AirCowPeacock Posted November 20, 2012 Posted November 20, 2012 Hey, I want to make a 3" canister Shell of canister shells. The shells would be the same I make for 1" cakes, 3/4" ID and 1.375" long with 1/4" round TT stars. I should be able to fit 10-12 daughter shells in the main one. How much time between main break and daughter breaks? Are there any other considerations I may be overlooking with a shell of shells? Perhaps I should use slightly oversized stars for my daughter shells? Say 3/8"?
Mumbles Posted November 20, 2012 Posted November 20, 2012 The 1/4" stars sound good to me. For timing it might depend on what you're using as the delay agent. With time fuse I generally don't start my timings below 1/2". With spolettes you can go less than that. For 1 timing of breaks, I'd use between 1/2" and 3/4" depending on how fast the time fuse is. For two timings I'd use a second one 3/8" to 1/2" after the first. If you have some other pattern, let us know and we can see what we can come up with.
AirCowPeacock Posted November 20, 2012 Author Posted November 20, 2012 I want to start in one corner and work my way out to the oposite corner. So I should have 4 or 5 sections. Perhaps 1/32" inches of time fuse added on for every secrion. My time fuse is 3.25 seconds per inch. So that would be 1.675 seconds for a half an inch. If I did 1/32" increments of time fuse starting at half an inch I would end with around 5/8". Now that I think about it having them break at differnet time would make the shell look lopsided because the daughter shells would continue to fly out after the previous section broke. Maybe I should just stick to a syncronous break.
dagabu Posted November 20, 2012 Posted November 20, 2012 Gary Smith just posted a multibreak shell over at PF that used very small stars in very small shells like yours but I believe that he went with 1/8"-3/16" stars and not the larger ones to fill in the break. Also, i will suggest the use of visco wrapped in masking tape (two layers minimum) for the timing since the time fuse will be too problematic. my $.02 -dag
AirCowPeacock Posted November 20, 2012 Author Posted November 20, 2012 I usually use visco wraped in either Al tape or 2 to 4 layers of gummed tape for anything smaller than 1.5", but considering the importance of timing in the daughter shells, I thought time fuse might be more appropriate. However slight variation in fuse time for syncronous breaks could look pretty cool.
Mumbles Posted November 20, 2012 Posted November 20, 2012 I'd go with a synchronous break for your first attempt. It's easy to tell how well it worked. Once you get construction details and bugs taken care of you can get fancy with more confidence. Good luck. For future planning, I'd just like to state I prefer the appearance of an odd number of inserts better if trying to make rings of insert shell breaks. It just makes it appear more round to me.
dagabu Posted November 20, 2012 Posted November 20, 2012 I'd go with a synchronous break for your first attempt. It's easy to tell how well it worked. Once you get construction details and bugs taken care of you can get fancy with more confidence. Good luck. For future planning, I'd just like to state I prefer the appearance of an odd number of inserts better if trying to make rings of insert shell breaks. It just makes it appear more round to me. +1
WonderBoy Posted November 20, 2012 Posted November 20, 2012 I too agree with what mumbles has said, I'd do 1/4" stars, simultaneous timing, and an odd number of inserts when possible. Also, if your timings were only 1/32" apart, your inserts would probably really step on each other. How many of your insert shells will fit in 1 layer, four? Dag, what is your reasoning for taped visco? WB
dagabu Posted November 20, 2012 Posted November 20, 2012 The green Chinese visco I have is very consistent in its burn time and if you wrap masking tape around it a couple times, the sparks are confined allowing you to use it just like time fuse. If cut at a very shallow angle (15° or so) the ends can be primed and with a short timing of 1/2 second, there is just enough of fire blocked visco to hot glue it through a couple stout disks. Its really small too... -dag
AirCowPeacock Posted November 20, 2012 Author Posted November 20, 2012 I'd go with a synchronous break for your first attempt. It's easy to tell how well it worked. Once you get construction details and bugs taken care of you can get fancy with more confidence. Good luck. For future planning, I'd just like to state I prefer the appearance of an odd number of inserts better if trying to make rings of insert shell breaks. It just makes it appear more round to me. Thanks. It is probably the best idea to start simple. It's just when I play it in my head it starts in one corner and moves around. 10 (5 in each ring) will probably be the easiest for me to do, getting 12 (6 in each ring) will be tricky.
psyco_1322 Posted November 21, 2012 Posted November 21, 2012 I don't see you getting that amount of inserts that big into a 3" shell, unless you use more that two layers of inserts. I have used 3/4" ID tubes in 3s before and the most you can get to a layer is 4. If you top fuse them, that's going to be a really tall single break if you do three layers. If you side fuse them, you are going to have the fuses jabbing into each other, and you are going to have nearly no room for a break charge in the shell. You would have to use something nice and spicy to break it. Could you maybe step it up to a 4" shell? That would give you a lot more working room.
AirCowPeacock Posted November 21, 2012 Author Posted November 21, 2012 Unfortunetly I have no 4" morter. 3" is the largest I have. With a quick calulation I have determined that with approximately 0.95" for outside diameter of inserts I can fit 5 in each row. I plan to do two rows of inserts upright literally side fused like a M80. At approximately 1.375" in insert length including rising effects, the inside length will need to be atleast 2.75" which turns to around 3" after spiking and pasting, not including rising effects. The shells will leave me a solid 0.5" for burst, plus a little in between the inserts on the inward facing side. I want to use MCRH dusted with 5% flash for burst. In between the inserts on the outward facing side I want to throw in some well primed stars and a little MCRH as filler. What do you think?
Mumbles Posted November 21, 2012 Posted November 21, 2012 It sounds like you had 1/8" walls Psyco. 1" OD inserts only fit 4 per ring into a 3" shell. 7/8" OD inserts fit a loose 5. You can fit 6 if you enlarge the case slightly. I have my normal 3" former, but for a little bit larger, I've used soda cans before, which are about 2.55 to 2.6" OD, which is about right for 6x 7/8" inserts.
AirCowPeacock Posted November 21, 2012 Author Posted November 21, 2012 I've never tried fusing a shell by its side, are there complications I'm over looking?
psyco_1322 Posted November 21, 2012 Posted November 21, 2012 The tubes I used were actually 1/16" walls. Maybe I'm wrong, maybe you can get 5 smashed in there, I only did 4. I'm not at home right now or I'd go check. If you do side fuse them, you might think about staggering your fuses in the cases, so they don't all hit when you load the case. Be sure you get a picture of the inside of the shell before you load your burst, it will be interesting to see.
AirCowPeacock Posted November 23, 2012 Author Posted November 23, 2012 How about lift and main shell timing? I feel, based on the videos I've seen of small shell of shells, that perhaps I should over lift it a bit and time it a tad short so it bursts just before the apogee. And, should I be conserned about my break being a bit to energetic and damaging my inserts, or will this not be much more of an issue then it would be for regular stars.
WonderBoy Posted November 23, 2012 Posted November 23, 2012 Ahh I forget about you guys not spiking inserts... I've recently been experimenting with side fusing. I like to drill the fuse hole offset at about the 1/3 mark instead if the middle so that you can alternate the insert orientation and have the fuses not run into each other so much. I like to break my insert shells on the way up, especially if there is not a very large burst core (1/2" is kind of small for a 3"), because you often won't get a very large spread anyway. Italian shells are often made like this; check out 21:13 and many others in this video: http://youtu.be/XNNHzYc7Wsw I would like others opinions on this; I have been working with flash boosted cylinder shells recently, using a certain percentage of flash to BP. But there is a lot of variation in this, so I am working to get away from the percentage of burst, to just using a certain weight of flash for each shell size and type. For instance, let's say I'm using about 6% flash booster, a regular 4" color shell, using a slightly larger canulle, might have about 50g of BP burst with 3g of flash. But then I make an insert shell which has much less room for burst, so there is considerably less flash, resulting in a much weaker break. To me it seems like it would make sense to establish your own system of how much flash it takes, using your own materials and methods, to get the breaks you want and apply that to all shells of that size/type, instead of using a percentage of the burst, which will change for every shell.Now I guess this would be more important when using a weaker burst medium, which relies more heavily on the flash booster, but even when using a 'stronger' burst medium, I would think that maintaining the same amount of booster will be most beneficial to break consistency. Dag, I understand how visco can work as a time fuse, I used it many times before I bought time fuse, but in an insert of this size I don't see much of a benefit other than cost. My visco burns at about 3 sec/inch, so taping it to get half a second of timing is going to be a pretty short piece of visco.I'm not saying that it is not effective, this next video uses all visco for timing, but I am just curious why you are suggesting it, when it seems time fuse is more of the accepted practice. http://youtu.be/TWv2Cmz273Y WB
dagabu Posted November 23, 2012 Posted November 23, 2012 Space. I have made many all shells with inserts and timings that short dont worl so well wit tome fuse. Side pinching snd using a slurry works too.
AirCowPeacock Posted November 23, 2012 Author Posted November 23, 2012 (edited) I have visco that burns at 1 in/sec, 2 in/sec and 3 in/sec (by design.) So I would use a half inch of the 1 in/sec, which is not that short at all, about what I use for 1" morters, just with the 2 in/sec fuse. Side pinching? I will prime with BP slurry of course. The burst will be more than a 1/2" cannual in actuality, it will be 0.6" of solid cylinder, plus a little around the edges. More like a 5/8" or 3/4" cannual worth of burst. You make a good point about the flash, indeed you do. I will keep track of the flash used in a shell now, maybe I can come up with some mixed system, like 1% flash dusted MCRH + 'x' grams of extra flash for the given shell size (maybe by volume of shells insides.) Edited November 23, 2012 by AirCowPeacock
AirCowPeacock Posted December 30, 2012 Author Posted December 30, 2012 (edited) I've only been able to fit 8 inserts in my shell, which is very silly. I tried to make my inserts with about 50% larger walls then I normally do, because thats what I calculated would be perfect fit. However, in reality I made them slightly larger than I wanted, only so slightly, about 1/64 or so to large, and now I fit a loose 4. I should have made them 7/8" as normal, and pasted on layers from there as needed, constantly checking if they fit. Now I have two extra shells with too short a timing and slightly to wide an O.D. to shoot as a morter. I may use them as an ascending flowers effect on the shell though. Man I have alot of work cut out for me before NYE. Edited December 30, 2012 by AirCowPeacock
Mumbles Posted December 30, 2012 Posted December 30, 2012 If it's not too late, you might want to try rolling a larger casing. I mentioned before that I use soda cans occasionally for a larger ID. They're about 2.55 or 2.6". You can also wrap a few turns of manilla file folder paper or cereal box around the former before rolling the casing to enlarge it slightly. Everyone has this problem at some point. 3" shells have quite a bit of working room even after spiking and pasting. Making the casing larger really isn't a problem. I usually size the inserts approximately, and shim them into rings with chipboard. It's way easier than trying to perfectly get the OD just right. Having them snug makes it easier when you're packing them in with sawdust/polverone/clay.
AirCowPeacock Posted December 30, 2012 Author Posted December 30, 2012 It is too late, I'm just about to spike and paste the shell. I wraped some duct tape around the former til it was ~2.57" then I could force all the inserts in creating a pentagonal(?) shell. But I thought that might not be the greatest way to go, so I went with the original casing I made. For my 'spicy' burst I used an essentially random mixture of MCRH, 2Fa, 4Fa, slow flash, thunder #3, and corse benzolift. It was about 50g of burst all together.
Mumbles Posted December 30, 2012 Posted December 30, 2012 When you pack in the inserts the shell rounds out. When I make 5 and 9 timed spider shells, the casing starts out almost square.
AirCowPeacock Posted December 30, 2012 Author Posted December 30, 2012 Shoot, maybe I should have used that larger casing, Too late now. I've got some photos, but...they didn't turn up exactly where I thought they would when I uploaded them... The shell unspiked is 4.5" long.
AirCowPeacock Posted January 2, 2013 Author Posted January 2, 2013 (edited) The shell worked great, but the rising firefly stars appeared to suffer from the cold that night. I had one stragler though, I must have mixed up the fuses, because I cut fused all my shells for newyears all at once, I must have grabed one of the 0.75 sec fuse for a salute and stuck it in one of my insert casings (the rest were 0.5 sec.) The dragon eggs refused to work at all at -25ºC. I also had problems with the torch/lighter. I ended up having to go back inside, warm them up, put the torch into a pair of mittens, and strap the lighter too my thigh. Yeah,... I wont be able to get a video up til the end of the week, I'm out of town and have no computer, just my phone. Edited January 2, 2013 by AirCowPeacock
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