AldoSPyro Posted August 13, 2014 Posted August 13, 2014 I'm currently thinking of building a 3" traditional can shell using information from pyrotechnica IX (http://www.pyrobin.com/files/pyrotechnica%20ix.pdf). I want to use D-1 glitter but i don't have much experience making rolled stars, would it be possible to make a decent looking break using pumped D-1 glitter? Should i fill the shell (around the canulle) with 3/8" pumped D-1 like i would with rolled stars, or should i line the walls of the shell with 1/2" pumped D-1 comets? I'm new to canister shell making and any advice would be helpful !
Jordan Posted August 13, 2014 Posted August 13, 2014 (edited) When using pumped stars in a cannister shell it is generally not recommended to stuff them in around the Cannule. This method works best for cut stars. You can use the "brick wall" style of setting stars, this is done by putting down a ring of stars on the bottom of the shell and filling the empty spaces on the OUTSIDE with rough pulverone. This method is repeated with the center of the star on the next layer directly above the gap in the previous one. You do not need a Cannule for this method and burst can be poured in and leveled with rough pulverone. Ned gorski has quite a few 3" construction videos detailing this method. 1/2 inch comets might be a little big for a 3" shell. They are harder to align and depending on your former O.D. May leave large gaps in between. 3/8 is about the largest you want to go with tailed stars in a shell that small. Good luck Edited August 13, 2014 by Jordan
schroedinger Posted August 13, 2014 Posted August 13, 2014 If you want to use D1 you should really go down to 6-8 mm (with prime) stars, or these are very likely to make it down to the ground. Yes D 1 works beautifull in pumped stars, but if your hands allow you to grab inside a 3" shell then stack 'em in a wall brick like manner and shim them in place. This is much faster and easier then using sawdust or other between the stars and walls, but both work. If you just got the 3/8 pump. Use 'em with an extra gram of lift and mill the whole comp without the aluminium instead of just screen mixing. Then screen in the aluminium.
TYRONEEZEKIEL Posted August 13, 2014 Posted August 13, 2014 When using pumped stars in a cannister shell it is generally not recommended to stuff them in around the Cannule. This method works best for cut stars. You can use the "brick wall" style of setting stars,Jordan, I do not know where you heard this. Unless you mean just sloppily dumping them in there,it isn't true. The point of using pumped stars is allowing consistent sizing of stars so that they stack and stuff themselves in tight 'brick wall' pattern that wont shake out. I have made stars so large in a shell so that the gap left was just the cannule. Aldo, great job on following Fulcanelli's article! You can use rolled stars perfectly in a can shell, you just have to put them in layer by layer, not pour them in haphazardly. with each layer you have to pack in polverone so that each layer begins on a perfectly flat surface. To avoid that tedious work, use cut or pumped stars. As far as the star sizing goes, that is only subjective to your taste and how you implement the shell. I would personally try the 3/8" stars first and check their burn time. That seems pretty large for a small shell. However if the shell is an insert for a larger shell, I would use the 1/2" stars. Again it is all relative to your taste. Feel free to PM me if you need anything!
Shadowcat1969 Posted August 13, 2014 Posted August 13, 2014 (edited) Here are some links to cylinder shell building tutorials by Paul Moulder. You might have to poke around a bit, but he does have one about loading pumped stars into a cylinder shell, and also how to fill and close once the stars are loaded. http://www.amateurpyro.com/forums/topic/9792-cylinder-shell-building-videos/ Edited August 13, 2014 by Shadowcat1969
Mumbles Posted August 13, 2014 Posted August 13, 2014 I just wanted to preface this by saying that you can get away with a lot of short cuts and kind of sloppy techniques in smaller shells like this. If you want to stick to traditional, you can forget about rolled stars. Cut stars or pumped stars are best. They lock together better. I imagine you can easily just fill in around the cannula with 3/8" pumped stars, and fill in all the spaces with polverone. When you have the shell filled, but before closing it up, you should be able to squeeze the side of the shell and feel just a solid mass. It shouldn't give at all. If you choose to stack comets around the wall of the shell, even if you do use shims, you still should fill in the spaces between the wall and the comet with sawdust or polverone or something. You want to avoid all soft spots and air pockets. Depending on the cavity left in the middle after the comets and locked in, there are a few options. If the cavity is around the size of a normal cannula, you can just fill it with granular BP. If it's significantly bigger (like 2x as large as normal or bigger), you can put a normal cannula in and fill in the remainder with polverone. Alternatively, you can use a blend of 50:50 BP:Polverone and just fill the whole thing in. I think you'd be fine with 3/8" D1 pumped stars in a 3" shell. If you choose to use 1/2" pumped comets, you might want to go with something a little faster like C6 or spider stars or something. You can also always give cutting stars a shot as well.
Arthur Posted August 13, 2014 Posted August 13, 2014 Remember that while building and pasting and binding a cylinder shell the wall of stars is all that holds it rigid, it works with even lengths of pimped stars but doesn't work with round stars. In a round shell round stars pack easily and well and as the strength is the hemi it's easy to paste them.
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