Insert Breaks

[Bcorso85]

Hey guys,

I'm making my first cake. Its approx 400 grams or so. I have my tubes rolled and glues together, and my insert tubes rolled and unsealed. This is a 12 shot repeater. I was wondering if anyone has any advice on breaking these 12 inserts. They are about 4 inches tall, but remember they havent been folded at the top or plugged yet. I expect to put a bp/ Ti tail that acts as my timing and ignites a 1/2 inch of paper fuse into the small cannister. about 2-3 seconds delay...to give you an idea of how much space for stars and burst charge is left. I made some h3 scratched together and lit it uncontained. It was very gassious, but slow as far as I was concerned. I tried 50 p. nitrate to 30 sulfur to 20 dark aluminum. Very slow uncontained and free flowing. Was actually pathetic. as far as i know my chemicals are pretty pure. I am not sure, however of the chlorate. any suggestions? There will be sizzling green stars (Emerald Green + coarse magnalium). So they can with stand a decent break. I do want a large spread on the break.

 

Any help would be appreciated.

Thanks

Ben

[Col]

If the insert cases have a strong thin wall you wont need much, You do need a clay bulkhead above the tail comp for confinement, as once the tail is gone you`ll be left with an open ended tube.

These 5/8" id x 2" inserts break over 30ft wide with a teaspoon of 2Fg bp and 0.3g of whistle. The cases (0.5mm wall) are made from 30lb virgin kraft/pva, the tail comp and clay bulkhead (4mm thick) are pressed in at 4500psi using a support sleeve.

Edited November 14, 2012 by Col

[dan999ification]

for 40 mm ( 4 inch tall )bombettes with 2mm walls, made from 200 gsm recycled card, ive used bp,1,2 and 3 grams of gd/al and bright flake perc 70/30, my breaks are not as big as cols but the inserts are made differently.

Rammed cat litter with visco delay, veline star comp with ti made as slurry and poured over the clay ( after a thin layer of hot glue to stop the solvent attacking the clay) imho you can use more than 3g of most flash, its all in the priming.

I was tempted to fill the last few inserts with f and stars on my last cake, im sure the stars would light, nice finale if they dont.

The walls must break before the plugs otherwise you get very wide sparse breaks.

Test a few before you build it.

 

Dan.

Edited November 14, 2012 by dan999ification

[Col]

I use captive visco in clay plugs as well, mostly depends on what it needs to do. Sneaking up a batch of salutes without tails to advertise their presence is a good one

Ben didnt mention the insert diameter but it sounds like they`re at least an inch if they`re >3" tall. I use 5g of slow flash (5/3/2 dark flake) for 28mm id. The trick as Dan says is to make the walls strong enough to survive the lift but thin enough to give way before the end plugs. I always try to minimise the clay plug thickness, not only to save weight but also because if (when) the bottom blows out first they can travel at high speed in any direction.

 

Captive visco in clay plugs, recessed and flush.

[AlexPyro66]

You can use granulated whistle mix

[psyco_1322]

Yeah I'd start with using about 60% volume of stars and the remaining with loose granulated whistle. Be sure it mixed up though. It might still need the "bulk head".

[Bcorso85]

Hey guys. The inserts are 1 inch in diamter, and 1cm-2cm thick. The paper is builders paper bought from home depot. It is alittle ligther then the paper you would buy from rolling thunder pyro. It is cheap and abundant, so for $10 it is worth a try. If i were to break with bp, is it better to use some meal fresh out of the mill, or lightly granulate it?

 

I have done a few tests. One turned into a salute. The slow flash inserts were very weak. I could compare it to a very cheap rocket with a small payload. The insert then jetted around like a go getter. I have sacraficed the tail and rammed the clay at the bottom of the inserts and drilled a small hole for the visco. I will try the whistle mix and bp, aswell as just alittle flash. I dont know why but i can't make a strong slow flash!

 

 

Thanks again guys I guess i need a little more trial and error.

Ben

Edited November 16, 2012 by Bcorso85

[dan999ification]

if you use bp you must granulate it and it must be good quality, even col boosts his, i would use 2mm/10-16# and have but prefer to use 70/30 perc/gdal, i find it simpler to fill them half with stars add the flash and then fill with stars, disc, glue done.

There is no need to drill a hole in the plug, take a 1 inch dowel cut two pieces, drill a hole in the centr of both ( the same size or a little bigger than your fuse ) voila plug tooling. You'll need to adjust the height of the rammer and base aswell as the depth of the hole and length of fuse to suit your needs.

I have had the same problems with these, mg/al f made salutes, slow f with bright flake made spinners, just dumped a poof out of one end or when they did function the spread was poor, the confinement is important using slow flash and unless very thick or pressed plugs are used its impossible for me to get consistant results with it.

For such a simple construction these have a huge amount of variables.

 

Dan.

[Bcorso85]

Yes i cant believe all the variables involved. Building shells is actually a lot easier im noticing.

Well if you guys dont mind I'd like to run down what my insert will look like. Just so I dont make any huge flaws aside from tweaking it.

 

From the top,

 

I have a Clay plug

Then My stars mixed,

In the middle is a break charge,

And at the bottom of this chamber is a second mix of stars.

This is resting on a plug with a hole drilled in it, and a piece of paper fuse running to the center of the chamber.

 

Alittle bit of the paper fuse is sticking out, mixed into the top of a nitrocellulose slurry with my b.p. TI mix acting as my timing.

The streamer dies out and hits my quick match.

 

Will this slurry work well enough so I dont keep tearing my tubes when I ram my clay and streamer comp?

[Col]

It would be better for consistancy if you start with a recessed clay plug with either captive visco or a passfire hole. That would save you a lot of time drilling holes for fuse or worrying about locating the fuse disc (on top of the already loaded stars/burst) so it leaves exactly the same space for the streamer comp for every insert.

 

Some simple tooling will make the job easier, Alll you need is a piece of wood for a base, epoxy a section of 1" dowel (the depth of the streamer comp) onto the base and drill a 2.5mm hole in the middle (this holds the visco).

Take another piece of 1" dowel an inch or so longer than your case and drill a 4mm hole right through the middle. Use a 1/8" plastic drinking straw in this hole to guide the visco into the hollow rammer.

Locate the straw over the visco, pour in the clay and feed the hollow rammer onto the straw. Compress the clay with hand pressure while gently twisting the straw out of the rammer. The idea is to get the clay to grab the visco, not trap the straw in the clay or have the straw pull the visco out with it. Once you`ve removed the straw you can fully consolidate the clay with the mallet.

Here`s my simple insert tooling made from 28mm hardwood dowel (ex-curtain pole), this is for recessed clay plug and captive visco.

A: Base for 4 different tail comp depths (6mm-24mm), the steel washer spreads the load.

B: Clay plug rammer with 4mm thru hole for the straw, (doubles as an internal support when pressing in the tail comp),

C: Tail comp rammer (also with 4mm hole for the straw)

D: Case extender for tail comp. (comp needs more tube space prior to pressing)

Edited November 17, 2012 by Col

[Col]

I figured i might as well show you the 5/8" tooling while i`m at it. Its double duty for both comet bomb (tail comp as time fuse) and captive visco inserts.

Key to the 1st pic in the group,

A: Chunk of 1" aluminium T6 rod with a hole for the visco.

B: Support sleeve, 17mm id (not split),

C: Hollow rammer, 1/4" thru hole with a length of 1/4" od (white) ldpe tube in it.

D: 5/32" ldpe tube (black) which is a sliding fit in the white ldpe tube.

The 1" base and support sleeve are wrapped with kraftpaper/pva just to bring the diameters up so they fit together. The rest of the pics illustrate the steps for a captive visco insert which is very similar to the 28mm tooling steps.

 

The final pic shows a 1/4" brass rod that replaces the white ldpe tube in the hollow rammer for making comet bomb style inserts, the tapered end of the rod extends 4mm beyond the rammer when the top is flush.

I dont use the 1" base for comet bomb inserts, just a piece of masking tape to seal the bottom of the support sleeve. A 5/8" solid aluminium rammer (not shown in the pics) is used to press the tail comp in place first at 4500psi.

The brass rod is inserted into the hollow rammer and both are pushed into the tube so the tapered end of the brass rod is resting against the pressed tail comp. Then you gently lift the rammer (leaving the brass rod behind) until the rammer clears the tube by an inch or so and you can grab the brass rod so it doesnt move. If it shifts, the clay will find its way underneath it and your passfire hole will be fubar

 

A pre-measured amount of clay is dropped into the tube (with the brass rod still in place) and the rammer is carefully pushed back down over the rod and pressed to 4500psi. The brass rod is captured by the clay as its compressed but releases very easily with a twist. The result is a tapered passfire hole in the 4mm thick clay bulkhead. Pics of both types of inserts made with the tooling are in the thread.

Edited November 17, 2012 by Col

[Bcorso85]

Thanks Col,

as soon as you posted I went and made my own little tool set for the inserts. Thanks alot. I made a few inserts and they look fantastic. They are much easier to make. I havent tried any yet, but I hope they function as well as they look. The only Issue I see is that end plug on top. For now, until I order some 1 inch end plugs to glue in, I'm cutting a piece of my dowel off and glueing it in. Other than that I just have to dial it in. I really appreciate it.

Ben

[californiapyro]

Ben,

What I do for insert tops, is I cut out a piece of cardboard or two to put in the top. I insert the cardboard, then cover in 1/2" or so of hot glue. Cheaper than dowel and works well

 

-Hunter

[Col]

The cheapest option is to find a piece of steel tube with an id the same size as the end caps. Grind the outside edge down at 45degrees so its sharp and you`ve got yourself a cheap punch. I cut ring binder folder covers into strips and punch half a dozen discs at a time using the press. The tube in the pic is 19mm od x 1.5mm wall stainless steel. I`m so thrifty i begrudge breathing out

Edited November 20, 2012 by Col

[Bcorso85]

Excellent ideas guys. Cant wait to post the cake. I expect to try atleast 6 shots on the 27th (my birthday ) along with 2 Four inch rounds. One is a Green Willow and the other is alittle differnt. Single petal shell, with laquer red stars, then willow stars lined against the reds, hopefully making the illusion of a willow shell out of nowhere. Ill post the videos on this topic Edited November 20, 2012 by Bcorso85