Aerial Shells

[psyco_1322]

Here is some shells I made awhile back. One is a black smoke shell, one is a Win20 that had 3 small rising shells on it that just went pop, the other is a radiant green shell that had a horrible break.

 

http://www.apcforum.net/files/S4021847.AVI - Radiant Green w/ Mg in lift.

 

http://www.apcforum.net/files/S4021846.AVI - Win20 w/ Ti in lift.

 

http://www.apcforum.net/files/S4021845.AVI - Smoke

 

 

Im guessing that the problem is that he used spherical magnalium, didnt even know hey made that. Reactivity may have been the issue. The size should have been fine. I used 325 in the above shell and it burns about the same as 200. All chems are fine powders, the only thing that wasnt was the KNO3 and that went through the coffee grinder.

[pudidotdk]

The smoke shell was very "schweet", what was the formula ?

[psyco_1322]

Ya that was kinda wierd sounding. I sound like some yanky. I was excited.

 

It was some of Firefox's black Ninja FX smoke that I binded with NC laqcuer and them primed with bp. Thats it, the stuff kinda burnt slow to start with so I thought it might make good stars and it did.

[oskarchem]

So I set of my shell yesturday, but it didn't burst poperly... but made a pretty nice effect anyway...So I will continue on making them.

[Mumbles]

Thats because they don't make spherical magnalium to my knowledge.

 

I'd say milling was the problem. These things really arn't incredibly mesh dependant as far as the metal. Still you should have gotten more of an effect than you did. Not sure what to tell you besides to try it without milling the components together next time perhaps.

[psyco_1322]

Oh and here is my flaming shit shell thats all screwed up. Gotta accidently add 100g extra KNO3 to the 300g of comp to get it to burn up the stars. But it looked nice and went out right before hitting the ground. Oh and on the lift I swabbed the inside of the cup with PVC cement and shoot the Ti around in it, This was before the Ti salute ring idea was talked about. Not sure what I was going for but a more equal spray of sparks. The rising effect didnt light. Grrr. But I like my labels.

 

http://www.apcforum.net/files/S4023457.JPG - Shell pic

 

http://www.apcforum.net/files/S4023459.AVI - Video

 

http://www.apcforum.net/files/S4023456.JPG - Some 1/2" Lancaster Electric Streamer stars for a 4" coming up, maybe a new years shell if I get on it.

 

On the not of these stars, I would like them to burn long enough to get them out there. The problem is its practically bound flash, not really, and they burn quite fast. Im thinking if I prime the whole star in bp than they are going to get burnt up pretty fast. Thought about wraping them and only priming the ends that would face in, kinda like a crossette star. Sugestions?

[qwezxc12]

I've tried taping up the bottom and sides of larger (3/4"+) cylindrical stars/comets in some of my shells. It's about balancing light output and burn rate...you'll need a bright star if it's supposed to look good while effectively being a one-sided pillbox star. The 1" Emerald green comets in the 4in palm shell I attempted were taped, but their light output was too dim and their tail too sparse for my taste.

 

The closest thing I've gotten to success is taped 1" Mg curl comets in a 6in shell, but they still aren't the effect I wanted. I'm still working on it.

 

If you can deal with the tedium of taping or Elmer's glue dipping your stars, give it a try.

 

BTW, I like the metals in the lift - cool and easy.

[psyco_1322]

Im just gonna prime the whole star and shot em, if it works cool, if not sad.

 

Thanks for the compliment on the lift. It does give a niice little star mine effect.

[crazyboy25]

OK i am making my first 4" cylindrical shell. when i spiked it it looked like the string was a little small. i used this string to spike my 2" cylindrical shells so i thought it might be fine for this one so what do you guys think should i cut this off and get a bigger string or will this do fine?

 

 

http://i179.photobucket.com/albums/w318/cr...221pyro0001.jpg

[oskarchem]

I like the metals in your lift aswell, but since I am new in shell building, should my BP for the lift be corned of can it be just meal?

[Mumbles]

BP has to be corned.

 

Crazyboy, that shell looks fine to me. The string should be fine. I like hemp twine personally.

 

Anyway, something I noticed. It sure looks like you started and ended the horizontal spikings with hot glue. I can only imagine you did the same with the verticals. This is going to result in a very poor break. It should all be one continuous string. Pictures would make this much easier to describe.

 

You should tie the string off to the fuse, or around the shell like so:

http://www.passfire.com/archives/issue2_9/malta26.jpg

 

I normally do it like the picture. It makes it easier to start spiking, and doesn't put as much stress on the fuse.

 

Spike as normal. I normally off center spike to keep the fuse from piling up around the time fuse. I've accidentally sliced my spiking strings while splitting the fuse on multiple occasions.

 

After that, you have to have a slow spiral down to the bottom.

http://www.passfire.com/archives/issue1_3/spike4.jpg

 

There is a trick to doing this. Say you are looking at the shell from the fuse end, and just completed your last vertical. Go accross the shell as if you are going to spike it again. The string should be next to the first vertical. Say you are going to spiral down counter-clockwise as you are looking at the fused end. Lay the string on the left side of the vertical. Then start spiraling it down. The vertical helps to hold the string in place as you are winding down. It should take maybe 1/2 to 3/4 of a turn to reach the bottom. Put a horizontal over the spiral to hold it in place, and spike horizontally as normal. When you get to the top, put around 3 bands next to each other.

 

Now is when you tie it off. There are two ways. The first is to slide it under a vertical, and glue it into place. Personally, I don't like this. What I do is slide the string under the spiral you made down. Then I can pull back on it and make everything very tight. I tie it off with a knot. The 3 bands at the top are to allow ample string for tying it off.

 

A hint about getting string under verticals. Do it on the top of the shell. You can use a pencil or something to slide the string under on the top, then slide it down, and work it over the edge to get it down on the side to tie/glue off.

[crazyboy25]

ok thanks alot mumbles i re spiled my shell and now i plan on pasting it i think i know what to do i just want to clarify:

 

 

 

1. make wheat paste using pudi's tutorial

 

2. cut strips of kraft paper (from a brown paper lunch bag)

 

3. dip the strips in the wheat paste wipe off the wheat paste with fingers so it is a wet strip with a little paste on it

 

 

4. paste about 17 layers on my shell.

 

5. let dry.

 

 

does anyone see any problems/corrections with this method?

[psyco_1322]

Canisters shells are wrapped in a continuous sheet of paper, not strips like a ball shell is. Dont have time to elaborate, sorry. But at least you know not to do it.

[Pretty green flame]

Psycho is right. Cut a lenght of craft sufficient to go 4 turns around the shell and wide enough so it overlaps a little more than half a diameter on both sides. Roll it up, tear the overlapping craft into flaps and fold them down.

 

For easer pasting you can wrap shorter lenghts of craft onto the shell. For example, the craft should be long enough to go 2 full turns around the shell. This operation is then repeated again untill you have 4 turns of craft on your shell.

[Mumbles]

I wouldn't go 4 full turns with one sheet of paper. The paper would have to be 4 feet long. Do two 24" segments. With bigger shells there are slightly different methods I employ, but not really applicable here. You should have 2 24" long sheets, and they should be height + 4.5" If your shell is 4" tall, the paper should be 24x8.5" This will allow for some over lap on the bottom of the shell. This gives a little padding and lots of fire proofing. Yes, there should be overlap on the bottom. Just roll two pieces of paper on, or you can let one dry, and then roll the second. I only do multiple pastings starting with 5" though.

[crazyboy25]

all right thanks alot just one more question how would i use the wheat paste to get the paper on the shell

 

 

 

should i soak the strips in ithe paste? paint it on the shell? wipe it on the strips then apply them to the shell?

 

 

thanks for any help you can give i will try to post a video if i get to finish it in time

[Pretty green flame]

Lay a sheet of craft on the work bench and paste it with wheat paste on both sides, leave it for a couple of minutes so the paste get's into the paper and makes it more pliable (Alternatively, you could paste it and...emm how do you say...form it into a ball and squezze it a bit so the you break the grain of the paper and let the paste really get into the fibres, then spread it out on the work bench again)

 

Anyway, when it's soaked through just roll it up onto the shell.

[crazyboy25]

ok thanks a bunch i'll go do that im using kraft paper from brown shopping bags that should work right?

[Pretty green flame]

ok thanks a bunch i'll go do that im using kraft paper from brown shopping bags that should work right?

Should work quite well.

 

Make sure you catch this bad boy in action

[crazyboy25]

ok my shell is almost done i finished pasting all i really need to do is add a lift cup, fuse and attach the comet

 

 

but as i was putting my shell in the mortar to test the fit i realized it was too small!!!

 

 

what do i do?!?! its about 1/4" gap on either side of the shell way too big what can i do?

 

 

i was thinking about wrapping it in newspaper then taping that on it. i could hot glue on a strip of cardboard what do you think?

[oskarchem]

Well you could paste it more, but that would increase the weight...

[psyco_1322]

Thats not that bad, maybe for a canister and for a homemade shell. Damn I see them commercial display shells and the gaps they have scare me! You could just add a band at the top and bottom of the shell, kinda like a sealing ring for gasses, or just take some thick cardboard as you said and wrap it around the shell. It'll get blown off fduring launch and will add no extra confinment. If you've took a look at the 1.4g Excaliber canister shells thats what they do. Or just increase your lift charge and shoot it the way it is.

[Mumbles]

If you have a 1/4" gap on both sides of your shell you did something very wrong in making it. The end disks themselves should be 3.5" wide, which is 1/4" on either side. If you mean you have a 1/4" gap total (IE shell is 3.75" wide) you are fine. The leader and dry wrapping will tighten it up a bit. Honestly, even if it's 1/4" on each side, I think you'd still be fine firing it. The fast fix is to wrap news paper around it, or put a big wad of news paper between the shell and the lift. It will act as a bit of a sabot.

[Spider]

hi there

I actually have the same problem with my 120mm shells. theres a 1cm gap in total. what do you think about making a newspaper"snake" and wraping it aequatorialy round the shell and then pasting again one layer?

 

and the other problem, the mortar:

it's a ~7mm strong plastic mortar (most probably PE, could also be HDPE). do you think this one holds 5 shots of about 500g shells? i think i would take 35 to 40g of quite fast BP as lift. that should be ok?

 

Thanks and have a nice xmas

Spider

PS: excuse my english^^

[hst45]

and the other problem, the mortar:

it's a ~7mm strong plastic mortar (most probably PE, could also be HDPE). do you think this one holds 5 shots of about 500g shells? i think i would take 35 to 40g of quite fast BP as lift. that should be ok?

If you not sure of the composition of the tube I would go for secondary containment to minimize schrapnel potential. I'd play it safe and either:

 

1) Bury it. Put the tube in a box and fill the box with sand, or

 

2) Wrap it in a blanket; one that you're not very fond off since it will suffer some burns, and hold it in place with some stout rope. An improvised blast mat.

 

The BEST course of action would of course be to use HDPE, but if you can't be sure at least minimize the risk.

 

By the way, your English is fine. You ask good questions in an intelligent way, and make yourself easily understood.

 

Merry Christmas, back at 'ya.