6 inch stars and shells

[TrueBluePyro]

Im not sure where to put this, but I'll put it here because I am a newbie at making 6" shells.

 

The effect I'm looking for is a red that has a silver streamer behind it.

 

This is my plan for it:

I have firesmiths 3/4" "multi use pump" which can make stars that have a "cavity" and that is meant so that you can press another star compostion in there.

 

I want to use the Ruby Red forumlua and for the silver I want to use a "parlon bound" comp.

 

For burst I will be using BP on cotton seed and a booster using slow flash.

 

My questions are:

• Is 3/4" to big for 6" shells
  
• How many wraps of gum tape is recommended
  
• I think a booster is recommended, so how much would you say?
  

I know the most I can do is test my self, which is what I do all the time, but this is a 6" shell and I thought it might pay to read as much as I can and get any advice that people could throw at me.

 

I'm sorry if I sound stupid, but I kinda want to get this right, in the end it could turn out to be a nice effect first time round...maybe,, will see.

 

 

Much appreciated,

TBP.

Edited January 3, 2010 by TrueBluePyro

[Arthur]

With space to put 180 - 200 stars in the shell yes I appreciate asking questions before committing to that much work for a test! 3/4 is a good start for a 6" shell. Go through all the compatibilities before you settle on comps.

[TheEskimo]

I have heard that you don't need a booster for shells 5inch and above. Just the total volume of the shell provides enough room for more than enough BP on a carrier. It also depends on what kind of break you're going for. I have never made one, personally, but I have read a bit about them. Pianomistro has a 6inch shell tut on pyroguide. That looks like a good one; it also just uses BP on carrier for burst, with just a bit of whistle for booster.

[Ventsi]

Are you sure you want to go through with all the labor of making cavity stars and then filling them? I recommend you just "splice" the two comps together by using the same binder and put two pre-rolled slabs of dough on top of each other and then proceed to cut. This method would give the effect of a silver/red star and assuming the red burns longer it should leave red stars towards the end.

 

If you still want to stick to the cavity comet stars{Which in the end would be much easier to arrange in the shell, and give a better looking break} I suggest you go with Hardt #3 Silver and Ruby Red. Both are super bright and should stand out well.

[Mumbles]

I would say 3/4" is a bit too big for a 6" shell. I generally use 1/2 to 5/8" cut stars. You have to remember that pumped stars will be longer than they are around, which may not leave enough room for your cotton seed burst. As someone else suggested, you may want to try something cheap and easily produced for your first few to get the hang of them. Cheap glitters like D1 or Win 20 are always nice.

 

The splicing idea probably isn't the best. The chances of getting your two compositions to stay together through drying, priming, and bursting seems rather low.

 

As far as booster, I can't help you. I don't use boosters, and don't use BP burst. As far as pasting I can be some more help. I use 15-19 layers of 35# pasting on my 6" shells. With some practice, you can do an entire shell in 30min or so. With a few cheap tools and stuff, like the sponge in the tupperware container, this can be cut to 20 minutes or so.

[TrueBluePyro]

Ok, thanks everyone for your comments. After some thought, I'm changing my plan. I will use a simple/cheap star Win 20 (is it alright to pump MgAl comps, I'm more of a fan of rolling stars so I wouldn't know) as this is my first large shell and I wouldnt want to waste anything as mumbles said.

 

I do have the sponge in the tupperware container system and its makes things very quick. I did a bit of reading on passfire and they have a article on "Gummed Tape Ball Shells" and they use a low number of layers and sub with slow booster, also saying that using 3 layers of 60lb gum tape will be enough.

 

How does that sound? Oh and also does the 1/10th lift ratio stil work for these large shells, im sure you could put less powder in, so something like 1/12th or even 1/16th...Im not sure, it would depend on my powder.

[Mumbles]

I always use 1/16th plus a bit of extra. It's hard to quantitate the extra, it's just by feel. 1/16th works fine with commercial 2FA. The same with 4FA is crazy. The shell was still going up fast after 5 seconds. It's better to be too high than too low. These shells are pretty heavy, so testers will use a lot of BP, and you'll have a 3lb projectile coming back to earth. 1/12th sounds good if you want to be on the side of caution. You can always lower it later if the shells go too high.

 

I'm not particularly fond of the method on passfire. I just don't like using that much flash with that kind of build up around the poles. It might be interesting to see what would happen with more traditional strip pasting, like I use the tape for. The shell is only as strong as the weakest spot, right? I think I said before I don't use BP to burst these shells, so that also prevents me from using this method.

[TrueBluePyro]

Yea, I will go for the 1/12th and tune it for next time.

 

Where I am kclo4 is unfairly expensive and so I would rather not use KP for burst while BP is very cheap for me. I will give passfire methods a go with a few more layers.

 

Anyway, it is coming together, I'm glad I asked some of these questions as I just made 500g of Win 20 which made 55 3/4" stars thats about halfway,, maybe.

 

Thanks mumbles.

 

Anymore advice would be appreciated.

[Updup]

In a shell of that size, you could put two layers of stars in right? To make up for a the space lost you can then just add a little bit more booster and you can keep a good break with alot of stars. And this can work for 4"+

 

Wouldn't this work? Or am I just insane here?

[Bonny]

how does that sound? Oh and also does the 1/10th lift ratio stil work for these large shells, im sure you could put less powder in, so something like 1/12th or even 1/16th...Im not sure, it would depend on my powder.

 

I use 1/10 of the shell weight of my homemade 2FA. I think I could lower the amount but it seems to be working well for me and I have no easily accessible testing area, so I hate changing things. I think I will try 1/12 soon just to see and hopefully lessen the material consumption.

[GalFisk]

Win20 works well to cut or pump, use water with some alcohol to wet the comp (less than 25% alc or the dextrin won't take). The stars become very hard when dry.