Pretty green flame Posted September 17, 2006 Posted September 17, 2006 The exposed part of the shell leader looks far to short to be safe. Other than that it should be fine.
moonshot Posted September 18, 2006 Posted September 18, 2006 Mumbles, He lit the shell, put it in the barrel of an air cannon, and then fired it into the air pneumatically...no lift charge and very dangerous. Moonshot: Looking at your pictures, I can see the top disc where your timefuse enters the shell; that's not a good thing. Pasting the shell involves covering the entire thing with a few layers of pasted paper which seals it from the lift gasses. It's usually done after stringing as well. I think you'll find your shells blowing in the mortar because of an improper seal around the edges. Be careful. Frank, now I understand what you are saying about pasting the entire shell. I've been looking at the shell construction guys are doing on the UK Rocketry Forum and realise my shells are incomplete as far as pasting, lift charge and quickmatch leader is concerned. Those were the first ones I ever built and I was going off a tutorial that didn't include the final steps. After seeing some of the larger shells the more experieced pyrotechs are building I really feel like a newbie amateur. Someday I'll get the experience to step up to the larger shell construction. Until then I will work on perfecting my smaller shells so I can apply correct building techniques to larger shells. Thanks for the advise.
hashashan Posted September 18, 2006 Posted September 18, 2006 Yo guys, i had a weired idea and before i blowing my arms off i would like to consult it anyone tryed making a whistling spoulette?
Mardec Posted September 18, 2006 Posted September 18, 2006 That is not such a bad idea Would be nice to see a shell whisteling to break altitude.Only problem is that whistle will burn to fast I think. But I don't have experience with making spoiletes.I would like to use them but I don't have an idea how. Anyone knows a nice tutorial? I thought there was one on yuki's site but I can't find that site anymore.. Timefuse is costly
Rocket007 Posted September 19, 2006 Posted September 19, 2006 here the video of my 2" shell with ganit stras. the spoliete was only 1,5s . i will make now longer burnig 3s spoliete. the shell was lifted with 10 g bp for a 95g shellburst bp video Lp, RokBTV here can you look for spoiletesLINK1
Silverturk Posted September 20, 2006 Posted September 20, 2006 Hope you mean 10 gram and not 0.1 gram. Nice shell btw
Cherbanov Posted September 29, 2006 Posted September 29, 2006 I have make may self a 45mm shell that is quite havy 118gram and i made a dummy shell and loaded 25grams of 4h ball mill and granulated BP as a lift charge but the dam dummy just went about 15 meter in the air and then went down. wath did i wrong, is it to little powder? the sound was like flofff not bomm, the pipe is like 47mm ID.sorry for the bad english you now swedish gays arent that god at english speling. the pipe ore mortar is about 50cm long
Silverturk Posted September 29, 2006 Posted September 29, 2006 If your mortar is 47 mm ID and your shell is 45 mm, it has a very snug fittning in the mortar. I would guess that your BP is to bad. BTW I'm also swedish! Så snacka inte skit om vårat fina land!!
joe609 Posted September 29, 2006 Posted September 29, 2006 I disagree completely 2mm especially if your BP isnt that good is quite alot of space for gas to escape I reccomend wrapping the shell with a few layers of tape to get it snug, make it so you have to push the shell down the tube, if it falls by itself then its to loose.
Mumbles Posted September 29, 2006 Posted September 29, 2006 I disagree completely 2mm especially if your BP isnt that good is quite alot of space for gas to escape I reccomend wrapping the shell with a few layers of tape to get it snug, make it so you have to push the shell down the tube, if it falls by itself then its to loose. I don't know what the hell kind of shells you're building, but you most certainly do want the shell to fall by itself. No sane shell builder should ever have to push their shells down. The chance of flower pot are much higher, and to properly load it, one must place parts of their body over the mortar, which is a big NO-NO. 1mm on each side isn't anything to be worried about. I think the problem is in your BP. If your ballmill isn't designed to work at maximum efficiency, 4 hours won't be enough. Also, what size are the granules of lift you're using? Charcoal may also be an issue.
Rocket007 Posted September 29, 2006 Posted September 29, 2006 i make now a BP (wil send wideo tomorrow) i first grind C (black alder) and KNO3 in a coffee grinder (severally of course).thej i put everything in my ball mill for about 1h and i bocem out my best BP. i granuated it and then i burn it it bur with a lightning. trial my manner of work LP, Rok from Slovenia
joe609 Posted September 29, 2006 Posted September 29, 2006 Fair enough but ive always had good results with having a snug fit and having to push the shell down (not hard) it would gently slide down with some encouragement, but il try it with more of a gap and see the difference.
artificier Posted September 30, 2006 Posted September 30, 2006 i will firing a 3" spherical shell last week http://img201.imageshack.us/img201/8021/activit2006050jv5.jpg i will put : red , green , blue and kamuro stars in it¸i use around 75g of granulated Bp and 1 tsp of kno3/mg powderand i use commercial grade Bp lift charge. you see the smoke of one of my firework before this explosionits my another 3" spherical shell with the same breaking charge and liftbut i use kamuro stars. http://img222.imageshack.us/img222/3285/activit2006071dg6.jpg i will make a nice show for my family lol
Mardec Posted September 30, 2006 Posted September 30, 2006 Is that first shell yours ? That is the most beautifull shell I have ever seen (3") Anyway I have a serieus question. I just fired a 2" dummy 11 gram very course BP where needed to shoot it to good height.It was a 94gram can. Now how much of this bp would I need to fire a 3" ball? Weight unknown because I still have to make it One I make the bp less course (some particless are over 5mm I will probably need less. And does a shell fire higher if it is lighter?And If it is a snugger fit does it fire higher? Sorry fot the many questions, but I think I am close to good lift
artificier Posted September 30, 2006 Posted September 30, 2006 normally i use around 1 ½ tsp for 2" shell and 2 ½ tsp for 3"shell BUT its not the same quality, i used commercial lift and NOT homemade lift , homemade lift need more powder to lift the shell.and use coarse powder, because fine powder burn more slowly.
leosedf Posted September 30, 2006 Posted September 30, 2006 I make my lift with Balsa Charcoal BP. Very powerfull stuff!
Pyrohawk Posted September 30, 2006 Posted September 30, 2006 Mardec: My 3" ball shells usually weigh about 130g.....but I use coated Rice Crispies which don't weigh much. Just go with a ratio... You used a 1:9 ratio to fire the dummy so use 1:9 to fire the shell.So for instance if your shell weighs 130g use 15g to fire it. It works best to do it by weight until your shells are consitant in weight than you can just go by rule of thumb. Mine always weigh 130g so I always use 12g.... Artificier: Those are some beautiful shells. I am interested as to what stars you used in that first one?
pa_pyro Posted October 1, 2006 Posted October 1, 2006 A little off topic, but here's one of my 1" cup shells with charcoal streamers. http://www.zshare.net/video/000_0001-mov-s3t.html (nice shells artificier I would also be interested in the first shells comp)
Rocket007 Posted October 1, 2006 Posted October 1, 2006 LP Here is my new project, my 3 1/2" shell with white TT stras. the burst is granuated BP. here are some pictures. http://www3.shrani.si/o.php?dscf0091970428.jpghttp://www3.shrani.si/o.php?dscf0093970429.jpghttp://www3.shrani.si/o.php?dscf0092970430.jpghttp://www3.shrani.si/o.php?dscf0089970431.jpg now without pasting it weight about 440g. I will let it fly not later then saturdey. thw lift will be granulated BP about 13/100 ratio. ti has a 3s spolett . It is possible that a weight tt star burns orange-yellow (If only the wals of the star are dryed) ????? BTW(Pa-pyro a nice 1" shell, maybe a bit longer time fuse or spolett and no zoom pliz) ROK
artificier Posted October 1, 2006 Posted October 1, 2006 i used commecrcial product to make my shell and i just mix green,blue,red and kamuro stars.The effect look like a peony but my cam exposure make a buzz effect like the first pic.
Mardec Posted October 1, 2006 Posted October 1, 2006 So you buy shells and destroy them and make new shells out of them ? Where is the fun?... Anyway, I thought it was some form of go-getters.. They don't go straight, but change directions because of their thrust. But they are pressed into tubes.
artificier Posted October 1, 2006 Posted October 1, 2006 noo one of my friend give me the powder and stars !
pa_pyro Posted October 1, 2006 Posted October 1, 2006 Did your friend make the stars himself? Maybe you can get him to join the forum. Too bad the star effect was from the camera, that was an awesome effect.
Mardec Posted October 2, 2006 Posted October 2, 2006 Try to make go getters They have the same effect , but they go everywhere.. Maybe if the break is powerfull enough they will give the same effect as that picture because of the power of the thrust from the stars will be smaller then the kinetic energie of the burst. So they will go more of less straight. On cannonfuse there is a tutorial about making go-getters.
Pretty green flame Posted October 3, 2006 Posted October 3, 2006 Good evening Well my problem is as follows: I want to achieve some high altitude breaks from 3" and 4" round shells. I have been talking to karlfoxman from UKR and he has reccomended the use of spiked lift charge canister and tight fitting pistons, i am certain that this would works but i'm looking for something a little less time consuming. Should i alter the BP grain size (right now it's -10mesh and stays on a 20 mesh screen) to something finer like -20mesh. Make the mortar longer, if so by how much Make shells more tight fitting by increasing the shell diameter? Thanks PS: If anyone knows. Do the chinese use break booster in their 3" and 4" shells (Flash, whistle)
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