Cavity stars

[pyrogeorge]

I would like to know some information about cavity stars.

Has anyone make this type of stars?It easy to make or need a lot of time?

I thinking to buy cavity star tools but first i would like to know some info about this stars.

[AdmiralDonSnider]

Do you refer to star pumps which form a trapezoid cavity, which is then filled with a "transition" composition, or to go getters?

[pyrogeorge]

Yes,i mean the trapezoid cavity pump.

I saw a video with green glitter comets and i think that is cavity comet.

Very nice effect!

[AdmiralDonSnider]

Very many simultaneous comet effects are in fact made with "married" comets rather than "tipped" (cavity) ones.

 

I once opened a thread about these kinds of effects: http://www.amateurpyro.com/forums/topic/5208-fancy-comets/page__p__68519__hl__%2Bfancy+%2Bcomets__fromsearch__1#entry68519

[warthog]

When I first got a cavity pump off of a friend I thought I could use it to make the same kind of comets/stars as you did George. It doesn't work very well. They wind up separating once they are lifted or shot out of a shell so you get a tiny color star and a glitter star traveling in different routes through the air and not what you had hoped. Married Comets, as the Admiral suggests, are the way to make a colored star with some sort of tailed effect like glitter. Since they are wrapped and pasted, they don't fly apart under the stresses of launch and they look like a dot of color trailing a tail of some type behind them. I am still trying to figure out what a cavity pump was created for and why they seem to sell so well. I am sure someone will chime in here and tell us and then perhaps I will get some use from mine.

[californiapyro]

The use of a cavity pump is twofold. The first use is to make a color changing star, by wrapping the end where both comets are showing, and wrapping the side as well. This creates an interesting change, sort of "streamer to colored streamer" or "tiger tail to red tipped tiger tail" and the changes are very consistent. The second use is to create a married comet effect. The way this is achieved is by making the comet shorter so the center comp is showing at both ends. The end where the center comp is thickest is wrapped, and this keeps the center comp from falling out. This is how people create the married comet effect with a cavity pump. Of course you can always fill the cavity with slow flash and see what happens

 

-Hunter

Edited June 12, 2012 by californiapyro

[AdmiralDonSnider]

They wind up separating once they are lifted or shot out of a shell so you get a tiny color star and a glitter star traveling in different routes through the air and not what you had hoped. Married Comets, as the Admiral suggests, are the way to make a colored star with some sort of tailed effect like glitter. Since they are wrapped and pasted, they don't fly apart under the stresses of launch and they look like a dot of color trailing a tail of some type behind them.

 

I never had a problem with "tipped comets" (made with a special cavity pump) separating into the streamer and color portion. If this happens the color comp has not been pressed into the dried streamer comet correctly. It is advisable to use your hand pressure or a small rod to fill the cavity like a dentist fills a filling and to level the end with a spatula. Both tipped and married comets are pastewrapped, so this does not explain different integrities.

 

The real problems I had with this kind of "tipped comet" way of realizing the simultaneous streamer and color effect is that

 

a.) the comps easily overpower each other (perception) and

b.) the system is not very tunable i.e. with the same comet and cavity size each time you have to match the two comps well in terms of burn speed. Some especially slowburning colors seem to be excluded by the system itself.

 

 

This is how people create the married comet effect with a cavity pump.

 

 

The way I read married comets are made is by pressing a long streamer and a short "waver" portion separately (with optimum, previously determined lenghts for each combination of effects) and gluing them together after drying, followed by pastewrapping the side of the comet to leave both ends exposed. These ends are primed, if necessary. Hardt describes them in a little more detail. As Mumbles pointed out in the other thread, this is a tunable system. Married comets however do not "transite" effectwise.

Edited June 12, 2012 by AdmiralDonSnider

[californiapyro]

yes you are correct about the married effect construction admiral, what I was saying was that effects that look SIMILAR to married comets can be created with a cavity pump. Sorry if what I said was confusing.

 

-Hunter