Merlin Posted July 30, 2015 Posted July 30, 2015 I have used granulated BP in my 4 inch shells with a central flash bag with success. I know at some point it is advisable to switch to rice hulls. My question is if 5 inch requires rice hulls or can granulated BP work. If granulated works would it be 4-12 mesh?
Andres1511 Posted July 30, 2015 Posted July 30, 2015 Granulated BP will work as good as rice hulls, but it just consumes much more BP compared to rice hulls. It's better to use rice hulls, al they're almost as strong as BP in bigger shells.
TYRONEEZEKIEL Posted July 30, 2015 Posted July 30, 2015 I would suggest switching to rice hulls coated 7:1 when you pass 4", so starting with a 5" I would no longer use granulated BP
Mumbles Posted July 30, 2015 Posted July 30, 2015 Just to be clear, you're still talking about plastic shells, right? In the method described by Lloyd S., the black powder serves as something between a true burst, and just a flammable filler/gas generator. The flashbag does a lot of the heavy lifting. The black powder is sort of an auxiliary burst. In a more traditionally built shell, the roles are reversed. The BP is the main burst, the flash is a booster or an auxiliary bursting compound. If you plan to stick with this method of building plastic shells, I'd stick with what works. Flash and some BP intermixed amongst the stars. If you make the transition to paper shells, or what to build them more typically, then you'll need to revisit the burst. When you line the walls of the shell with stars, there is a lot of room left in the middle for the burst. You can certainly fill it up with granular BP. It's works. It's also sort of a waste in my opinion. Most people transition into coating the BP onto rice hulls or another burst media. This allows for a more efficient use of burst.
Merlin Posted July 31, 2015 Author Posted July 31, 2015 (edited) I was hoping to continue the Lloyd S. method with fives. His instructions call for a central flash bag containing 5g of 70/30 attached to the passfire tube and a total of 80g BP for the 4 inch. I have not started on fives yet but it sounds like rice hulls may be most economical. Just got to put this HF cement mixer together- been putting it off but I think if it can roll stars it could efficiently coat rice hulls. I have to confess though, as well as Lloyd S method works, I am interested in pattern shells. Got some books coming if Skylighter ever gets them in. Thanks for the reply. Edited July 31, 2015 by Merlin
clarkie752 Posted July 31, 2015 Posted July 31, 2015 Hey Merlin, I used my hf cement mixer for making bp rice hulls and it worked great. Just make sure you get most of the water off the hulls or you will have a hell of a mess. After wetting my hulls I and swinging them round and round in the pillow case I actually hang them on the clothes line for about 15 minutes before putting them in the bp mill dust. I did around 7 pounds at once and they turned out really nice. I followed neds article on fireworking.com but I think the same article is on skylighter.com to if you wanna check it out.
TYRONEEZEKIEL Posted July 31, 2015 Posted July 31, 2015 If you make the transition to paper shells, or what to build them more typically, then you'll need to revisit the burst. When you line the walls of the shell with stars, there is a lot of room left in the middle for the burst. You can certainly fill it up with granular BP. It's works. It's also sort of a waste in my opinion. Most people transition into coating the BP onto rice hulls or another burst media. This allows for a more efficient use of burst. This is not entirely true, Mumbles. In shells under 5" granulated BP is the correct burst according to Shimizu. It isnt until you approach the 5" range and above that coated BP on filler becomes valuable. Granted we are talking about a 5" here in this thread, but your comment seemed to be a blanket statement which wouldnt be true.
Mumbles Posted July 31, 2015 Posted July 31, 2015 That's true. I was specifically thinking about 5" shells. I've always thought that If someone is going to take the trouble to line their hemis with stars, then a burst on a media is fine. If they're just going to bulk fill with stars, poka style, then mixing in granular BP works well. 3" is about where I make the transition between these two methods. Which Shimizu book does this come up in out of curiousity? I don't think FAST recommends BP until like 8" or larger, and I've never noticed anything about granular burst for anything but insert flowers.
TYRONEEZEKIEL Posted July 31, 2015 Posted July 31, 2015 Its in FAST. There is a chart showing how much BP needed in weight per diameter of shell. Ill find it.
Arthur Posted July 31, 2015 Posted July 31, 2015 With Chinese shells the rules are, if it works cheapen it and cheapen it again. With exhibition shells you look much more carefully at the contents. BP or mill dust is sometimes rolled (in a star roller!) onto crisped rice cereal, sometimes H3, BP or KP is shaken onto damp rice hulls. 1
dynomike1 Posted July 31, 2015 Posted July 31, 2015 I cant really see the difference in Poka and Peonies. In Peonies it's cheaper to use RC with a little flash. What type of sealer are you using? I am still using Xylene.
TYRONEEZEKIEL Posted July 31, 2015 Posted July 31, 2015 Peonies will have a very nice spherical shape to them. Poka will look like a blob. If you arent breaking your shells very hard they may look similar.
braddsn Posted August 8, 2015 Posted August 8, 2015 For what its worth, I have tried granulated in a few 3s and 4s, and coated rice hulls are way more economical and just as powerful. If you use granulated bp for burst you will need more lift also, because the shell will be heavier. I use mcrh in 3s all the way up to 8s.
mikeee Posted August 8, 2015 Posted August 8, 2015 Another option is BP coated granulated cork for the larger shells.
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