brad224 Posted December 30, 2024 Posted December 30, 2024 i’ve frequently read about KP burst not being appropriate for small shells, requiring significantly more confinement, etc. today i decided to try an unscientific experiment. i have some BP mill dust coated rice hulls, made with my bestest, fastest, balsa charcoal BP, milled 6 hours in a hexagonal mill container at 60 rpm, half full of lead balls, standard 75/15/10 mix, dried in my dry box. in my humble opinion, good stuff. i filled a 1.5” festival ball shell with this, hot glued it closed, inserted some visco fuse,and wrapped it with 3 pieces of blue painters tape. no spiking, no kraft tape, just the painters tape. i then did the same thing but with KP burst coated hulls. KP was made with the standard 70/18/12 formula, charcoal was balsa, and the charcoal and sulfur were ball milled in the same mill uses for the BP. the potassium perchlorate was simply screened through a 50 mesh screen to break ip clumps, then the whole recipe was screened together and coated on rice hulls. i loaded it intk ghe same 1.5” festival shell and taped it with blue painters tape exactly like the BP one described above. video’d both in the same spot from the same distance with the same phone camera. in my estimation, the KP burst version was DECIDEDLY more energetic, despite ghe obvious lack of heavy confinement. i have used both as burst on 2”. 3” and 4” ball shells but even when kraft taped exactly the same, no special confinement, the KP burst provides a significantly harder break. pretty darn scientific, huh? have a great New Year! IMG_2826.mov IMG_2827.mov
brad224 Posted December 30, 2024 Author Posted December 30, 2024 sorry for the typos. fat thumb trying to type on phone.
Foguete Posted January 4 Posted January 4 On 12/30/2024 at 4:27 PM, brad224 said: i’ve frequently read about KP burst not being appropriate for small shells, requiring significantly more confinement, etc. today i decided to try an unscientific experiment. i have some BP mill dust coated rice hulls, made with my bestest, fastest, balsa charcoal BP, milled 6 hours in a hexagonal mill container at 60 rpm, half full of lead balls, standard 75/15/10 mix, dried in my dry box. in my humble opinion, good stuff. i filled a 1.5” festival ball shell with this, hot glued it closed, inserted some visco fuse,and wrapped it with 3 pieces of blue painters tape. no spiking, no kraft tape, just the painters tape. i then did the same thing but with KP burst coated hulls. KP was made with the standard 70/18/12 formula, charcoal was balsa, and the charcoal and sulfur were ball milled in the same mill uses for the BP. the potassium perchlorate was simply screened through a 50 mesh screen to break ip clumps, then the whole recipe was screened together and coated on rice hulls. i loaded it intk ghe same 1.5” festival shell and taped it with blue painters tape exactly like the BP one described above. video’d both in the same spot from the same distance with the same phone camera. in my estimation, the KP burst version was DECIDEDLY more energetic, despite ghe obvious lack of heavy confinement. i have used both as burst on 2”. 3” and 4” ball shells but even when kraft taped exactly the same, no special confinement, the KP burst provides a significantly harder break. pretty darn scientific, huh? have a great New Year! IMG_2826.mov IMG_2827.mov Nice test, you should do a Shell test, fill it with stars and see how it goes. If you want to have an even more energetic burst you can add some flash. Test how much works better for your stars and you nailed it.
brad224 Posted January 5 Author Posted January 5 i have several built and ready to try, but i’m waiting for some nights with less crazy wind (and maybe a little less COLD!) if there are any useful results i’ll post a short video. 1
Mumbles Posted January 6 Posted January 6 I know I've mentioned KP not always working the best in smaller shells before. One big difference is that you were using milled balsa charcoal, and I typically use commercial airfloat straight from the bag. I'd bet that had at least something to do with your results. In general, potassium perchlorate based compositions are more sensitive than potassium nitrate based compositions in terms of burn rate under pressure, but when it goes it really goes.
Foguete Posted January 16 Posted January 16 On 1/5/2025 at 11:12 AM, brad224 said: i have several built and ready to try, but i’m waiting for some nights with less crazy wind (and maybe a little less COLD!) if there are any useful results i’ll post a short video. Looking forward towards your tests, I'm curious about your results.
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