daron Posted March 29, 2009 Posted March 29, 2009 hey all just wondering i made my first mortar shot eggs shellsmade my first batch of stars came out good but i couldn't get the shell to go into the air then explode they seemed to explode in the tube then came out like a star-mine still looked good but to low made with a plastic fake chicken egg cut open and filled with small charge and few stars then taped/wrapped tight with a fuse going into lift-cup did i use to much lift and blow the egg to bits b4 it had a chance to leave the tube or did i make egg wrong any ideas would be great
Arthur Posted March 29, 2009 Posted March 29, 2009 Great mine! Read a good shell tutorial and follow it closely. It's really important that the shell case is lifted intact by the lift charge, then fused to break at height. There is every possibility that you used a fast lift powder that smashed the shell in the tube and fired the ignited contents out of the tube. Buy and read a good book on firework making before you make more devices or you will get noticed for all the wrong reasons. Davis, Shimizu,and Lancaster have written good books with reliable information. SOME e-guides may be less good, and some you-tube sources are inaccurate, incomplete ot unsafe.
daron Posted March 29, 2009 Author Posted March 29, 2009 yeah ive been reading up the last 2 yrs and now starting to get into it a bit morei think it was the lift powder beeing 4f its very fastthink ill use less or granulate it more
Seymour Posted March 29, 2009 Posted March 29, 2009 I'd put my money on it being a problem with the egg its self. Perhaps it was not sealed around the fuse, or around the 'equator' where the two halves meet. A good way of doing this, and GREATLY improving the resulting burst is to paste over the shell with several layers of paste and strips of paper. Did you use visco for the timefuse? When this is done several centimetres are wrapped with tape to prevent them igniting in the lift inferno. If this is not done, all the exposed visco will ignite, and the only delay you will get is the time it takes for the visco to burn the with of your shells casing, which is generally not long at all!
daron Posted March 29, 2009 Author Posted March 29, 2009 yeah it was taped up nice and tight and fuse through egg was taped so it didnt preignight starsthe egg is a very hard plastic but i thinki lift was so harsh it smashed everything to bitsshell was 50 grams i used 4 grams lift
Arthur Posted March 29, 2009 Posted March 29, 2009 Cover the egg in paper tape, and make 100% certain that the delay is well sealed. If you used visco as a leader fuse then the casing needs protection from the fire going down to the lift. The side spit of fire from visco could melt or soften the case and start it burning from the top down.
TrueBluePyro Posted March 29, 2009 Posted March 29, 2009 Hay mate this is very simply to fix. What happened to your shell is that the fire from the lift charge some how got inside your shell befor the fuse did, this becuase you most likly didn't seal it properly. Once you close your shell togther make sure you seal it realy good, like it doesnt matter if you go over the top with the hot glue, just make sure you do a proper job around where the 2 hemi's meet and around the fuse.
Mumbles Posted March 29, 2009 Posted March 29, 2009 I think the amount of lift is fine. There is obviously a problem. I couldn't tell if it burst in the gun, or at the point to where you pan up to with the camera. You might want to re-evaluate your building style. Seal the time fuse, both on the inside and out of the plastic casing. Ensure the tape/foil/paper is lays down very well against the fuse to minimize blowthrough and side spit. Make sure the shell is closed tight and sealed. Make sure everything is packed in nice and tight. Looseness can lead to ruptures of the casing. Might want to reinforce everything with some fiber tape or pasted paper or something.
daron Posted March 30, 2009 Author Posted March 30, 2009 thanx guys ill remake some and see what happens:)
FrKoNaLeaSh1010 Posted April 7, 2009 Posted April 7, 2009 I used to make egg shells all the time. they are a simple casing for beginners to work with. as mentioned make sure you seal the fuse o the outside and inside. I used a pva based tacky glue although something else would probably work just as well. Also I used to use fiber reinforced strapping tape and layered the entire shell with it vertically essentially taping the two halves together. If you dont tape them enough them have a tendency to split and turn into a mine. Also one problem I had was when top fusing it my quickmatch was too slow and as it burned down it actually melted the side of the shell as it passed setting off the shell and lift prematurely this is also a possibility of what happened. there used to be a couple good tutorials for easter egg shells. I know there is one on passfire but there used to be another one or two but that was years ago and i cant seem to find them anymore.
daron Posted April 13, 2009 Author Posted April 13, 2009 yeha i had it all taped up tight and no air gaps into egg but you said about top fuse running down the side i recon that might be it cause i used a far bit of 4f in tape as quickmatch hehehe maybe that got it way to hot and melted throughmy lift is 4f so its very fast and makes a hell of a noise on takeoff but i love it:)
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