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arm
May 19th, 2003, 09:48 AM
I was wondering, has anybody actually made a really interesting pyrotechnic device apart from the usual old ground salutes and rockets. Not that these items arent fun, its just the're a bit 'samey'. I mean once you've got good BP/flash, its pretty easy to make a bang.

What i want to know is, has anyone made anything like shells for example???? The most impressive thing i've launched out of a mortar is just stars. My pyro dream would be make a larger bore shell with a really nice effect like golden willow/blue peony. Around 2-3 inches in bore would be nice. This would be especially good since aerial shells have banned in the UK after some stupid fuck blew his head off with one.

So, has anyone been really creative and done something worthy of the term 'pyrotechnics'?

a_bab
May 19th, 2003, 10:25 AM
I've done several pyrotechnical devices including salutes, star mines, flares, etc. This year I finally made some shells. It's not that hard, but for me it was as I didn't had BP, so I used Al/Pb3O4 mix instead (both for lifting and for breaking). As for the stars I used potassium chlorate/sugar mix plus barium carbonate (green), strontium carbonate (red) and CuCl (blue). I used visco fuse from lots of crappy rockets (small whistle rochets), and ping pong balls for the casing, so the shells were quite small, but very effective, I can assure you. I've made about 30 with the aid of a friend in about four hours, with various colors, including willow tree (it worked wonderfull, the secret is to use lampblack). I tried to make some patterns, but with such a size you cannot talk about patterns. I also filled about 5 shells with AP and these worked too (loud). I cannot tell you how many *extensive* tests I did to find the optimal amount of lifting powder (raging between the break of the mortar and a 5 metters flight). The maximum high was about 30 metters or so. Then, I did several mistakes involving the fuse. The fuse MUST be insulated very well because the flame from the lifting powder can (and it will) enter in the shell around the fuse, so you'll end up with a flower pot.

I used a HDPE tube as mortar and after a few shots it failed due to the heat. For the next year I am planning to make bigger shells, mainly with potassium nitrate as oxydiser (for the stars and for the breaking powder). For the mortars I'll use cardboard tubes, arranged in a cake.

I have some movies from my shells if you are interested. I am planning also to make some page about how these shells could be done.

arm
May 19th, 2003, 12:16 PM
Aluminium/Lead Tetraoxide - interesting composition for burst/lift, bloody poisonous. Would like to see the movies, can you post links, or do you want my (anonymous) email address?

Heres a couple of vids of some nice homemade shells, look about 3-4 inches to me:

Glitter1 (http://www.redhouse.force9.co.uk/dexterspage/videos/glitter.WMV)

Glitter2 (http://www.redhouse.force9.co.uk/dexterspage/videos/glitter2.WMV)

Silver (http://www.redhouse.force9.co.uk/dexterspage/videos/shell.WMV)

I love the sound of big mortar firing, sort of a deep thump sound:)

Guerilla
May 21st, 2003, 09:31 AM
Nice clips arm. Could you tell more about those shells (star comps, shell diameter and material, bursting charges etc..)?

My pyro experiments have been so far salutes, colored smokes and stars that I've used in starmines and in rocket payloads, but I haven't yet tried any bigger shells. The stars have been chlorate/carbonate or nitrate based, for blue ones I use CuO as a colouring agent. KClO3/SrCO3/Sugar looks good but my BaCO3 based stars have always burnt with a very pale green..

As for lifting and shell bursting charges, the H3 formula (KClO3/C) should work great in place of BP, it's also easy and fast to make.

I don't know would it be a stupid idea to try shooting some small (2") shells from a 'spudgun mortar'? :p

arm
May 21st, 2003, 10:28 AM
Yeah guerilla, the're not my shells by the way (Wish they were:( ) and the guys website that i got them from doesnt say much about them either. From what i can tell they are round 4 inch shells made from plastic hemis. The break is flash from the looks of the photos on the dudes site.

The site is:

www.redhouse.force9.co.uk/dexterspage/ (http://www.redhouse.force9.co.uk/dexterspage/)

I always have trouble with certain colours - the slightest sodium content can really fuck up the colours. Dont you need chlorine donors like PVC or parlon to form MCl+ in the flame.

H3 Sounds good to me, the only reason i dont use it so much is the chlorates - they always scare the pants off me. There are so many stories on rec.pyrotechnics of people getting killed even when using them sensibly.

As for the potato cannon mortar - should be ok as long as the plastic's good and thick. I'd still be long way from it went it goes off though!

Guerilla
May 21st, 2003, 03:10 PM
Dont you need chlorine donors like PVC or parlon to form MCl+ in the flame.

Apparently the needed chlorine is released from chlorate, although most of the chlorate usually decomposes to oxygen and potassium chloride. I think the fuel plays a pretty significant role in how much chlorine ends up for the metal.. The other duty of the chlorine donor is to decrease the formation of MOH- (don't ask why, it has something to do with the wavelenghts. at least in the case of Cu, Cl- is only one that emits blue..). If you're looking for separate chlorine donors, parlon is far the best due to high chlorine content, but NH4Cl has also been used in the first coloured fire comps..

H3 Sounds good to me, the only reason i dont use it so much is the chlorates - they always scare the pants off me. There are so many stories on rec.pyrotechnics of people getting killed even when using them sensibly.

Yes, the chlorate mixtures must be handled with respect. Nevertheless H3 is one of the safest chlorate mixtures there is. Mix it with the diapering method, avoid friction and keep it away from other chems, especially from sulfur. You can take a small batch and hit it with a hammer and rub between sandpaper to see how much it can take it..

Sparky
May 21st, 2003, 10:08 PM
My main interest is pyrotechnics, unlike most people here who are mostly interested in HEs. I've dreamed of making lots of stingers, smokes, mines, roman candles, ground spinners, salutes and lots of other stuff. Currently my favorite dream is making film cannister shells. Generally they are quite good but I think film cannisters are too weak to provide enough confinement for a symmetrical break. When I dreamed of trying flash for burst the stars didn't light and with whistle they lit but not that well (they were well primed with BP over a layer of "red gum prime"). It's too bad pyrotechnics generally need lots of specialized chemicals, especially the many different mesh sizes of metals. It made it hard for me to aquire all these thing so that I could start dreaming but eventually I got most of the common ones.

I recently had a dream: I set off 9 different film cannister shells. I tried spiking (wrapping to reinforce) some of them with duct tape and packing tape, and it makes them much louder but not symmetrical. I used the black film cannisters, not the translucent ones, I used 2.3 grams of lift and 1 gram of fine bp with a touch of fine Mg for burst. After trying quite a few compositions I decided that these are so far my favorite colors:

Blue star #70 :
Potassium perchlorate 63.80%
Red gum 9.50%
Cupric oxide 12.90%
Parlon 13.80%
Dextrin additional 4.00%


Ruby red mgAl
strontium nitrate 50
parlon 18
magnalium granular -325 mesh 12
potassuim perchlorate 8
charcoal airfloat 5
sulfur 5
dextrin 5
red gum 2

Both are very deep intense colors and go well together. I used fine ball milled charcoal because I don't have any air float. I primed both with lots of "red gum prime" (from Wouter's database I think) and then mill dust. I certainly like these colored stars but I think the effect stars are more interesting, though the mesh size is generally quite important for effect stars so they are in some ways harder to make. I haven't made any green stars since I haven't wanted to dream about posionous barium compounds (BTW 6/4 BaSO4/fine Mg burns like good flash when well mixed!). I might dream about some some barium carbonate stars in a while. The favorite shell I have ever dreamed of making was actually a simple willow shell, and used only black powder ingredients. Nothing but charcoal sparks gets monotonous after a while though. I have been looking around for some nice aluminum effects and found a very simple 'flitter' star. I found this in Introductory Practical Pyrotechnics:

Silver Flitter Blesser:
potassium perchlorate 33
dark aluminum 61
dextrin 6
bind with 25% alcohol

Generally I've found blesser's formulas to be less than satisfactory and this was kind of the same. There is nothing flittery about it, which is no surprise since there is no coarse aluminum in it. It is an intense bright white star that burns fast. But by adding 20 parts 50-150 mesh granular Al (that's what I had on hand) it is still a fast burning star that propells itself vigorously on the ground, but it seems to have a much bigger flame envelope and gives nice white sparks. Not what I would call flitter, but pretty cool. These stars make an intense mine and burn fast so they don't come back down and hit the ground.

I assemble the FC shells with hot glue and use an aluminum foil burst bag to hold the burst. The visco is wrapped in tin foil to make sure it lights the lift at the right time and not sooner. My dream mortar is a 1.5" piece of ABS pipe which must be quite strong because it survived fully intact from a flowerpot with 2 grams of whistle burst in the shell. The whistle burst was relatively slow as whistle goes since it was 7/3 kclo4/k benzoate and the benzoate was kind of coarse. The flowerpot was because I forgot to put the lift in :o not because of blowthrough. I have dreamt of shell having an early break just after it came out of the mortar but it looked like a mine and nobody watching even knew anything went wrong.

As for using a spudgun instead of a mortar, it would be tricky. Shells shot from a mortar with black powder can fit quite loosely, but spudguns are fussy when it comes to the projectile fitting snugly. I think that it may not go very high unless it fits quite well or you use a washer. It could land nearby which would be dangerous. Also, I have dreamed that spudguns do not light fuses nearly as easily as a black powder mortar does so you may have a problem with that.

EP
May 21st, 2003, 11:34 PM
My interest was originally pyrotechnics, and while HE has been distracting me quite a bit lately ;) I'm hoping to get back to work on real fireworks. I just got a ball mill a few days ago along with black powder chems and a few coloring agents. I'd start out with a fountain, but I lack suitable tubes so I'll probably try small star mines first, I've always like those...

arm
May 22nd, 2003, 01:45 PM
Hi

The main problem i have is getting the chems. I can get Potassium Chlorate, Potassium Nitrate, Strontium and Barium Carbonates, Copper Oxide but what i really want is Potassium Perchlorate. The only way i'd be able to get it is from a chemical supplier and i get the feeling they are not going to be too inclined to help me out. I really hate ringing round and having to talk a load off bollocks to get stuff.

Anyway, when my new ball mill arrives in a few days time i'm going to have a go at milling some spherical aluminium into smaller flakes.

Guerilla, sparky & a_bab: pretty impressive stuff you've managed to do there, nice!

a_bab
May 23rd, 2003, 07:32 AM
Well, these are two of my movies. Unfortunately the guy who was supposed to film the scenes screwed up nearly all the stuff, so sorry. That's nearly all I got.

Blue shell (http://www25.brinkster.com/uploads777/Access/blue.mdb)
red shell (http://www25.brinkster.com/uploads777/Access/red.mdb)

Download the files and rename the extention as avi.

arm
May 23rd, 2003, 04:47 PM
Shit,

ive tried the video in Media player, Real Player and the Quicktime player and all i get is sound without pics.........Anyone else got this problem.

Sounds good a_bab!!!

a_bab
May 23rd, 2003, 05:20 PM
The movie it's divx 4.12, so you need to install the DivX codec in order to see the movie.

There are a few mistakes in the shells design really, nothing much to see. The stars are burning far too fast, the lifting powder flash is huge (Pb3O4/Al mix), no clear pattern, etc. Next year it'll be better !

arm
May 23rd, 2003, 05:47 PM
Hey, still better than nothing (ie me).:)

Like you said you just need to slow down those stars, and have a better lift charge. Flash breaks are necessary for smaller shells (they look cool too).

Pretty darn good, i liked the blue. Tell that buddy of yours to work on the camera skills.;)

Guerilla
May 26th, 2003, 05:22 PM
Yeah not bad a_bab.. I too have problems in getting some essential chems, such as perchlorate, magnesium and aluminum powders. Especially the lack of those metal powders annoys me because it keeps me away from flash powders. Potassium perchlorate isn't too hard to produce by electrolysis but it's a pain in the arse since I have to first synthethise chlorate for it.

..okay, enough self-pitying. I think I will try shooting some shells with the spudgun, as soon as I get it constructed. I'll go with some sort of a washer and use a bp prime on the end of the fuse to aid ignition, will see how it performs.

a_bab
May 27th, 2003, 05:07 PM
Guerilla, I *might* have an answer to your lack of metal powders. Assuming that you can get magnesium (and you'll do if you're really interested), you can try to make a verry brittle AlMg alloy (magnallium), which can be powdered easily by the means of a blender.

Details concerning the alloy here (http://www.redhouse.force9.co.uk/dexterspage/mgal.htm)
Details concerning possible sources of magnesium metal along with some interesting use :D here (http://www.burningart.com/meico/valhalla/mag.html)

arm
May 27th, 2003, 08:23 PM
To all the shell makers out there:

What type of shells do you prefer, Spherical or cylindrical? I had a go at making a 3 inch round shell casing out of paper mache. It worked well but took too long by far - far too long even for a more symmetrical break. I then tried a 3 inch cylinder shell and did it in a couple of minutes. The only difficult bit was the end plugs. Although, it would need spiking after filling.

So, whats your prefered way of shell making?

Bryan
May 27th, 2003, 10:50 PM
MY main hobby is pyrotechnics. My preferred way of shell making is cylinder, as they are much easier and require less skill to make. I am currently trying to mix pyrotechnics with HE's as I think they could enhance visual effects a lot, eg more powerfull shell breaks... With small shells If the flash from the burst it lowering visibility of the stars, use loose whistle mix, it still flashes, but not as much.

Bryan

a_bab
May 28th, 2003, 06:16 AM
Using HE in shells will do nothing but turning the stars into dust. I tried with AP and the only effect was a perfect maroon.

Guerilla
May 29th, 2003, 07:11 AM
As for the MgAl alloy, thanks for the links a_bab, I've been aware of that method but I've been too lazy to look for magnesium from scrap metals. Now that I saw the sources where I could get it (hot water boilers, engine cases..) I think I'll drag myself to a scrap yard someday. :)

I have read of people making Al powder by heating aluminium foil red hot and damping in water, it becomes very brittle and easy to powder. It would hardly be sufficient for any flash powder due to the high oxide content that the heating surely makes, but it might find use in some flares, fountains, stars etc.. Has anybody ever tried this?

yt2095
July 20th, 2003, 03:13 PM
a mortar shell based question,

when loading a spherical shell into the launch tube (delay fuse down) how does one garauntee that the shell with a stars patern inside IE/ a smiley face " :) " will be the correct way up and not upside down when it bursts?

i can see how it could easily be acheived using a rocket to deploy such a shell. or how a mortar containing a non critical patern IE/ concentric colored circles or half circles could be deployed without concern.
but a letter or a number, a smiley or a heart shape???

could it ba stabiliser fins perhaps? or maybe a spin stabilisation?
i`de like to progress into this area, but as yet this remains to me a mystery, any help appreciated :)

Sparky
July 20th, 2003, 11:49 PM
Often there is no mechanism used to make sure that the design burst the right way up. Instead a volley of shells is sent so some of them end up being right side up. This was recently mentioned on rec.pyrotechnics by Mike Swisher. In the same thread, Terry Wilder said something about a "hangered -roped" attachment used in some Japanese shells to orient them. But he doesn't describe what it is.

Personally if I made a shell meant to make a design then I would put a streamer on the bottom to orient it the right way. The streamer would flap in the wind and create drag to right the shell. At least it would be right side up even if it is not facing a certain way. In big shows of course the crowd usually surrounds the display so the fact that it does not face a certain way doesn't really matter.

yt2095
July 21st, 2003, 09:12 AM
Excellent idea!
I`m surprised I never considered that, simple and effective :)

the next shell case I make, I`ll incorporate the braiding from some coax cable and feather the end say the last 8 inch or so.
Thnx for the idea :)

Pyroboy
July 23rd, 2003, 02:10 PM
Pyrotechnics is mostly what I'm into these days. For a while it was HE but the whole terrorism bullshit and the lack of a place to set them off kind of put me back into pyro. I started with 3" cylindrical shells but now prefer spherical. My main problem is the chlorine donor, here in OZ we don't have anything like Skylighter. I was wondering if anyone has found a source for Parlon other than from a pyro supplies company? I could use PVC but it would take hours to powder just enough for a small batch of stars!

I now plan to go up in shell size from 3" to 5" so some colored stars would be nice as apposed to the plane old white or charcoal streamer.

Matt.

Pyroboy
July 27th, 2003, 03:20 AM
After searching for some Australian companies and even some chemical supplies companies all I've been able to find is a chlorinated rubber paint. From what I can tell it's chlorinated rubber mixed with who knows what else. I'm not holding my breath that it could be used. Crazy Swede did you contact the company that uses it in their paint and ask for the pure stuff before it's added?

The paint I've found says it contains
Xylene 60%
Chlorinated rubber 10%
chlorinated plasticizers 10%

It needs to be dissolved in Xylene anyway so I suppose it could be a bonus.
Here's a link to one of the sites I found
http://www.altexcoatings.co.nz/3500_pds.htm

*update*
I've just found a source! They also sell PVC and lots of other goodies :)

Once I've got all the Parlon I need then I'll give out the source.

Stay green, Matt.

EP
August 2nd, 2003, 04:10 AM
I've finally stockpiled enough chems to make just about anything I want and am finally getting into making real fireworks. I made my first stars the other day and put them in a mine. Here is the video, I think a lot of the stars broke up but it was still cool. There is a basketball hoop visible in one frame for scale:
http://www.geocities.com/extremepyro2/chrysanthemum6mine1.MOV

Pyroboy
August 2nd, 2003, 12:24 PM
Very nice, the lift charge gave a nice sized fireball. I have a few questions... Was it just homemade bp? What composition was used for the stars, willow charcoal? and how were they prepared? What was the I.D of the mine?

Matt.

yt2095
August 2nd, 2003, 12:42 PM
EP,

VERY nice! as Pyroboy said, a Nice fire ball too! intentional I figure.

as for the stars breaking up, well.... it`s probably just as well that they did, because you`de have to go a long way to improve what you did :) and anyway, I think it sucks when unburnt stars hit the floor and burn like waste.
I happen to like the tinier particles at ground level.
I have same questions as Pyroboy and also what did you use as the mine casing (a re-usable sort or a one-shot?)

Sparky
August 2nd, 2003, 10:10 PM
Wow, I have to agree with everyone else - that's a pretty sweet mine. So, I don't suppose you could share any details about it, eh :). Kind of stars and formula, prime, lift charge, mortar used, if you used a plug or perforated disk, method of construction... that sort of thing would be most interesting.

yt2095
August 3rd, 2003, 12:33 PM
I`m hoping that someone else may have seen or read about this ancient method (Japanesse) of making stars.

According to the documentary I watched, something similar to a cement mixer was used, in fact I think it actualy was.
In it went slightly damp but seperated Rice! :)
as the rice was tumbling, the star powder was added, as it rotated the rice became coated (naturaly). this was done to several layers till each star was about the size of a marble 1 to 1.5 Cms diameter. I`m guessing here that multi-color layers of powder could be added to make color transition stars? (I love to see them) :D

I`m wondering now, if some kind of modified (slowed down) ball mill could be used to do the same thing?

All the Best :)

Edit: they were dried in the sun on a bamboo mat, a bit like a huge Sushi rolling mat.

EP
August 4th, 2003, 02:45 AM
Sure, I can give more details! This is the formula used:

Chrysanthemum 6 streamer:

KNO3 55
sulfur 7
charcoal 33
dextrin 5
bind with 25% alcohol

I didn't measure how much BP (homemade) I used, it was five or six scoops from a tablespoon, perhaps more than I needed but it looked cool. :D It was fired from 3 inch HDPE, I made it pretty much the same as you see here:

http://members.aol.com/liteboltt/mine1.html

yt2095 - What you are describing is more or less the same method used to make round stars today for fireworks. Read this:

http://huizen.dds.nl/~wfvisser/EN/stars_round_EN.html

Agent Blak
August 4th, 2003, 05:55 AM
I like the Simple Fuse on dexters page. It works realy well and you can coat it with NC Laquer to make it a little better.

The nicest thing about the fuse is it is a core burner; so you can hot glue or epoxy around it, without risking duds.

Rat Bastard
August 4th, 2003, 09:07 PM
Hey, that gives me an idea..... EP, I know the stars broke up, (those were cut stars right?) but do you think you could coat them with a little NC laquer, and dust with bp before it drys? that might hold them together. Or, would a little more dextrin in the comp help it...

0EZ0
August 4th, 2003, 09:46 PM
If the completed comp is crumbly and does not hold together well, then you are not using enough dextrin binder. When dry, the star pellets should be nice and solid. Almost like chunks of chalk. Well maybe not that solid, but close. Search on rec.pyrotechnics for more information on the amount of binder needed to produce hard, non-crumbling stars. Same goes with rocket fuel grains if you use dextrine as a binder. As for the solvent most use a 20/80% by volume ethanol to water mix. Although you will find it may vary from comp to comp.

EP
August 5th, 2003, 01:14 AM
I'll try more dextrin next time, but I don't think that's the problem because the formula is from a very respected source. Perhaps they are intended more for pumped stars that would be stronger? I could try NC if I had it, but I don't have a good source. Anyway, I'll play around with it some more.

metal dragon
August 5th, 2003, 05:54 AM
Have you ever considered pressed stars? They rammed in a small tube and then they are pushed out and they are ready to fire. I use the formula 30 KNO3/ 20 sugar/ 25Charcoal crumbs. Hope this helps

Mark

Pyroboy
August 5th, 2003, 09:46 AM
For my charcoal streamer stars I use anywhere from 2 - 5% dextrin and a 50/50 ethanol/water mix. I allow them to dry for a couple of days and they end up rock hard. They never break up even in a shell with a flash burst. I think your mine looked great because some of the stars broke up, it gave a nice effect.

EP
August 23rd, 2003, 02:27 PM
Here are some pics and vids of mines I set off the other day:

Red mine frames:
http://www.geocities.com/extremepyro2/redmineframes.jpg

Red mine video:
http://www.geocities.com/extremepyro2/redmine.mov

Yellow mine frames:
http://www.geocities.com/extremepyro2/yellowmineframes.jpg

Yellow mine vid:
http://www.geocities.com/extremepyro2/yellowmine.mov

The yellow color wasn't that great so I'll have to work on it, also the stars were too big and some alsmost hit the ground...doh!

edit: grrrr...bandwidth exceeded...you'll have to wait a bit to see them.

Pyroboy
August 25th, 2003, 09:38 AM
I personally think the yellow mine looked the better one of the two. Because by the time the stars started to descend they spread out nice and wide. What were the formulas? What was the diameter of the stars? Cut or rolled?

I'm able to download the videos but not the pictures, I've tried yesterday and today.

EP
August 25th, 2003, 02:23 PM
Did you try copying and pasting the urls for the pics into the address bar? It works fine for me.

The stars for both were cut, the diameters were rather inconsistent but the yellow stars were far too large, some nearly hit the ground!

Red (Shimizu)

KClO4 66
Red gum 13
Strontium carbonate 12
Lampblack (or charcoal, I used charcoal) 2
PVC 2
Dextrin 5

bind with 25% alcohol

Yellow Shimizu

KClO4 68
red gum 18
NaNO3 7
charcoal 2
dextrin 5

bind with 25% alc

Bert
September 14th, 2003, 03:32 PM
I've made shells, mines, set pieces, wheels & etc.,
including the stars and bursts for the shells. I haven't
been too active in rockets as they aren't too widely
used in US displays anymore. But they were my
first projects as a teenager.

I don't think I'm allowed to post attachments at this stage of
my existence here. If/when I can, I have a few pics.

blindreeper
September 14th, 2003, 09:08 PM
Bert, do you mean post attachments like the mods do? Or post a link to a website or the like?
I don't have a clue how the mods post attachments but posting a link is ok as long as it is relevant...

Bert
September 15th, 2003, 11:24 AM
I mean, put a picture up here.

I don't have any of my digital photos of devices,
field set ups & etc. on a web site at this time.
We'll eventualy get some on our company site,
but it's kind of bare bones right now.

Also, I'm better with pyro than a computer.

Efraim_barkbit
September 15th, 2003, 01:02 PM
make a account on www.imagestation.com

Bert
September 16th, 2003, 12:16 PM
Thanks for the suggestion, Efraim.

Some pictures of 7" shell assembly (http://www.imagestation.com/album/?id=4289107595&idx=1)

The ruler in these shots for visual reference is 24".

I warn you, if you click on "view original", they're large.

And this is what it looks like when we're using these toys-

Field set ups (http://www.imagestation.com/album/?id=4289107219&congratulation_page=Y)
=============================

Crap. I just tried to look at these pics from my GF's
computer. Didn't realize they made you sign up for
there site before you could view these. Sorry dudes-

Any suggestions for better alternatives?

51K
September 26th, 2003, 02:34 PM
I have built a quantity of 4 inch shells and to make them fly so that they break one side or other
up, you need a piece of string and something else like a round plastic ring or weight. Basically
you attach the string, say 3 or 4 or 5 inches long to the top of the shell with the weight or ring
on the end of the string and when the lift charge flings the shell up into the air, the string with the
weight or ring on it creates drag or wind resistance and so guarantees more or less that the end
of the shell with the string hanging off of it is pointing downwards when the shell breaks. That is
how you can make the smiley face break right side up or have rings break any direction you
want - by carefully loading and then attaching the string piece to the appropriate part of the shell.

blindreeper
September 27th, 2003, 01:07 AM
Ok last night was my brothers 18th birthday party so I did a little somthing for the night.

http://www.geocities.com/blindreeper_chemistry/starmines.html

Down the bottom there are 4 videos, 3 granite starmines and one chrysanthemum streamer 6, the chrysanthemum ones were 3/4 inch cylindrical pumped stars. The granites ones were cut about 6x6mm and had a BP prime on them. In the videos they look pretty bad (colour wise) cause the camera is old. They were a much more vibrant darkish lime green colour with nice orange tails from the BP prime.

EDIT: These videos were taken from 50-75m away so they went pretty high. One or two of them (I did 5 all up only got 4 on tape) went higher than this huge gum tree which I worked out to be about 30m using tan

The ALL-MIGHTY
September 27th, 2003, 06:21 PM
I just got through making this tutorial thing on how to make home made mortars using film containers and bp substitute, actually the hardest material to get is fuse(which says something)... they go up about 100ft and are small (film containers) but look really cool, I'll post my tutorial link soon so if anyone has any interest in knowing what the hell i'm babbling about just stay tuned.

also if anyone needs 3" mortar tubes just do what i did, go down to wal-mart and ask to see the bag where they put all their film conatiners, in film development. when they bring it to you you can of course get a bunch of film containers, but sometimes they also have these 6" sections of tube that have a 1/4 wall thickness and a 3" inside diameter. i glued 4 of them together to get a pretty respectable mortar tube. i havn't tested them out yet due to a lack of projectile and i havn't convinced myself they can hold up to the pressure. if anyone wants to see if they work all power to ya, just be sure to post something to tell me if it worked or not... they always look at me like i'm crazy when i asked to see the bag, and when i walk out of the store with 10 tubes and a hand full of film containers....

Bert
September 27th, 2003, 07:13 PM
sometimes they also have these 6" sections of tube that have a 1/4 wall thickness and a 3" inside diameter. i glued 4 of them together to get a pretty respectable mortar tube. i havn't tested them out yet due to a lack of projectile and i havn't convinced myself they can hold up to the pressure.

I'm betting they won't. Maybe if you fiberglassed them or something-

Try to find the rolls that newsprint comes on. Look in dumpsters at jobsites where they're
doing roofing, sometimes I found a good tube there back when I was "experimenting".

Don't use PVC, it shatters after a couple of shots.

And mortars are legal. You can friggin' BUY them. It's the shells that you need a license for.

Spoz
April 19th, 2004, 04:19 AM
I just got through making this tutorial thing on how to make home made mortars [...] and when i walk out of the store with 10 tubes and a hand full of film containers....
I have had similar success using a piece of ribbon of an appropriate length, that way you dont need a weight which would be useful in certain situations. The heavier the projectile, the longer the ribbon will need to be, in order to be effective.

---------------------

Don't quote whole posts!

Rhadon

xxxplosive
August 25th, 2004, 03:05 PM
I am a Pyrotechnition by trade, so I make/shoot everything.

the bigest shells I have ever made/shot were 8", they consist of stars, reports, whistles,and anything else you could fit in a shell

for mines 4" colour stars are about the coolest ones I have made/shot

then there is low altitude pyro, Gerbs, Flash Bangs, line rockets, Confetti Air bursts

been doing this for a some time now.

if you need formulas for somthing pyrotechnics based just respond on this thread.

PS. I really like this forum I just found it less then a week ago, and I have found things, I didn't know about.
Phreak

justme
September 17th, 2004, 05:05 PM
Wow, another pyro is here.

I don't do this by trade, but am fully licensed (type 20). I've done shells, mines, gerbs, rockets, girandola, and of course an occasional salute (g) I recently got a video on bp rockets with i.d. of 2.25". The author used the mandrel wound fiberglass that they plumb filling stations with for the tube. I have personally seen these things fly and they are truly awesome.

I guess the only formulae that I seek are the ruby red and the brocade willow diadem from independence before they blew up.

justme

al93535
January 22nd, 2005, 07:15 PM
Here are three shells I made. The first is a 2 inch canister shell with 10 1.5 grams flash inserts. The second a 4 inch spherical shell with tigertail stars, and the third is a 4 inch with tigertail to a white star. Both of the 4 inchers were broke with 1 gram flash and BP coated rice crispies. My wife taped for me, we were about 120-150 feet away. Should have zoomed out, or got farther back. All homemade Black powder.


http://kkpaul.rpgames.de/picricsalt/myfirework011.mpg

http://kkpaul.rpgames.de/picricsalt/myfirework022.mpg

http://kkpaul.rpgames.de/picricsalt/myfirework033.mpg

What do you think?

Bert
January 23rd, 2005, 01:10 AM
What do you think?

The 2" fusilade shell is nice, maybe next time add a bottom shot timed just a second longer than the insert reports.

The second looks nice, good sphericality and the duration of the tails is good. Couldn't ask for more!

The third has an obvious "seam" in the pattern where stars are missing around where you joined the hemispheres. Probably looked good in the air anyway- If you can't avoid the "seam", perhaps add a ring of contrasting colored stars at the point where the hemis join and call it a "Saturn shell".

Please give details of how many layers of what kind of paper was used to paste along with the burst description, we really need to know both as they must be adjusted to fit each other- Or were those plastic hemis?

al93535
January 23rd, 2005, 02:28 AM
I think you are right Bert, next time I will add a bottom shot with my report insert shell.
I noticed that seam as well. The stars were packed well into each hemi, however at the top of each I couldn't get them right to the edge. Thats what caused the seam. The second shell didn't have a seam because I used larger stars and they fit right up to the edge. I think I like that one the best.
I am going to make a saturn shell next! A red ring, with a green planet. It should look good. I just finished making a 31 shot cake which has small shells, salutes, mines and crossette's. Which will be fired just before my next shells. I will have video of that for you guys as well.
Anyways, I used standard home made Black powder coated rise crispies in a 4 to 1 ratio. I then added 1 gram of 70/30 potassium perchlorate/5413 super-H 3 micron dark aluminum flash in the center before closing the shell.
The hemispheres were made from 70lb craft paper, (not virgin). I used a 3-5/8" plastic half sphere form I found around the house that was perfectly sized. I layered 3 sheets of kraft soaked in wood glue and water 5:1 over the plastic half to form one hemi. After the shell was loaded I pasted one strip of kraft around the seam. Next I pasted 4 layers of kraft strips perpindicular to the seam and let her dry.
BTW, those were my second, third and fourth shells I have made. Now I have chemicals for red, green, blue, glitter, granite spreaders, and more. The next ones will be Nice!! :D

Bert
January 23rd, 2005, 03:36 AM
I would suggest that you make the Saturn shell with slightly larger stars for the ring, and use metal fueled brighter, faster burning stars for the ring with organic fueled longer burning stars for the inner "planet". It also would be good to have a low light outer delay layer on the ring stars so they appear to "blink on" when the pattern is well developed.

When pasting, don't run the strips in the same orientation every time. I rotate the "poles" 90 degrees each time, and use this pattern:

1. Pole to pole, using the end with the time fuse and the end that will have the lifting ring

2. Turn the pattern 90 degrees, the poles are now on the seam

3. Turn the pattern 90 degrees again, poles are now on the seam at 90* to the last pasting.

4. Pick a point 45* between the seam and the fused end, run the next wraps from that point to the opposite side of the shell.

5. Do the same again, at 90* to the last wrap.

6. Rotate the shell 90* and put another wrap on at 90* to the last 2 wraps.

7. Rotate 90* and put the last wrap on.

So: you have applied 7 wraps altogether. 2 wraps have their end points on the "equator" (where you joined your hemis) 1 wrap goes "pole to pole" (from the fused end to the opposite end where you will attach your lifting ring)
4 more wraps in pairs at 90* intervals so that their are 4 end points on each hemisphere midway between the "equator" and the "poles".

This plan gives an equal strength everywhere and no excessive buildup of paper as can happen if you run all the wraps in the same direction.

I would also suggest that your home made shell hemis may be too strong and tough- I made them that way myself at one time, and the wood glue made them TOUGH. You want BRITTLE- It should tear apart into at LEAST 8 pieces, not 2. Try it with newsprint and wall paper paste for the hemis, and use the good kraft paper only for the paste wraps. Similarly, use wallpaper paste for pasting the shell.

Try one with 7 layers instead of 4, and leave the flash powder out. I have found that more paste wraps and less violent burst have given me better patterns and more complete star ignition- It does take longer, however. I have found that I can do 3 layers in a single pasting session, then must wait for the shell to completely dry before doing the next round of pasting. So a 7 layer shell is done in 3 goes- 1 layer the first time, then 3, then another 3. Takes 3 days if the humidity is low and I point a fan at it while it dries.

al93535
January 23rd, 2005, 04:25 AM
Thanks for the excellent information Bert, I really appreciate it. I will paste like that from now on. You really think the hemi's are too strong? What about the plastic ones sold at pyro sites, they have got to be stronger! I thought that the kraft and wood glue was pretty weak! Also, I was led to believe the extra kick from the flash powder would completely shred the shell casing. Wallpaper paste and newsprint for the hemi, and wallpaper paste and kraft for the wraps huh? I will try it on a test shell later this week maybe. I will try 7 layers as well. I really don't care how long it takes, as long as it's done right and gives spectacular results!
Also Bert, I was reading the flame colors thread and learned quite a bit from you, and others there. And I see you say that BaCo3 sucks for green. Well I got potassium perchlorate 55%, BaCo3 35% and sugar 10%. It burned well, but was pretty white. I also tried the same with copper chloride, and got white. I don't have a chlorine donor as I am waiting on saran resin. I thought I would at least get a small amount of color from the perchlorate's chlorine. I see others have tested the same way with the CuCl and got color, whats going on? Any ideas? Will the color fill out with the extra chlorine from the saran? I was thinking about adding the BaCo3 to nitric acid and drying it out for the nitrate.
Thanks again Bert,

Bert
January 24th, 2005, 01:44 PM
The hemis should be just strong enough to hold the components you load them with during assembly. Some of the best home made hemis I have seen are made from PULPED NEWSPAPER sucked into a mold with a vacuum cleaner. The paste wrap is virtually the entire strength of the shell, as it should be. You can find details of this method onpassfire.com (http://www.passfire.com/archives/issue4_6/issue4_6.asp)

Plastic shells must be either blown up with faster bursts such as whistle mix or flash, or taped with filament tape to make them break properly. I don't use plastic shells for much. I certainly experimented with them, but prefer paper for most things.

There are two approaches that people take with ball shells- Weak shell (plastic or paper with minimal pasting) combined with an overdriven burst such as KP, H3, whistle mix or slow flash-
Or a stronger shell relying on more layers of paste wraps and a slower burst such as scratch mix BP on rice hulls, cottonseeds, cork or whatever handy burst cores of appropriate size you can find. The stronger shell/slower burst when properly balanced (which includes the characteristics of the stars as well) gives superior break patterns and star ignition in my experience.

How far away are you from the composition when you burn it, and is it just loose or did you consolidate it into stars? Also, blues often don't look right on the ground, they need to be moving through the air to appear correctly.

I wouldn't waste nitric acid on making my own Barium nitrate! It's a cheap chemical and widely available, just buy some.

al93535
January 24th, 2005, 04:56 PM
Ok, more good information. I am going to try a newspaper hemi and try it next weekend. About the colors, I was maybe 15 feet away from a loose pile. Then I tested a 1/2 inch star in a star gun. The star was slightly more colored. But I wouldn't call it a colored star! I am hoping it will really color up with the saran resin chlorine donor.
BTW, everywhere I find barium nitrate it says unshippable. I have lots of nitric acid, in both 70% and 99.5%.
Thanks,

Bert
January 24th, 2005, 07:54 PM
The only good colors I get from perchlorate without additional Chlorine are Strontium red and Barium+Sodium yellow- It's pretty necessary to use a Chlorine donor for blue, purple and green. Always test a star formulation made up as specified and in the air before giving up on it as unimpressive... Try to look at a ground color test from 50 feet or more if you can. If you can't get far enough away, just glance past it quickly, don't stare at it for the whole burn.

Damn, I just looked at Skylighter and see what you mean. That sucks. I have a type 50 ATFE license and buy direct from Service Chemical so I had not noticed the change in deliverability. Be careful with the Barium nitrate particularly in solution. It's about as toxic as Arsenic. I know people who can't work with it even wearing filter masks and exam gloves, they get deathly ill just from skin absorption of the dust.

al93535
January 24th, 2005, 08:19 PM
Thats exactly what I thought, you need a good chlorine donor for colors other then red. I did try the strontium carbonate, sugar, and perchlorate and it gave a very nice red. I think I will try making the barium nitrate with the nitric acid, if you really think the nitrate is a much better green producting chemical.
I seen you say to check the color in the air before giving up in the flame colors thread. So thats what I did and I didn't see hardly any color. But I guess color testing will have to wait until I recieve saran.
Anyways, thanks for all your help Bert.

fishy1
March 24th, 2006, 01:09 PM
al93535,

The difference when using Ba(NO3)2 compared to the carbonate is huge. I make it by first making barium acetate with barium carbonate and vinager.

I then add KNO3 to the barium acetate solution and leave it to evapourate. As the water evapourates, crystals of barium nitrate precipitate out. When i have nearly the calculated amount of Ba(NO3)2 precipitated, there is a solution of potassium acetate left. I filter out the barium nitrate and after a few recrystalisations, the colour is pretty sweet when used in a comp with KCLO4 and shellac, made into stars it burns pretty nicely.

On a sidenote, has anyone tried the new blue:

82 Ammonium Perchlorate
18 Copper Benzoate

I'd like to try it but making NH4CLO4 is alot of work.

al93535
May 23rd, 2006, 05:29 AM
Well, I have not posted any of my recent pyro, so I have a few:

Construction pics of my 6" shell:

Here are the hemi's
http://img.photobucket.com/albums/v242/al93535/6hemi.jpg

Filled with stars:
http://img.photobucket.com/albums/v242/al93535/6filled.jpg

Burst:
http://img.photobucket.com/albums/v242/al93535/6burst.jpg

Inner petal:
http://img.photobucket.com/albums/v242/al93535/6innerpetal.jpg

Inner burst:
http://img.photobucket.com/albums/v242/al93535/6innerburst.jpg

40mm Rising shells:
http://img.photobucket.com/albums/v242/al93535/40mm.jpg

Finished:

http://img.photobucket.com/albums/v242/al93535/6inchfinish.jpg

http://img.photobucket.com/albums/v242/al93535/6inchfinish1.jpg

http://img.photobucket.com/albums/v242/al93535/6inchfinish2.jpg

The outter petal is green to red to dragons eggs, and the inner petal is winokur39 glitter. The outter petal should burn for 4 seconds, and the inner for 2.5. The rising shells will burst at 1.7 seconds, then every 1.4 seconds later. The main shell should ignite at 5.5 seconds.
Video:

http://www.apcforum.net/files/myfirework05.MPG


Here is a 4" glitter shell , winokur 39:

http://img.photobucket.com/albums/v242/al93535/4inchwin39glitter.jpg

Video:

http://www.apcforum.net/files/4win39.wmv

4" can shell with 22 hummers and 8 Ti salutes.

Here are the construction pics of the 4" can shell.

http://img.photobucket.com/albums/v242/al93535/inserts2.jpg

http://img.photobucket.com/albums/v242/al93535/can1.jpg

http://img.photobucket.com/albums/v242/al93535/can2.jpg

http://img.photobucket.com/albums/v242/al93535/can3.jpg

http://img.photobucket.com/albums/v242/al93535/can4.jpg

http://img.photobucket.com/albums/v242/al93535/can5.jpg

http://img.photobucket.com/albums/v242/al93535/can6.jpg

http://img.photobucket.com/albums/v242/al93535/can7.jpg

http://img.photobucket.com/albums/v242/al93535/canspike.jpg

http://img.photobucket.com/albums/v242/al93535/canfinished.jpg

And video:

http://www.apcforum.net/files/4canhummers.wmv

I just finished making a bigger better 4" can.

Ok here is my latest shell. It is a 4" can about 10" long, it weighs in at 1420 grams, and uses 93.3 grams of -6+12 lift powder.

There are 30 timed hummers, so 3 waves of 10, which will fire about half a second apart. Then I have 10 Titanium salutes (5 grams) which will go off after the last hummers. Then a 60 gram titanium bottom shot. This should be a fun shell!

And yes it was a bitch rolling 40 tubes, then ramming 30 of them with plugs and comp.

Inserts:

http://img.photobucket.com/albums/v242/al93535/insertsbs1.jpg

http://img.photobucket.com/albums/v242/al93535/insertsbs.jpg

Pasted and spiked:

http://img.photobucket.com/albums/v242/al93535/spikedcanbig.jpg

Finished:

http://img.photobucket.com/albums/v242/al93535/bigcan.jpg

I will light this one soon!

Bert
May 23rd, 2006, 12:56 PM
If you're interested in cylinder shells, have you got Pyrotechnica IX and/or XI- The Fulcanelli articles?

The 6" ball shell has well made stars. They come on and burn out uniformly as they should. The shell burst shows a "seam" running from 11 o'clock to 5 o'clock, especialy visible at fullest development. This is usualy caused by either leaving a small gap in between the stars in the 2 hemis on closing, or a weak place in the shell where the hemis are joined. Do you use plastic or masking tape to close the hemis before pasting? Perhaps use a pasted paper strip instead, and pay particular attention to the top layer of stars in each hemi. You should BARELY be able to get it to close. That being said, I've used worse shells than that one in my displays!

Your cylindrical inserts appear to perform well. The "can" shell appears to be breaking in a "hose break" rather than symetricaly in the video. Picky, picky, picky, I know! Many oriental attempts at cylinder shells perform no better, but traditional Italian style rolled and strung cylinder shells can be broken so symetricaly you would be amazed.

All the "photobucket" jpg's are unavailable.

al93535
May 23rd, 2006, 04:35 PM
Ok all the links have been fixed.

I have been advised to get those pyrotechnica issues. I just don't have the cash quite yet. Yes the seam on the 6" was made from the stars not being filled completely to the top in the hemi's. I am still trying to find a way to get the seam at the hemi's filled. I always use paper, and I paste with paper. I use one wrap of tape around the hemi's so that I can paste them. I have a few more ball shells now, that I have not lit yet, that I packed so tight I had to smack them with a stick to settle everything and close the hemi. I think will perform better. :) Practice makes perfect.

I know what I did wrong with the can shell, and this new one will fix that.

Chris The Great
May 24th, 2006, 12:34 AM
That is pretty damn impressive, I must say! The 6 inch shell was very cool, and the "seam" doesn't bother me at all, probably because I wouldn't even come close to doing as well if I tried it.

Bert
May 24th, 2006, 01:59 AM
Thanks for fixing the photo links, it's nice to be able to see the construction details. You appear to be using a large granulated burst such as polverone or granulated KP, the same burst for both the cylinder shell and the 6" ball? I see a bit of flash added at the core of the 6" ball?

The spiking pattern on the cylinder is interesting. It appears to be centered just to one side of the time fuse rather than going equally on all sides of the fuse. I will try to dig out some pics of the pattern we use, though it may be better suited to the 3/8" time fuse or 1/2" OD spolettes we use. 1/4" timer is a bitch to string around, too delicate.

How strong is that string? Can you easily break it with your hands?

al93535
May 24th, 2006, 03:29 AM
I am using BP coated rice crispies on all my shells. Yes I added 1 gram of 70/30 flash to the ball shell. I do not add any booster to the can shells because I do not want to damage the inserts, or thier fuses.

I am on the hunt for a good spiking string as this stuff is ok, but not that strong. I can break it with my hands, and I have broken it twice trying to spike the can.

I do not follow any real pattern for spiking. I just try to make it even, and eyeball it.

But I do now paste better thanks to your tips you gave me last year! :)

Bert check your PM's please.

Bert
May 25th, 2006, 12:04 AM
Here is a picture of a stringing pattern used on nominal 3" salute inserts.

You will note the use of two strands of string laid on together, a quick remedy for somewhat weaker than optimum string...

Bert
June 22nd, 2006, 08:18 PM
God help you, I think I hear the nbk2000 coming. After it gouges out your eyes and skullfucks you for your kewlness and lack of spelling skills, it will likely ban you.

nbk2000
June 23rd, 2006, 11:22 AM
They say there are only two certainties in life:

1) Death

2) Taxes

So now that I'm here, you got my money ready? ;)

al93535
August 17th, 2006, 03:07 AM
Well, it has been a bit of time since my last post. Lately I have been really into rockets. They are so much fun! These are all 1 lb rockets.

Here is my first 1 lb rocket with a header. It has a can and a ball shell atop the cored BP rocket.

http://www.apcforum.net/files/1lbdoublehead.wmv

The motor weighed 84 grams, and the head 240. With stick and everything the total weight is 336 grams.


Here is another whistle insert rocket, I love that effect! It is a 1lb rocket, 10 Ti whistle inserts and a ring of ruby red stars with a silver streamer in the middle.

http://www.apcforum.net/files/10tiwhistles.wmv


This is a 1 lb rocket, with my silver streamers I made up.

http://www.apcforum.net/files/silver.wmv


1 lb rocket, ruby red and my very own formula "al's silver streamer"

Video: http://www.apcforum.net/files/rubyredalssilver.wmv


1 lb black powder rocket with a whistle attached to the side. Red Mg/AP strobes.

http://www.apcforum.net/files/1lbredstrobes.wmv


And a Strontium nitrate and -325 mesh mgal rocket based on 1 lb tooling:

http://www.apcforum.net/files/1lbsrnno3n2mgal1.wmv

Here are a few pics of all the rockets:

http://img.photobucket.com/albums/v242/al93535/1lbwhistles.jpg

http://img.photobucket.com/albums/v242/al93535/2rockets.jpg

http://img.photobucket.com/albums/v242/al93535/doublebreak.jpg

http://img.photobucket.com/albums/v242/al93535/1lbtigertail.jpg



More to come soon!

c.Tech
August 17th, 2006, 07:16 AM
Ill like to say, good job, I’m impressed.

I especially like the silver streamer. The last one made me giggle :D, no offence, did it go twice as high as the rest?

How much did they roughly cost you?

I’m looking forward to the more to come.

Bert
August 17th, 2006, 09:59 AM
Hmm. Were you in Appleton last week, al93535?

al93535
August 17th, 2006, 06:33 PM
C tech: I like that silver streamer myself! I tried a few and never really got a good tail so I had to devise my own formula. I think it turned out nice.

The last rocket, the Strontium nitrate/MgAl rocket did go alot higher. In fact, it reached an altitude of about 1450 feet!

As for cost, I would estimate about 2$ per engine, and about 1-2$ per header. those are just estimates. I get ripped off on KNO3 though. I also just recently bought commercially rolled rocket tubes, which increased the price. But I was getting tired of rolling massive rocket tubes. The tubes cost me about 1$ each.


Bert: No I was not at PGI, although I am sure it would have been very fun! Did you go? I am not a member of any pyro club yet. I am planning on joining the WPA soon and attending WWB and Do-It.

Bert
August 17th, 2006, 09:06 PM
Yes. I was there for 9 days, we did the final show on Monday night. You would have been in heaven on the rocket line. I saw up to 6lb. whistle and strobe rockets being fired from about 100' away. Only one CATO'd while I was standing that close... The rocket guys set up a large tent and filled it with their presses and gear, building motors and trotting them out to the line for hours on end all week long. The FAA would probably not have been happy if they knew how high some of the launches went.

mash uk
September 17th, 2006, 10:39 AM
http://www.geocities.com/mashpyro/movies.html

I have a nice collection of "proper" pyro for your entertainment.

If its out of bandwitch just post here i can upload to photobucket.

grimreaper
January 8th, 2007, 08:18 PM
A cheap source of magnesium is the crankcases of the old volkswagen beetle , im not sure of the % magnesium, but sufficient to say it does burn very well, these crankcases crack and the head studs pull out after extended use and become useless for their original purpose, so should be available at scrap yards, milled to a fine swarf they make excellent sparkley stuff

related subject
I have seen in various threads and categories references to "washers" to reduce blowby on gas propelled projectiles , the piston seals sometimes called packings that are used in 99% of all pneumatic cylinders are available in a huge range of sizes and are very cheap , hardwood or uhmw projectiles or shaped as a cup to carry other projectiles can be suitably shaped in the simplest of lathes and when fitted with one of these packings produce a 100% gas tight seal ,be warned IN A SMOOTH BORE there will be NO blowby
this will increase chamber pressure and range
TIP
do not make the "fit" too tight the very edge of the packing just has to kiss the bore , the pressure does the rest, the higher the pressure the more the seal expands

brother john
February 19th, 2007, 03:07 AM
I've made about a hundred or so canister shells. They were mostly 3 1/2" with a few 5 1/2". The cans are cut from the tube that carpet comes on. The end-caps are made from scrap flooring which is 1/4" MDF board with a wood-like picture on it. Also I've used 1/4" MDF scrap from a friend's cabinet shop. I made a cutter for doing the end-caps on a drill press.The edge comes out with a step on it so the cap goes only part way in the can. So far all the spiking has been done with 3-strand jute twine except on the 5 1/2" shells. On those I use 4-strand jute. I hope to use linen twine on the next shells as it should make a harder break. Also, it might hold the ends in well enough to break the sides out good if I don't horizontal spike. I don't think I've had anything but bow-tie breaks & an occasional hose break. The carpet tube doesn't break too well for me with horizontal spiking. However, until recently I didn't realize that I could expect a more symmetrical break.
I've only used black powder coated onto 1/8" corn cob from the pet store. It breaks the 3 1/2's quite well. Some spread out to 300' or so.
I just had a friend tell me that she got most of what we shot on New Year's eve '07 on video so if we can figure out how there will be some pictures here soon. A lot of stars grounded-out due to a lack of elevation but still they were pretty. I changed from a 3 1/2" to 4" mortar without leaving enough time to experiment. Last 4th a shell blew up & I decided a little more clearance was in order. I was ill & couldn't go outside for a while so it was a last-minute change. I wasn't too sure for a bit if we were going to even get it together for New Year's. I hate it when that happens. I'll expand on this stuff next post. Good Night.

Bert
February 19th, 2007, 10:59 AM
A finished shell for a 4" ID mortar should be arround 3.75". That allows enough clearance for the leader and enough gas blow-by to keep the pressure down to safe levels, assuming you've got powder in the correct granulation (I'd use nothing finer than 3FA or 1FG).

Heavy cardboard tube of the type you describe should be reserved for salutes and such shells as parachutes and air mines where an end break is desired. The 1/4" flooring board end discs were what I did before I had access to purpose made discs. They worked fine, but make for some heavy fallout! Send an email to Tom at custompaperprod@wmconnect.com if you'd like to spend more time making shells and less doing wood working.

If you take a 1' length of 3" ID PVC pipe and wrap four turns of dry grocery bag paper around it, just gluing the last edge you will have a more suitable star shell caseing for a 4" gun. Make it long enough to pleat about 1" or a bit more down over your end discs. After loading and closing the other end, put another disc over each end and string with 16 turns end to end and sufficient turns horizontal to make squares. Paste with 4 more turns of the same paper-

What books or other sources did you use to arrive at your cylinder shell technique? Weingart's Pyrotechnics?

brother john
February 23rd, 2007, 03:52 AM
I have 1/4" -3/8" clearance now. I was using 3 1/2" Sch. 40 pipe which the shell would just barely slide down. Using 15 grams of lift powder was plenty for all the elevation needed for that size shell in that bore. I now am using 4" sch.40 pipe with a liner made of a piece of 4" thin-wall drain field pipe with a slice cut out so it could be squeezed down slightly to fit. Now it needs 30 grams to reach a decent height. The powder is fairly coarse, going through a 10-mesh screen but not through a window screen.

The shell that I had blow up had Veline stars with BP break powder. The time-fuse lit but the lift didn't. When it finally went it wasn't even a little bit of a flowerpot. Just one helluva bang & not much of a flash. It was around 11 PM shooting over a lake. All kinds of bullfrogs started croaking & some deer out in the woods started snorting. The mortar, a 24" piece of 3 1/2" pipe, was welded onto a 1/4" steel plate. It still is but the bottom got bulged out about a 1/4". I miked the pipe & it's still nominal size.

We were set-up on the end of a dock. The mortars were set on a cushion of wood chips from the pole mill & tires with the sidewalls cut out were set over each one up to one tire from the top. This area was then filled with chips. Not nearly as confining as burying in the ground but the best I could figure out for on the end of a dock. I am left wondering how much of a containment that actually is. No shells were salutes, on purpose at least. Anyhow, the mortar didn't go through the dock so at least the cushion was sufficient. Some HDPE mortars are really the answer though. Very little concern about shrapnel with them. They're high on my gotta get 'em list.

I came up with the carpet tube technique as a progressing from film canister shells more than anything I guess. Bigger is better! A lot of sites on the Internet also were an influence. I didn't find much at all on bigger shells but a picture or two. I was surprised to find the casings can be a fair amount less strong & actually be better for most purposes. The main drawback I've found with the carpet tube is finding a size to fit a standard bore.

krackerjack9
February 23rd, 2007, 07:43 AM
Your worried about shrapnel from a HDPE?? But your using steel pipe now??
And your shells are tight fitting in the Mortar tube?? Try doing a bit more research on the obvious

Bert
February 23rd, 2007, 11:45 AM
Brother John, PM me.

PVC is a poor choice. I know, I've gone through the same progression as you are now. HDPE, fiberglass or even heavy spiral wound paper are the proper things. We use schedule 40 steel tubes with welded in plugs as well, but only for cylinder shells more than twice as tall as their bore diameter.

Making star shell cases from 70 or 80 lb. kraft paper wound on a former frees you to make them to fit your need, rather than forcing you to make do with whar's in the dumpster.

You need to see the Fulcanelli articles in Pyrotechnica IX and XI just for a start.

al93535
April 10th, 2007, 09:49 PM
I have made a few new items and have some video for you all to enjoy.

Here are some rockets and shells.

http://www.littlerockauctions101.com/alpyro/saluterocket.wmv

http://www.littlerockauctions101.com/alpyro/beraqrocket.wmv

http://www.littlerockauctions101.com/alpyro/4inchmulticolor.wmv

http://www.littlerockauctions101.com/alpyro/4inchstreamertocolor.wmv

http://www.littlerockauctions101.com/alpyro/whistleredcrackle.wmv

http://www.littlerockauctions101.com/alpyro/win22.wmv

http://www.littlerockauctions101.com/alpyro/4inchcanberaq.wmv

I only wish I would have waited until it got a little bit darker before shooting. You cannot see the Ti in the salute. But, all in all it was a great time.