Aerial Shells

[viziers]

Yes it is only a cardboard tube, albeit a stout one at that. The walls are about .5'' thick. Here's the other piece of tube like it that I have -

Tube

Tube End

 

You can see that the end is all gnarly. That's only because I'm not too graceful with a reciprocating saw!

Well it deffinately is sturdy enough being its a 1/2" wall tube just do everything you can to keep it dry and away from moisture and youll be fine.

[d4j0n]

So I'm having trouble getting ignition on my first non organic star.

 

Shimizu Golden Wave No.1

37 potassium nitrate

9 antimony trisulfide

47 Aluminum flake

1 boric acid

6 dextrin

 

I cut and primed them like crazy with slow bp and they just don't wanna light. Any suggestions?

[TheSidewinder]

DB,

 

Did you coat that tube outside *and* inside with epoxy? If not, make sure to get the inside. If you do, that tube will last a LOT longer.

 

M

[Mumbles]

d4jon, the problem lies within your prime. That star has a very high metal content. I would suggest using a hotter prime. You will want something with metal in it. The pfp database should have a suitable prime.

[_DB_]

I only used epoxy to attach the mortar to the wooden base. I did manage to slightly coat the inside with spray paint by just spraying down in it though.

[ravaz]

So I'm having trouble getting ignition on my first non organic star.

 

Shimizu Golden Wave No.1

37 potassium nitrate

9 antimony trisulfide

47 Aluminum flake

1 boric acid

6 dextrin

 

I cut and primed them like crazy with slow bp and they just don't wanna light. Any suggestions?

Like Mumbles says, your prime is probably not hot enough to ignite that comp. With rolled stars, what I'd probably do is use a 2 or 3 step prime for that star to guarantee ignition.

 

-Star-

 

First Prime - 75% Star comp / 25% BP

 

Second Prime - 50% Star comp / 50% BP

 

Third Prime - 75% BP / 25% Star Comp

 

Then a thin layer of hot BP over that. Something like that. I do something like this when priming a high aluminum comp. You can always add Silicon, Flake Alum, MG/AL, or fine Fe/Ti to a green mix to make it a hotter prime and cut down the steps.

 

I did this with some 9/16" flitter stars that contained 50% aluminum in the comp, and they work perfectly fine with no noticable delay with the star igniting. Good luck.

[justanotherpyro]

A good way for stars in general is 10% flash grade Al in some meal. Ravaz's way is very good though. The exception I use is instead of star comp is 3 steps with green mixed BP instead of star comp. Both work well I imagine.

[_DB_]

Now that I have my mortar made and everything I'm having problems with launching dummy shells to their appropriate height. I think my my mortar's ID is slightly too large. To fix that I plan on pasting a thin strip of Kraft around the seam of a completed shell. Would this badly affect the breaking of the shell? I figure with better-fitting shells, my problems will be solved. My lift is not the problem I don't think. My avatar is a still of 2 grams burning.

 

EDIT: I think instead of pasting a strip of kraft I'm going to use some sort of tape instead. Probably electrical.

[aquaman]

How much space is there between the shell and the tube on both sides? Some space is good as it will push the shell rather than a punch if the shell was too tight.

 

If there is a little space then it is either your lift or not enough lift, possibly both.

[_DB_]

There is about half a centimeter of space on each side. For lift I used 1/10 of the dummy shell's weight. My lift seems very good. It burns instantly with a poof and makes an airborne fireball. I think compression is the issue though. I test launched a water bottle that scrapes the sides of the mortar when it slides down inside. I used the 1/10 rule for it and it launched quiet nicely. I tried it out and to make the shell fit nicely you have to use quite a bit of electrical tape.

Shell 1

Shell 2

I'm afraid using that much tape along the seam might make it too strong. I don't know though.

[justanotherpyro]

There is about half a centimeter of space on each side. For lift I used 1/10 of the dummy shell's weight. My lift seems very good. It burns instantly with a poof and makes an airborne fireball. I think compression is the issue though. I test launched a water bottle that scrapes the sides of the mortar when it slides down inside. I used the 1/10 rule for it and it launched quiet nicely. I tried it out and to make the shell fit nicely you have to use quite a bit of electrical tape.

Shell 1

Shell 2

I'm afraid using that much tape along the seam might make it too strong. I don't know though.

There can't really be too much. Even pasting is a good thing, so try evenly pasting it to a size that will fit your mortar nicely. This will make your launches better, and give a better break.

[_DB_]

I don't really want to paste them since I have terrible pasting skills. I'm going to test launch the taped shell tomorrow with 1/10 the weight in lift. I was thinking that if you made the seam really strong you might get bow-tie breaks.

[justanotherpyro]

Then paste vertically with tape untill it is a good fit. Pasting skills get better with practice, so practice.

[d4j0n]

Yea the prime on the golden wave just needed a bit of metal, time to actually FULLY dry , or both. They actually weren't that hard to light cause I used dark aluminum.

 

Something like this is too low, huh? Or can I not expect it to go any higher? If theres no hope I guess I gotta make the stars smaller.

 

-1" paper cup set shell, snug fit. Lifted with 6-7g of granulated mesquite charcoal lift.

-Granulated bp burst boosted with 2 pinches of loose flash.

-Stars: <1/4" newspaper based chrysanthemum of mystery & larger but pretty much non-visible shimizu golden wave #1 (aluminum is too fine, just looks like white burst sparks)

 

http://d4j0n.freepgs.com/pyro/video/mini%2...tery%20divx.avi (divx encoded)

 

Sorry, vid cuts off early. I was busy ducking away behind my car in case any stars decided to fly in my direction and smack me in the face.

[bubbelpower]

How high did it go?

 

My 1" shells go about 100ft. into the air, like the commersial ones.

[viziers]

Ok i have a potential problem here, I had lit my first live 3" shell that weighed 114.3 grams and had used 18 grams of lift.

The fuse for the shell is from pyrocreations and was cut 3" long and was timed, set and hot glued into the shell and yes i tested it to make sure it would burn through a test half of a shell.

well the problem was the shell lifted perfectly butdid not go offin the air it came down to the ground and when i found it this morning i noticed that one of two things happened

 

1. the amount of lift i used might have blew the fuse to pieces causing it to not light the fuse and go off cause i did not see any spark trails following the shell upwards.

 

2. well i dont know what the second reason would be but i do know that the fuse was sitting well into the lift charge.

 

 

Anyone have any speculations or ideas why it did not go off??

[TheSidewinder]

Hmm, if you've sprayed the inside with paint, I don't think my advice will work. But you can try it if you want.

 

What I've done is take solvent-based Shellac or Varnish, thin it 50% with alcohol, dip the tubes completely in it, then hang and let dry. I have some 2-year old cardboard mortars that I treated this way and they still look brand new. No seperation of the inside at all, and they've each had dozens of shells shot from them by the Guild (I donated them to the club as a launch rack).

 

M

[d4j0n]

How high did it go?

 

My 1" shells go about 100ft. into the air, like the commersial ones.

I'm guessing about 3 stories. Do your shells fit snug in the mortar? Mine aren't tight, but they don't fall in by themselves and I gotta push em all the way to the bottom.

[bubbelpower]

My shells are fitting perfect. There are no free space at all, but they slide down by them selves. THAT is a perfect fit for 1" shells

[justanotherpyro]

Ok i have a potential problem here, I had lit my first live 3" shell that weighed 114.3 grams and had used 18 grams of lift.

The fuse for the shell is from pyrocreations and was cut 3" long and was timed, set and hot glued into the shell and yes i tested it to make sure it would burn through a test half of a shell.

well the problem was the shell lifted perfectly butdid not go offin the air it came down to the ground and when i found it this morning i noticed that one of two things happened

 

1. the amount of lift i used might have blew the fuse to pieces causing it to not light the fuse and go off cause i did not see any spark trails following the shell upwards.

 

2. well i dont know what the second reason would be but i do know that the fuse was sitting well into the lift charge.

 

 

Anyone have any speculations or ideas why it did not go off??

First off, did you use visco fuse? For my 3" shells I use 3/4" length of visco fuse for a 4 second delay, not a 3" length! If the fuse you have burns that fast then it may not be able to withstand the lift charge like you said.

 

If the fuse is getting ripped to shreds, then apply some wood glue, tape, or at least something to strengthen the outside of the fuse. On top of that, prime the end of the fuse. Both ends if you want an absolute guarantee on ignition. A little rub of BP slurry does great.

 

A possible theory is that the timing was way to long and the fuse outside of the shell may have still been burning when it crashed to the ground and got snuffed out, or broken off. Then again I wasn't there so I don't know.

[Frozentech]

Ok i have a potential problem here, I had lit my first live 3" shell that weighed 114.3 grams and had used 18 grams of lift.

The fuse for the shell is from pyrocreations and was cut 3" long and was timed, set and hot glued into the shell and yes i tested it to make sure it would burn through a test half of a shell.

well the problem was the shell lifted perfectly butdid not go offin the air it came down to the ground and when i found it this morning i noticed that one of two things happened

 

1. the amount of lift i used might have blew the fuse to pieces causing it to not light the fuse and go off cause i did not see any spark trails following the shell upwards.

 

2. well i dont know what the second reason would be but i do know that the fuse was sitting well into the lift charge.

 

 

Anyone have any speculations or ideas why it did not go off??

What kind of fuse did you use for timing ?

 

If you are using 1/4" time fuse, 3" is way too long. You want about 1 1/4" between cross match. I don't use visco fuse for shell timing, but friends who do, have pointed out that the priming of the take-fire end is critical. Also, you would again be using about 3 times too much fuse. Chances are, whichever type fuse you used, with that long of a delay, it hit the ground and the impact broke the powder train.

 

You didn't say what condition the fuse was in when you found it. Had it taken fire and partially burnt ? Or as implied by not seeing any spark trail, did it just not light ? If that is the case.

 

18 grams is a good amount of lift charge for most 3" shells, so it shouldn't be that.

[viziers]

Ok i have a potential problem here, I had lit my first live 3" shell that weighed 114.3 grams and had used 18 grams of lift.

The fuse for the shell is from pyrocreations and was cut 3" long and was timed, set and hot glued into the shell and yes i tested it to make sure it would burn through a test half of a shell.

well the problem was the shell lifted perfectly butdid not go offin the air it came down to the ground and when i found it this morning i noticed that one of two things happened

 

1. the amount of lift i used might have blew the fuse to pieces causing it to not light the fuse and go off cause i did not see any spark trails following the shell upwards.  

 

2. well i dont know what the second reason would be but i do know that the fuse was sitting well into the lift charge.

 

 

Anyone have any speculations or ideas why it did not go off??

First off, did you use visco fuse? For my 3" shells I use 3/4" length of visco fuse for a 4 second delay, not a 3" length! If the fuse you have burns that fast then it may not be able to withstand the lift charge like you said.

 

If the fuse is getting ripped to shreds, then apply some wood glue, tape, or at least something to strengthen the outside of the fuse. On top of that, prime the end of the fuse. Both ends if you want an absolute guarantee on ignition. A little rub of BP slurry does great.

 

A possible theory is that the timing was way to long and the fuse outside of the shell may have still been burning when it crashed to the ground and got snuffed out, or broken off. Then again I wasn't there so I don't know.

 

Well the fuse I used is from Pyrocreations here is what I used.

 

http://www.pyrocreations.com/inc/sdetail/4114

 

The fuse is cut and shipped in 3 inch pieces and each 3" piece burns for 5 seconds but I cut it to shorten the burn time I needed which was for a 3 second burn.

 

I refused the shell but this time instead of using a cone shaped cup for the lift pouch I used a 2 1/4" long piece of cardboard tubing and I also slid the shell fuse inside of the stickymatch to make sure it would get direct flame and put it all together and when i set it off this time it went up and the shell burst so i think i may have corrected the problem but will find out tonight when i launch another shell.

[justanotherpyro]

The chinese stuff is not as sturdy as american visco. It probably blew the fuse to shreds, and extinguished the flame. What you could try is rolling a piece of kraft, or regular paper that has been thinly coated in glue around the outside of the fuse that is going to take the shock of the lift. Don't forget to prime the end with BP, that is a very important step.

[hst45]

Viziers, if you haven't yet, try a cross-match on the take-fire side of the visco. Cut a slit lengthwise in the visco with a shapr razorknofe, but don't cut it through to the end. Next, take a small piece of blackmatch and feed it through this hole. I put a wrap of masking tape on one end of the blackmatch to act like the end of a shoelace to start the blackmatch to slip through the hole. (If you don't do this you'll be trying to push a rope through a keyhole! ) Once it's through, cut down each end so the whole deal is maybe an inch long.

 

You might need to change the length of your fuse since the fire now starts at the junction of blackmatch and visco streets. I don't worry about cross-match on the inside of the shell, I just make sure to keep at least 1 gram of flash at the end of the fuse. Good luck with tonights shell. Enjoy!

[justanotherpyro]

Cross matching is wasted effort on visco. Cut at a 45 degree angle and prime with a blob of Bp slurry with 5% dexrrin.