gandelff

seymour i think you may of hit the nail on the head there fella, it might be my burst charge is insufficent rather than my booster,i have sone grass seeds, coated in bp that might be more suitable, as i have never really paid that much attention to the filling( burst charge ) i have always occupied my thoughts to the booster thinking that this is the break charge, i will do some research and experimentation and get back to you but i definatly think that this could be the reason for not getting the shell to break clean in halve, oh before i disappear,

the break in my shells get ignited from the fuse running from the end of the rocket motor fuel , through the bulkhead of clay and into the bottom of the shell, obviously its very hot and ignites the bottom of the break charge almost as soon as it enters the shell, should i differ this arrangement to quick match instead so i can try to light the top part of the break charge too or is it all happening so fast that it wont make any differtance

I use a 3 gram flash/break charge made up of 50/50 mix kno3 and german dark aluminium sometimes,

and others i use a 70 /30 whistle mix potassium perchlorate and sodium benzonate
prepared by hand grinding both chems seperate in a mortar and pestle then diapering them together, and then make a 70/30 mix of whistle mix with ball milled bp, though i dont mix it if that makes sense,

i prepare my break charge by placing the 3g of whistle in a small heap in the centre of a single piece of tissue paper(andrex am posh) and add just under a gram of bp on top of this and wrap the mix up and hole it and place the wrap ontop of the fuse. now should i be diapering the bp in with the whistle mix or is my comp not fast enough for a break charge, i like using this mix as it gives tremendous heat as well as fast, maybe if what your saying is that it isnt fast enough

as for confinement wow 10 sheets thats alot, i get bored after 2, though i do use natural twine and when dry it is solid, i will make another tonight and stick with the paper strip method and add the extra layers, before i do should i increase the size of the break charge or change it, the filling will be coated sugar puffs and the stars will be 1/2" chrysantyhm 8's so not too much heat is required to get them firing, just this breaking of the shell that i have to focus on at the mo

the effect/spread of stars i really want to achieve is a nice symmetrical ring,i use the hard cardboard hemisphere,i also use the hemisphere pots also made out of cardboard, i also use toilet roll tubes, etc., and then i string them and 3 strip paste them really well and leave to dry,
when they ignite in the sky there not coming out in the circle formation that there in the shell in, upon retrieval of the spent shell and rocket(sometimes a tough job on a wet and muddy farmers field) the shell header/payload casing isn't clean blown into the original 2 halves, more blown apart like a fragmentation grenade, so thus i know that my burst charge is strong enough to break the casing and fling the stars out its trying to find the art/skill in making them make come out to make a ring of stars if that makes more sense, i know if i for example stacked stars ontop of each other in a long tube(1/2" x 4") and had a lift charge at the fused based and taped and strung and 3 stripped etc the chances of all the stars getting fired out from the casing from the end of the tube is high, the effect i imagine will be similar to a shot gun spread,but with my round shells they also come out in this manner, i want to wooo the spectators /family members with these nice circles/lines etc as described by seymur

sorry for the delay , am mad busy at work and never stop, i do prime all my stars, even tiger tail which ignite at the mear mention of flame, some of the chlorate comps i use a thermite coat but it depends on how hard they are to ignite, anyway back to my original post,i think i am getting the confinment factor ok, as the stars are getting thrown out from the rupture blast and they are igniting, its just not clean at the half sphere where ive taped, i was wondering when making my pots and closing the 2 halves together and taping or glueing(depending on the pot in question) wether i should prick small holes in the joining tape( knid of a serrated line) then do the confinement 3 strip paste, so when the break charge ignites all the coated filling and stars and starts to expand it finds this as a sort of weak point and ruptures more cleanly? what do you reckon? worth a try, or is there a more suitable method such as not over sealing the pots?

wow,amazing answers,i think i asked more than one question and will `upload an image later on to show you what and where my casings are rupturing, anyway it is the symmetry of the stars that i am at the stage off now, i use loads of differant types, the greens in question were

metallic green hardt green star #1
Barium nitrate 39
Barium chlorate 27
Potassium chlorate 16
Red gum 13
Dextrin 5,

if i test them on a flat surface they take some going to get started,though once fired they cook nice and bright, but do find the heat has to be long and intense which leads back to the confinement theory as posted by seymour,i will have to leave it there as due in work in a mo but will add more and the photo this evening and hopefully explain it better then.thanks guys