21 Author Posted February 21 10 hours ago, All10Fingers said: I grind my pucks with a ceramic burr coffee mill. I find using a hammer produces thin flakes that are still easy to break. Then use a "classifier" set made for use in gold panning. It'll send a shell to the moon if I wanted to Also about pucks I’m new to this and have not had experience with it. is it for storage? Or pressing the water out?
PyroGb Posted February 21 Author Posted February 21 20 hours ago, SharkWhisperer said: Nice. Collected spruce limbs or "SPF" (spruce/pine/fir) lumber from the store? Folks might give you grief about marble milling media. Supposed spark potential, especially the colored ones with metal pigments. Plus, marbles are way less dense than other media options that might give you better integration in a shorter mill time. BP can take longer to dry, so you might see increased burn rates with more drying. After a day in the sun I store BP sealed with a silica packet to collect remnant moisture (there's always some remaining for me). I granulate with 70% IPA for fast drying time (lazy about waiting), but let my 'dough' rest for an hour or longer to give it time to really permeate. I do the same with dextrin-containing BP meant for tougher lift/burst BP, too--to give the little bit of water in 70% IPA sufficient time to contact and activate the dextrin. Hard to tell but your grains look roughly 3Fg sized--you might want to use a larger screen size and then sieve your granules into various size grades for different purposes. Your current size is probably appropriate for use in smaller shells (eg, ❤️ inches). Once you have your speed worked out, try to achieve consistency from batch-to-batch. Easiest to do if you have a sizeable quantity of the exact same proven charcoal. Overall, though, great start! About the marbles I am useing pure white ones for like art or something and a rubber barrel but i plan on switching over soon.
SharkWhisperer Posted February 21 Posted February 21 1 hour ago, PyroGb said: Also about pucks I’m new to this and have not had experience with it. is it for storage? Or pressing the water out? It serves a few purposes. Hard particles that are resistant to erosion from getting banged around, moved, so 3Fg stays 3Fg and not 4Fg, and higher-density particles contain more energy volume-to-volume than screen-granulates. This has various benefits for example when a firearm cartridge (or fireworking device) is filled to the brim--you'd never be able to load the same energetic amount by mass with less-dense granulated powder. Lower volumes for shipping/storage, too. Try out screen-granulated sometime and see how you like it. For tougher particles for lift/burst screen-mix (or mill) in dextrin before wetting. 5% is common but I typically use around 3%. Binders like dextrin are not needed in corned BP because the pucks and ground particles are tough enough to start with from the compression. Corned BP is typically 1.7-1.8g/cc. Never measured it but granulated is way less dense.
Richtee Posted February 27 Posted February 27 On 2/20/2024 at 10:00 PM, SharkWhisperer said: Now you can typically beat on BP all day with a hammer without worrisome consequences, but BP pucks are hard to break down, even with a friggin hammer. You need a grinder of some sort. What do you use, RT? I'm still figgering that out I have used a hammer, a baseball bat that fits in a PVC collar, a grain grinder. I think the grain grinder (better than the one I have) my be the answer. Wrap in paper whack with hammer, chunks into grinder. with my shitty grinder I recover about 65% by weight in grains. Rest goes back into the press. Yeah, I think a good grinder would ge to 80%+ grains.
Richtee Posted February 27 Posted February 27 On 2/21/2024 at 11:53 AM, PyroGb said: So about charcoal. I live on a farm so I just chopped up small pieces of spruce kindeling I’ve heard Willow is fantastic so I might go on a search for some, unfortunentaly I have all birch and spruce. Birch is prolly the better choice.
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