Aerial Shells

[Frozentech]

Most stuff you read says you shouldn't use KP in smaller than 3" or 4". I think it's hogwash (LOL I said hogwash). I've seen shells using KP burst and they work fine (all the way down to 1 5/8"). The key is properly gluing the shell. Also dusting all the stars with meal or granulated KP is important. You also need to use whistle or flash inconjunction with the KP if you're using KP on ricehulls for a break.

 

If you have a passfire subscription Lloyd has an excellent article this month on 4" plastic shell construction, which looks to be a much faster/easier/better working way to construct plastic shells.

I have Passfire, I love that article. I am planning to switch from now on ! Much cleaner and easier method, why didn't I do it that way before ! No more clapping the hemi's together.

[bubbelpower]

How many times should i paste a 2",3"and 4" shells, if I use the thin Kraft-paper?

[Mumbles]

"thin" kraft paper is not descriptive enough, you would need to give a weight. Anyway, it depends on too many things to give a definate answer mainly strength, paper type, and thickness.

 

For the purposes of this, I am going to assume roughly 35 or 40#, and that it is recycled. These values are just some quick calculations based on a passfire article.

 

2" - 7 layers

3" - 12 layers

4" - 17 layers

[bubbelpower]

Its 40#, if that helps.

But thx anyway.

I think i've been pasting my shells not enough, ive just pasted 4 layers of 40# kraft on my 2" and 8 layers on the 3" ones.

 

BTW how do i form a "Saturn ring"?

[Chris]

You can either wrap the ring stars in tissue forming a long 'line' and then align it with the inner circumference of the shell. Alternatively you can hot glue the stars to the shell forming a ring.

[Givat]

Pasting is just irritating, especially when you make couple of shells.

 

Any one ever thought to spike round shell?

[bubbelpower]

Dont you think it would hard to spike a spherical shell?

[Givat]

It will be harder, but if you use enogh force the string will wrinkle a little the paper hemi and wont slip. I guess you can do only vertical spiking but this will sure can work good.

[bubbelpower]

I still think its easier to paste spherical shells than spiking them.

 

BTW how high should shells go? My 2" go to about 70', and my 3' ones to about 120', as an estimate.

[Pyrohawk]

I have seen spiked spherical shells before. Whoever it was had spiked them but only in one direction. He had pasted a couple layers, spiked, then pasted another couple layers. It looked like a lot of effort to me.... I'll just stick to pasting personally...

[Kilo_G]

my 3' ones to about 120', as an estimate.

120'!? I'd say most 3" shells go 200' or more high.

[Frozentech]

I still think its easier to paste spherical shells than spiking them.

 

BTW how high should shells go?  My 2" go to about 70', and my 3' ones to about 120', as an estimate.

 

I want 200 feet for a 3" shell, but some references call for more :

 

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

 

Size Burst Height

(in) (ft)

 

3" - 400

4" - 500

5" - 600

6" - 700

8" - 900

10" - 1050

12" - 1150

 

The height above the ground for which a shell should typically break. Rule of thumb: 100ft plus 100ft for each inch of shell diameter.

 

Source: Illustrated Dictionary of Pyrotechnics

[Kilo_G]

3" shells that I have launched usually go between 250 and 350 feet. Height also depends on the type of stars you've got in them. If you've just got a fast burning peony shell then height isn't wicked important, though you also need to know roughly how big your spread is. If you've got a long lasting charcoal streamer type star then you obviously want the shell to go higher.

[bubbelpower]

I meant 170' and 220', i just typed wrong.

[Pretty green flame]

good day everyone, i thought i'd post a couple of pics of 2 2" canisters.

 

http://i15.photobucket.com/albums/a374/AVP...ersbymortar.jpg

http://i15.photobucket.com/albums/a374/AVP...chcanisters.jpg

 

Both are filled with white stars and BP covered grass seeds as the break charge. And they were spiked hard with hemp twine to ensure a good break, hopefully.

 

They are charged with 7grams of Alder BP and they weigh in at around 70grams each. Overall it should be good.

 

Oh yea, and the timing has been done with a 1/4" spolette which has been rammed to a depth of 2cm. Should give a delay of about 2-2.5sec.

[Rooster]

Sounds nice, PGF. Hard breaks are hard with those smaller shells, remember that if they break out on the side. Actually, why don't you scale up abit? You always make the small shells, when you are more than experienced enough to step up to at least 6" shells. Much more possibilities, more space, and easier, but takes more chems obviously.

[Pretty green flame]

Sounds nice, PGF. Hard breaks are hard with those smaller shells, remember that if they break out on the side. Actually, why don't you scale up abit? You always make the small shells, when you are more than experienced enough to step up to at least 6" shells. Much more possibilities, more space, and easier, but takes more chems obviously.

Yeah i was thinking about some bigger shells but the main problem i have is i can't get the right size mortar. I mostly make 2" shells becouse my father can get me some suitable paper tubes. And ordering HDPE from the US is kinda a problem. Either they don't ship out of the US or the shipping charge is quite high.

 

So basicly i CAN make bigger shells but i have no mortars to fire them out.

[Chris]

Most waterpipe companies sell HDPE. It might go under a different name though, like PE pipe or water pipe.

[Rooster]

4, 5, and 6" mortars are easy to find. At least steel ones. Go to a scrapyard, look for diving flasks, old gas tanks, piping, or whatever. You would do smart in burying the steel tube, though. It is really amazing what you find if you go to the right places with your eyes open(scrapyards, construction sites are good).

[Pretty green flame]

Most waterpipe companies sell HDPE. It might go under a different name though, like PE pipe or water pipe.

You just gave me an idea. Not far from me there's a large warehouse from a water company and IIRC i saw some HDPE piping there, might be worth to check out. But some of those come all rolled up. Rooster i belive you asked something about this type of pipe and how to make it straight. Did you find any solution to that.

[Kilo_G]

There's different types of HDPE pipe. The coiled up variety you are talking about is used generally in lawn sprinkler systems (and as an outer jacket on certain types of wire but that is a whole nother story) and is not really suitable for pyro. The type of HDPE you want is the following:

 

IPS 2" 160 PSI @ 73degree's F DR 11 ASTM-D-3035

 

This type of pipe is basically the same as PVC except better (cause it's made from HDPE). For some reason (mainly cause it's a bunch of political bullshit) this pipe isn't used in electrical work, even though it is better than PVC.

 

This type of pipe is generally used in things like sewer/hazardous material drainage. It is preitty rock solid and not flexible at all (like the stuff that comes in coils). The flexible stuff's wall is thinner.

[Rooster]

The coiled variety of HDPE pipe is more than thick enough for pyro use, but it is not easy to get uncoiled. The ones had, I "borrowed" from a construction site. They have been standing out in the cold all winter, but they are starting to straighten out. Not suitable for pyro use yet though. I think it will be too much work to make these coiled HDPE rolls work for mortars.

 

However. Have in mind this is Norway and not the US, but Kilo G, but if you were to find a way to straighten out this rolled up 2" HDPE pipe, it would be more than suitable enough for pyro. The walls are about 8mm thick, which will hold the pressure from most 2" shells, even if it were a heavy zinc-spreader multibreak shell (not that we see to many of those nowadays ) I have a little bit of the uncoiled variety too, it is EXACTLY the same, just not coiled.

 

In the US there is something called DR11 driscopipe, which may be the same as what Kilo is talking about.

[Pretty green flame]

Heheh, thanks for your answers guys but at the moment i am talking to the nice lady from kastner HDPE moratrs and she has agreed to send me some mortars. Gonna get some 3" and 4" for a start and at the same time i am going to order some plastic hemis from cannonfuse. Oh yeah, things have started to get good. Although i think i'm going to get a heart attack when i see the price quote, but no matter this is a once in every few years type of investment.

[Kilo_G]

HDPE mortar will, literally, last you a lifetime, except perhaps short of a 3" or 4" titanium flash salute being put in your mortar upsidedown. The only pain about mortars is cleaning them. I have literally wraped fuse around an HDPE mortar and put duct tape over it to see what damage it would do. Nothing, just some white marks from the fuse.

 

So, unless you destroy them, you'll never need to buy them again, unless you want more.

[bubbelpower]

I'va found a few 3" plastic pipes in a big garbage container, but i don't know which type of plastic they are. Its definitly not PVC, becayse Ac wont soften it at all. What types of plastic are pipes made of? And are they strong enough to be mortars?