Cakes

[Ventsi]

Ok, this has seriosly been pissing me off, especialy of recent times.

 

How the HELL are comercial cakes plugged? Not the bottom plug I know what that is , what do they use for the top plug on larger scale cakes? I'm talking 1/2 "- 1" , my shots never lift right, they barely pop out the tube, my small ones work great but I'm having some real trouble on larger scale stuff.

 

So pretty much I'd like to know how commercial cakes are top plugged.

[Piet]

You use something like this:

 

http://www.kukkobenelux.nl/turnus%20holpijpen%20ed.htm

 

Ram a lot off those out of cardboard and push 1 them with a rod into the tubes.

[TheSidewinder]

Piet is correct, it's usually a chipboard/cardboard/posterboard disk.

 

Here's some more info you might find useful:

 

For the very small-diameter cake tubes in commercial Class C cakes that *I've* seen, all of them are sort of like "mini-cannisters" in the manner they're loaded. If you haven't already, take one apart carefully sometime and note how they're made, and how they usually side-fuse everything to breech-fire each cake shot. Each tube's fusehole is often pointed in a specific direction to prevent a jet of flame from igniting the next row prematurely, and it's all covered with tape or similar.

 

Usually, a *very thin* cardboard disk that fits snugly is pushed down, and often PVA(?) glued, into the tube after loading, in order to keep the contents from spilling AND to keep the neighboring tube's launch from igniting it by falling debris.

 

They don't provide any containment though, they're just a barrier against spillage and cross-fire.

 

EDIT: Sorry, the "safety-conscious part" of me has to add this: In *small* cake tubes, they *might* be using a plug for some containment to make for a better lift of a light payload. At that scale, the pressures involved aren't a worry. But when you get to larger sizes you definitely don't want to do any "containment". I think you know why. The plug will be there only for the reasons I mentioned a few lines above.

 

Poor BP or too much tube clearance will cause the problem you described about "barely popping out of the tube".

 

If your shots aren't performing right when launched from a single "test" tube, without any top-plug, you need to work on them some more before trying to make a cake out of them.

 

The insert clearance is very important, as is the BP you use. You should have about 1/16 to 1/8 of an inch side-clearance for an insert, but you'll have to experiment a bit. As to BP, for tubes 1" or less I'd use 4Fa, and 2Fa (or 1Fa) for larger ones, if you can get commercial BP. If not, you have to be able to make some pretty good BP of your own. You want good hot BP, especially for the smaller tubes. And again, you'll have to dial that in yourself.

 

I assume you're breech-firing these, with some visco, just like the commercial ones? If so, make sure the side-hole you punch for the visco is just big enough to let you get the visco in without twisting or forcing it. Angle-cutting the end beforehand helps. Too large a hole will reduce lift, and increase the risk of crossfire.

 

Once you get single-shots to fire reliably, then start bundling them. You can learn a lot about good fusing by taking apart a commercial cake, as I said above. I did several times, and noticed that they took pains to cover everything with tape and pasted paper, which makes sense. Don't want all the tubes going off in a half-second.

 

From what I've heard, making *good* small cakes is somewhat of a black art.

 

Hope that helped.

[firetech]

I put a piston in all of my mines and/or cakes. It DRASTICALLY improves the height of my devices. To do this I simply glue 3 squares of kraft together with Elmers and poke a few holes with an awl to allow gasses to pass through. I also trim down the corners to make a rough octagon. Then, I i center the piece over a dowel or rammer that is lightly smaller than the size of the tube and press the edges down over it to form a cup. I push that down over the bp (make sure its snug against the sides of the tube) then put in the effect. It That might help to get your stuff in the air.

 

Now about the plugs.

I'd use the same method that I make the pistons with, but without the holes. It's pretty makeshift compared to the chipboard discs but I'm sure it'll work fine.

[Ventsi]

Interesting...

 

I see what you mean, for small stuff make a tiny casing , plug the top , insert stars, a thin barrier, lift, bottom plug, load in tube, visco , shot.

 

So its basicly like making super mini bag mines that are bottom fused, interesting never thought they'd do that for commercial...

 

The way i did it for a 1" tube was : pour in lift, put in a bunch of small stars , stuf in a wad of paper - didn't work.

 

I'll give this a go tonight and tell you how it goes.

 

EDIT: My 1.5 mines and up to 3" are totaly fine I use NightHawk's tut. and they work perfect every time. Its about time I upload my 3" monster.

Edited July 8, 2009 by Ventsi

[TheSidewinder]

Ventsi, I thought you were talking about cakes that use inserts which would go to height and then burst like a normal aerial shell, not "super mini-bag mines". (Though that's a darn good idea. And mixing them in one cake might be nice.)

 

Are you looking to do both?

[Ventsi]

No ,I'm looking for the Mini Bag-Mines effect, I've got one 1" test shot loaded and i'll shoot it tomorrow night, get to test out my KClO3/CaSO4/dextrin reds[pinks] too .

 

However my inserts are just fine , my 1'' shells burst a bit low but that can be fixed with a bit of Uncle Elmer around edges of the *shell*, or some more lift .

 

Were you talking about loading comets and other *one item per tube* stuff, I still need to test single shot comets.

[TheSidewinder]

OK, yeah, I was talking about actual inserts, like on...... oh, Fireworks Fiesta (very small shots). Or some of the larger diameter Black Cat cakes that are all Brocade or aerial shell shots. That sort of thing.

 

Looks like you're on the right track for the mine effects with the method Firetech posted.

[firetech]

But how do they make those tiny little shells?

[deadman]

Tiny little hands?

 

But seriously If I get entirely what you're talking about then you mean a 1 inch or smaller shell. I actually have done this using those commerical "crackle bombs". They are usually green hemis filled with dragon eggs. Using extra small stars and an extra hard break they make decent small shells. The fly very well out of a 1" ID mortar. Make sure the stars are well primed because there is such little surface area.

Edited July 8, 2009 by deadman

[TheSidewinder]

But how do they make those tiny little shells?

 

Well, not with tiny little hands.

 

In the Fireworks Fiesta cake, they're just smaller rolled tubes, about an inch or two long. One end is plugged with a clay mix of some sort. Then they put some burst charge in, a cardboard disk, then Microstars in some of them and (even tinier) firecrackers in others, then a top disk. Those are placed into the larger cake tubes

 

Take one apart some time. There's like 99 or 109 individual shot tubes.

 

I do this, and then use each assembled tube as a single-shot mortar for what I call "White Trash Fireworks":

 

Take a used Shogun "Sky Bomb" tube. Drill a 1/4" hole in the side, about a half-inch above the plastic base. (You'll have to do some measuring to determine the right heights involved.)

 

Drop one tube from the FF cake into it, lining up the FF tube's hole with the one you previously drilled.

 

Twist a piece of Visco into the FF cake tube, and light it. After the shot, remove the now-empy FF cake tube.

 

Repeat.

 

For $15.00 you get ~100 "mortars". Great entertainment for backyard shooting.

[Ventsi]

I was thinking bombettes, which wouold be very close to what you're talking about.

Basicly get a tube, plug it, fill with microstars and whistle/flash/ put in a fuse , cap it.

 

http://www.pyroguide.com/index.php?title=B...and_Comet_Bombs

[50AE]

Just a off-topic question...

 

How do you obtain a red color from KClO3/CaSO4/dextrin ?

For me it does a deep orange, but red ?

[Ventsi]

I lost my notes from making it .

Off the top of my head I think it was something along the lines of

6 KClO3

2 Dextrin

1 CaSO4

1 PVC

 

I used crushed up gypsum board BTW.

[50AE]

Well, my camera catches the color almost as I see it, and here is the result of a small pile burnt in the open :

 

http://img194.imageshack.us/img194/9840/mov045310001.th.jpg http://img399.imageshack.us/img399/7748/mov045310002.th.jpg http://img39.imageshack.us/img39/3346/mov045310003.th.jpg http://img190.imageshack.us/img190/9369/mov045310004.th.jpg

 

But I made some stars and I'll test them when they will be dry.

[Ventsi]

Well I just shot off the pink 1" mine, and it was ... wonderfull.

The method worked beatufly and shot the stars nice and high, 3g BP sent them a good 60ft.

The stars burned a brilliant and distinct pink ,no orange stuff here. Altough out of ~15 only 7 lit, so a sulfurless BP prime would be desirable.

 

50AE be my guest and try this with some gypsum board, I can't post or show a video of the stars burning since I can't find my camera's charger.

 

EDIT" The stars show no deteriation WSE , and aren't any more sensetive than in the first place, which was... none , they aren't shock sensitive .I'll keep the rest of the batch for another month and report again.

Edited July 21, 2009 by Ventsi

[hillbilly416]

Thanks for the good info.I enjoyed reading all the post.

[justanotherpyro]

For all of my star gun shots I load the Bp then star and then I use a wad of toilet paper and ram it down the tube on top of the star to give extra confinement. for smaller stars ( 3/8" 1/2" etc..) it works well and if you want to you can cover each mortar with a piece of aluminum foil as an extra precaution to prevent ignition from fallout.

[Ventsi]

Yeah thats what I used to do on my stuff 1/2 and under, but its really inconsistent and more time consuming.

I might throw up a blog or a tutorial on doing the mini bag mine method, I feel it would produce very consistent and reliable shots , and when mass producing its really easy to do.

[Mumbles]

A trick I used to use when making these small mines was to add the lift, then a comet, then some stars. The comet gave a good enough sabot to really get them up there. It's kind of cool when the stars burn out to leave the long comet trail too. I also use to add BP, then wadding (toliet paper usually), then the stars, then another wad of toliet paper. It makes kind of a mess in large cakes, but it worked well for single fire.