Arthur Posted July 22, 2014 Posted July 22, 2014 When making a pattern shell (heart, face etc) does the star pattern sit on an equatorial plane or on the surface of the hemi?
VikingPyrotechnics Posted July 22, 2014 Posted July 22, 2014 (edited) You fill both hemis with your burst charge. On one of the hemis you lay your pattern that you want direct on the burst charge and put the two hemis together. That´s all And sorry for my bad english ......... Greets from Germany Edited July 22, 2014 by VikingPyrotechnics
Zumber Posted July 22, 2014 Posted July 22, 2014 One of my friend send me this image of cardboard face (thanks to him first)Fill the hemispheres with bp burst then put the stars on equator see the image attatched then put that pre cutted face shaped cardboard in hemisphere.This cardboard will hold position of star fixed.Next arrange star in cardboard (for smile) then for eyes paste stars with glue on two strips wich will look like eyes (see cardboard image).you can aslo glue stars at equator. 1
Fourthsaxon Posted July 22, 2014 Posted July 22, 2014 More ways are leading to Rome . . . 1)Like above. glue the stars on a pre-cut thin cardboard disk. This way you can make good 2D shapes. 2)Make a tube(sleeve) out of good gampi tissue. Stars must fit good in them, no much space sitting around. If you have acces to good quality tissue you can make a 40cm tube on a rod. Using little bit varnish the tissue will stick together.When the tube is completed, gently lower your stars in them. You can now create any desired shape you want by bending the filled tissue tube. Once shaped use again spray varnish to hold the tissue in shape. When using method 1. Think about using a tissue paper for sepperating burst and stars. PS: I'm not a stock holder on Kleenex.
Mumbles Posted July 22, 2014 Posted July 22, 2014 I've seen a few shell autopsies where a decent portion of each hemi was filled with a filler. Sawdust, rice hulls, cotton seed, clay, whatever cheap filler you have available is used to fill both hemi to within about an inch of the equator. Then this is sealed in with paper or cardboard, or whatever cheap material you have, while also allowing for a passfire tube from the fuse. Then the remaining space is filled with stars in the pattern and real burst charge. This is said to save on materials and not really affect the performance much. Basically all you need to do is burst the pattern out radially. Not having burst perpendicular to the pattern of stars really shouldn't do much of anything. 1
nater Posted July 22, 2014 Posted July 22, 2014 Does anyone make patterns accounting for the difference in speed from stars ejected from the center of the hemi to the perimeter?
Arthur Posted July 24, 2014 Author Posted July 24, 2014 I once thought of a selection of components for a multibreak each containing one character, so that you could pick two initials a heart and then two more initials, and assemble them for the event.
pyroman2498 Posted July 24, 2014 Posted July 24, 2014 Skylighter posted a article on this a while ago http://www.skylighter.com/fireworks/how-to-make/star-pattern-shell.asp
MrB Posted July 24, 2014 Posted July 24, 2014 I've found that the distance to center doesn't really matter much when doing patterns like these. Which is encouraging since i've been wanting to make "box" and "prism" kind of pattern for a while. But 3D patterns aren't that easy to build. When i say box, i mean outlines, edges. I'm not sure it would please any audience, but it speaks to me as a builder.B!
modestmortal Posted July 24, 2014 Posted July 24, 2014 That's very interesting Mr. B. How would you go about building a 3D pattern? Possibly gluing the stars together with spacers between them, forming half of a "box" for each hemisphere then matching the stars when closing?
Arthur Posted July 24, 2014 Author Posted July 24, 2014 I've tried a cube before, I used a frame made from gummed Kraft tape and stuck the stars into it. Didn't work well The big issue seems to be the NEC for commercial units or the simple quantity of BP consumed in a home made item.
MrB Posted July 24, 2014 Posted July 24, 2014 Since i haven't actually managed to do one, only read about it, it pretty much goes like this: Make your shell casing into a enclosed ball. Cut away one end of it to make a hole in to it through which to build the entire shell.Build it in layers. Start with breakcharge to make a flat working surface, and build your design from there. Tissue paper "rings" help with spacing and alignment, but you have to make sure there is break in them.Compact everything carefully as you build. Once the hemi is filled, your entire design should be in place. Take the "lid" and if it's small enough, just add a handful of break on top of the rest in the shell, and "make it fit" so you get a solid shell. If your "lid" is larger, fill the slight cavity, keep it in place with some tissue paper, and put the thing together. It's supposed to work, the issue seams to be compacting everything equally without distorting the pattern, and managing to get a symmetrical break. I'll let you know how it goes, if i manage to build something that i feel reasonably confident will work out, and actually shoot. So far i've always ended with tearing it apart, and at the end of the day, it's just become half a hemi, or a ring shell anyway, due to lack of time and not wanting to leave stuff around...B!
marks265 Posted July 24, 2014 Posted July 24, 2014 If you ever try a cube shell make sure that you use a different color for one of the three dimensions otherwise it might look similar to this Mark
schroedinger Posted July 25, 2014 Posted July 25, 2014 Did anyone ever think about building a cubic shell, and nest this inside a paper hemi, together with bp coated ricehulls. Build the paper with just one or two layers of pasting (if not enough to fit inside the mortar, cut the pasting at the equator, untill the last two pastings). Now you fire this shell and break the hemi apart after about 1 second. Due to the use of only two pastings the paper it should rip appart, without damaging the now free cubic shell, which will be broken at apogee. Also i could think about a design, where a canister shell is loaded with the cubic shell. The cannister being made of a quite strong tube (about 10 turnings of kraft). Now you insert a couple gramms of bp into this shell, on top you insert a cardboard disc and after this the cubic shell. On the bottom side the cannister is pleated like normal, but on top it just gets enclosed with some tissue paper wadding for fireproofing and 1 layer of heavy kraft. This way the cubic shell would be ejected like from a mine, and fired maybe 1 second after the ejection.
gun410 Posted August 2, 2014 Posted August 2, 2014 Skylighter posted a article on this a while ago http://www.skylighter.com/fireworks/how-to-make/star-pattern-shell.aspThanks that helps I always thought It was hard to make them but it easy!
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