12 replies to this topic

[JWC1947]

I made some small shells about golf ball size, and they worked just fine except when the burst went off the stars seemed to fall down word instead of out word, I would like some advice on the burst charge amounts to use for the different size shells, also like to know if i should mix BP and flash powder together for burst charge or use other comp...Thanks

Edited by JWC1947, 04 March 2007 - 02:50 AM.

[portfire]

Hi JWC1947 and welcome to the forum.

breaking shells that small usually requires a booster in the burstcharge,like flash powder but people tend to use whistle mix.

also please use the search function,it's all here

http://www.pyrosocie.......ic=2195&hl=


regards
dean

[JWC1947]

Hi JWC1947 and welcome to the forum.

breaking shells that small usually requires a booster in the burstcharge,like flash powder but people tend to use whistle mix.

also please use the search function,it's all here

http://www.pyrosocie.......ic=2195&hl=
regards
dean

Hi Portfire, Thanks for the welcome to the forum;
I found a variety of usable information in the searches about burst charges for shells, but I did not find a forumla for burst charge in grams-weight for different types and sizes of breaking shells, (please correct me if I am wrong) I assume you have to use trial & error method for each size shell...

[BrightStar]

I assume you have to use trial & error method for each size shell...

Hi JWC, yes, it's basically trial and error. The burst charge serves the dual purpose of propelling the stars and holding them in place beforehand, so in terms of quantity you just fill the shell with as much burst as it will take...

For a small 1.5" golf ball shell, maybe try granulated BP mixed with approx 0.75g of flash or 1g of whistle. There are some interesting examples of small shells here:

http://www.creagan.n...ks/mortars.html

Edited by BrightStar, 04 March 2007 - 05:39 AM.

[JWC1947]

Hi JWC, yes, it's basically trial and error. The burst charge serves the dual purpose of propelling the stars and holding them in place beforehand, so in terms of quantity you just fill the shell with as much burst as it will take...

For a small 1.5" golf ball shell, maybe try granulated BP mixed with approx 0.75g of flash or 1g of whistle. There are some interesting examples of small shells here:

http://www.creagan.n...ks/mortars.html

Hello BrightStar, This is vary helpful link thank you, what ratio: of granulated BP mixed with 0.75g of flash would work best so the stars will not blow blind...

[Mumbles]

What he means is to fill the shell as normal with stars and BP, then add your flash or whistle. The flash and BP is not mixed up ahead of time usually. The amount of flash/whistle will usually need to be dialed in by each person for their shells. Everyone has different materials and methods, and thus requires a slightly different burst.

Another composition to try is KP. This is generally what the commercial festival balls use. 10:1 ratio KP to rice hulls or carrier is fairly standard with such small shells. Sometimes with additional finely granulated KP added to boost the strength.

Addionally stars blowing blind is not usually something you change your burst for. If your stars are being crushed by the burst is when you change your burst. Stars blowing blind is when you change your primes.

Edited by Mumbles, 05 March 2007 - 01:25 AM.

[JWC1947]

What he means is to fill the shell as normal with stars and BP, then add your flash or whistle. The flash and BP is not mixed up ahead of time usually. The amount of flash/whistle will usually need to be dialed in by each person for their shells. Everyone has different materials and methods, and thus requires a slightly different burst.

Another composition to try is KP. This is generally what the commercial festival balls use. 10:1 ratio KP to rice hulls or carrier is fairly standard with such small shells. Sometimes with additional finely granulated KP added to boost the strength.

Addionally stars blowing blind is not usually something you change your burst for. If your stars are being crushed by the burst is when you change your burst. Stars blowing blind is when you change your primes.

Ha Mumbles; Nice to hear from you I appreciate all the good Info, that's why I joined the forum to learn from veteran pyros that have the knowledge, I hate to sound like a dummy but I keep seeing KP used instead of BP (Black Powder), what comp. is KP (? Powder)

[Frozentech]

I hate to sound like a dummy but I keep seeing KP used instead of BP (Black Powder), what comp. is KP (? Powder)

KP is Potassium Perchlorate - 70
Charcoal - 18
Sulfur - 12

+5 Dextrin to make it stick to your burst carrier, usually rice hulls.

More kick than BP, helps when there is not enough room in the shell for enough BP to do the trick. Best for smaller shellsm, I use it up to 4" shells, and add 1gr of flash for 3" ball shells, 1 1/2 gram of whistle for 3" canisters.

[karlfoxman]

Remember KP burns faster under higher pressure, so a thicker shell will control the break.

[JWC1947]

KP is Potassium Perchlorate - 70
Charcoal - 18
Sulfur - 12

+5 Dextrin to make it stick to your burst carrier, usually rice hulls.

More kick than BP, helps when there is not enough room in the shell for enough BP to do the trick. Best for smaller shellsm, I use it up to 4" shells, and add 1gr of flash for 3" ball shells, 1 1/2 gram of whistle for 3" canisters.

Hi Frozentech, thanks I will have to get some Potassium Perchlorate shortly, in the mean time I am going experiment with a little portion of flash added to my BP and see how it works... Thanks Again

[JWC1947]

Remember KP burns faster under higher pressure, so a thicker shell will control the break.

Hi karlfoxman, ok I will try a few more layers on my shells and see how they break, thanks...

[seymour]

JWC1947, What flash are you using?

[JWC1947]

JWC1947, What flash are you using?

Hi Seymour, Potassium Nitrate 70 Aluminum 30, I don't have any Potassium Perchlorate. I would appreciate any info anyone could give me... Thanks

Edited by JWC1947, 12 March 2007 - 01:35 AM.