Aerial Shells

[Pretty green flame]

Rooster: Smart idea! But I think it will handle the lift now as the shell is dry!

Pretty green flame: Yes, it's a spollette. But the powder is not rammed that hard, instead I made a slurry with ~3% dextrin and gently pressed it. Now it's rock hard. Hopefully it will work fairly well...

For future shells, make a thick walled tube and ram the BP in really hard.

I have used cast spollettes in the past but have gotten a few missfires from them, rammed spollettes work everytime.

 

Just make sure your spollettes are 100% dry. If they're driven in they might cause some problems.

[AVR]

Holy shit!

 

I shot the 70g shell. It worked good, but the timing was a bit off... I am sure it exploded on the way down.

But I have learned one lesson: Never put stars in the lift-mix! Stupid me thinking the shell exploded in the mortar! It was hard taping it too since my camera is bad in darkness.

The break was ok, I think... but my four insert salutes all went of with the break(my ears are ringing). Note to self: Harder casings for insert shells next time and maybe some ear protection.

My second shell have to wait since it's allmost 11 o clock and time for beer and music...

 

I'll see if I can get anything useful from my DV.

[ULTRABUF]

I know PVC is a poor choice for using as mortars, but my friends found me some PVC that I believe could handle the force of the lift launching the shell out. My dad told me that normal PVC is schedule 40 or something like that, and this stuff is schedule 80. Its 3 inch ID, it has 5/16 inch thick walls, and it looks like it could take a beating. Whenever I get around to making my first shells, I am currently planning on using this as the mortar, however, I would appreciate any input anyone has on this find.

[justanotherpyro]

The debate with using PVC is this : If you have access to a better mortar like HDPE, paper, fiberglass or possibly steel( over kill for 3" shells ) then use it. If not, be very safe with PVC, and don't underestimate the shrapenel it can give off if there is a malfunction.

[Kilo_G]

I don't understand what people don't understand about NOT using PVC. They think "Wow, now I have a FREE mortar, that's like 20 bazillion times better than paying $10 for a real one."

 

Bullshit it is. Spend $10 or $20 and get a real mortar, PERIOD.

 

There are plenty of websites, such as www.pyrogear.net , that offer plugged HDPE mortars for short money. You can even find them on eBay sometimes.

[aquaman]

I believe that if you're using PVC as a mortar to put it in a bucket about the same size as the pipe and then fill around the pipe sand. I would think if something went wrong that the sand would slow the shrapenel down enough to not worry about the shrapenel as much. Wait better yet why not just burry the mortar in the ground?

 

How long do HDPE mortars last? I know that PVC wears away over time.

[Kilo_G]

How long do HDPE mortars last?

With out placing shells upside down in them and with howmuch most anyone on this site would use them...... most likely longer than you.

[aquaman]

Wow that long I was thinking a couple months, maybe a year. But years? That's amazing. I probably will order some off the internet some time soon.

 

How large in ID can HDPE pipes go?-just curious.

[Kilo_G]

I believe you can get up to 16", which is the largest readily available commercial shells that are launched.

[Mumbles]

You can get larger pipes specially made too, as well as odd sizes. I've heard of 7" shells, and 14" shells, which are not normal sizes. I don't know what they were shot out of. Well, the 7" was shot out of an old air tank with the top cut off, but the 14" I have no clue.

[Kilo_G]

I have seen a 20+ year old (possibly older than 30) 14" shell launched. Because they didn't have a 14" gun, they upsized the shell (to 16"). Upsizing shells is not something anyone shooting shells should partake in unless they have been properly shown/trained how to and even then it can be unsafe.

 

It was an unbelieveable shell by the way, all chlorate stars I believe, beautiful.

[ULTRABUF]

The only reason I asked about this piece of pvc is because its not just normal crap pvc from home depot it was found at a castings factory, and because of its labelling I've got a feeling that its got to be twice as strong as normal pvc, and the walls are nearly 3/8 of an inch thick. Thats got to count for something. Plus, if I buried theres no way I can see that thing cracking and sending shrapnel of any kind. It seems to be some pretty heavy duty shit, and plus I got it for free.

[Mumbles]

Brittleness does not change with thickness. All it means is that the shrapnel will be heavier and fly farther. Anything bigger than 2" of PVC is not safe reguardless of the schedule. I've had PVC take two 5g flash breaks and be fine, and some crack/blow up just from lift. It's touchy.

 

Also, free does not make it better. It may actually be worse. You don't know if it had some sort of defect, something was spilled on it, and thus the reason it was thrown out, or if it was just excess.

 

Needless to say, I HIGHLY recomend not using it, but I can't stop you. If in your newbness, decide to go ahead and use it, please be careful. I wouldn't trust any sort of PVC mortar unless the top was at least 6" underground.

[ULTRABUF]

Okay, I shall submit to your superior experience Mumbles. I was just really hoping that type of pvc would work well, it seemed like the solution to the pvc weakness problem . Thanks for the advice everyone.

[Mumbles]

Also, just since it seems you want to keep this low budget, try cardboard shipping tubes. I've used them with good success before. I was shooting from a bucket full of clay due to it being winter and the ground frozen. I added some clay to the bottom to give it some stability, and to keep the plastic endplug from melting.

 

I had use a 4" cardboard tube for some 4" spherical shells. I found out just how powerful my lift is. There was no bottom on the tube, just a tube in clay. After launch(and it launched just fine), the whole thing lit up(white bucket), a good 10 pounds of clay shot up out of the bucket, and the whole thing tipped over. The clay was smoking afterwards from the lift gases.

[Frozentech]

Well since there isn't a thread specific to starmines, I'll post it here

 

Here's a short video of a 4 inch mine shell I just shot. It had 50 grams of Winokur 12 glitter stars ( a mishmash of 3/8 and 1/2" pumped ) and 50 grams of mixed Veline orange and purple stars.

[edit] it used 20 grams of homemade lift.

 

http://i1.zvhost.com/1/a/au05n51g.jpg

 

I also shot a 3" can shell of hummer inserts, first time building a shell with inserts, and results were mixed. As far as I could tell from the video only 7 inserts 'hummed' the rest went off like weak BP salutes, not impressive at all. The rising comet of Win 12 glitter was nice tho I won't bother with that video unless someone requests it. I think hummers can be much improved with some metal in the comp for more visible pinwheeling, and I need to slow the comp down.

[al93535]

Very nice mine! Excellent lift, and they all burned out perfectly! I would like to see the hummer video too though! Good work!

[Frozentech]

Very nice mine! Excellent lift, and they all burned out perfectly! I would like to see the hummer video too though! Good work!

Thanks!

 

Here is the video of the 3 inch shell with hummers... If I can get a few bugs worked out ( slow the comp down a fraction, add something for tails ) should be an amusing shell. I will try again soon, and make it a 4" shell instead, can fit so many more inserts in that size.

 

I had actually forgotten I put a 3/4" pumped star of Win 12 on top of the can, and when I saw it I thought it was a malfunction ! LOL... I really need to stop babbling a 'stream of consciousness' monologue while I am filming pyro.

 

http://i1.zvhost.com/1/w/w2h5q6ts.jpg

[Chris]

Now I'm just pissed! Yesterday, after a long brake I had the opportunity shoot a shell. I decided to go with one of my 3inch red Chrysanthemums that had been stting in my lab for a while. I also decided to tape it for later analysis. The shell worked well and it was absolutely nice. Probably one of the best I've ever made for that matter. However, my cam just wasn't in the mood for co-operatting, and what I am left with is a slurry video that does no justice to the shell. I probably should have used manual focus and some other fancy night-features on the cam. Anyway, I'm going to post the clip to se for yourself;

 

 

Blurred 3inch

[Givat]

Amazing...=]

 

Say, what is the comp for "red Chrysanthemums"?

[psymon]

I am having problems with making my stars ignite in a shell.

It is:

 

45 Kno3

40 Aluminium 200 mesh

10 Sluphur

5 Black powder meal (Willow)

5 Dextrin

 

I wet them and pump them into small cylinders maybe 1 cm each. After a week of drying when they are rock hard i use them.

They are really hard to light in a shell. I use a 35mm film cannister and fill it with 1/3rd willow black powder plus 4/5 stars. When I sent the shell up none of the stars ignited. Will I have to prime them all with BP? Also I have tried making an insert of a small BP firecracker. it was about 2cm long with a visco fuse buried in the black powder. When the shell was fired it exploded fine but never ignited the cracker inside. Why is this? Commercial shells manage it, what am I doing wrong?

[Frozentech]

I am having problems with making my stars ignite in a shell.

It is:

 

45 Kno3

40 Aluminium 200 mesh

10 Sluphur

5 Black powder meal (Willow)

5 Dextrin

 

I wet them and pump them into small cylinders maybe 1 cm each. After a week of drying when they are rock hard i use them.

They are really hard to light in a shell. I use a 35mm film cannister and fill it with 1/3rd willow black powder plus 4/5 stars. When I sent the shell up none of the stars ignited. Will I have to prime them all with BP? Also I have tried making an insert of a small BP firecracker. it was about 2cm long with a visco fuse buried in the black powder. When the shell was fired it exploded fine but never ignited the cracker inside. Why is this? Commercial shells manage it, what am I doing wrong?

The only stars I don't prime are those that are high in charcoal. You should try priming those by lightly spritzing them with some 25/75 alcohol/water and dredging them in meal powder. If a star won't light in a star gun ( you are testing them ?) or by a quick pass with a torch lighter they generally won't have 100% take fire in a shell without priming.

 

Visco fused inserts definitely require priming on the fuse. Try using a razor blade to slightly split the end and dip it into a slurry of BP meal and Dextrin to form a matchhead sized blob on the tip of the fuse. It' will light in any reasonable break charge.

[psymon]

Thanks for that I have some stars coated and drying out as we speak...

Just one other thing. I like to use 35mm film canisters as shells a lot because I get a constant supply from a local photo lab (about 40 a week). I use hot glue to seal the cap on plus some more around the rim. I then put cloth sticky tape around the shell to spike it.

I fire the shells and they make a nice loud pop/bang.

When I examine the shell case after firing it tends to just blow the base off the film can. Is there any way I can make the shell burst and make a more symetrical break?

[TheSidewinder]

If you're blowing off the *BASE* of the film can, I believe the answer is "more spiking".

 

Personally, I'd double the amount of filament tape going over the end of the can for starters. (Or switch to hemp/flax twine and spike and paste just like a bigger shell.) Experiment a bit.

 

M

[psymon]

Ok will do. When my stars dry out fully I will do my best to get a video of it. My camera only does Silent .MOV (apple quicktime) so the vid maybe a bit big... (2.5Mb Max)