Scrambling Comets

[davis050594]

I don't really plan to make any of these anytime soon, but I'm curious as to how these are made and the skill level required to make them? Does anyone have experience and/or good results with them?

[Ralph]

Dont have experience with these in particular but there are two ways that you could do it both of which I have done

 

large gogetters could be used (tube with fast burning composition)

 

or if stars/comets are unevenly primed (like only a corner is primed) they tend to fly erratically through the air. Ive seen this happen with high metal content compositions and heard of it being common in some AP compositions

[optimus]

There's an autopsy of a scrambling comets mine on passfire here:

 

http://www.passfire.com/archives/issue6_2/autopsy6_2.asp

 

Don't currently have a subscription but from what I can remember, they're basically cavity comets with nothing in the cavity, wrapped/dipped so as to only take fire on the cavity end. In terms of skill level it's pretty basic stuff, just need a cavity pump. Could probably get away with using crossette tooling too.

[Mumbles]

The cavity is filled with black match and some BP slurry to lock it in. The edges are coated with paint, but pasted paper or any other number of coatings would probably work.

 

I personally think that method is the chinese adaptation (cheap) of go-getters as we know them. I believe there were a few people messing around with this on passfire a couple of weeks/months ago. I'll see if I can find it. It stemmed off of some mention of parlon bound stars flying around when bound around blackmatch or visco. Michael Fales had a special tool made by Rich Wolter to make these cavity comets. I bet you could use crossette tooling as well, just light them from the opposite end. Michael's tool had a thinner just cylindrical cavity, and I want to say it went all the way through, much like roman candle tools.

 

The ones in the autopsy have the entire cavity filled with the BP slurry it appears. I kind of wonder if this is just out of convenience, or if it is intended to give a bit of a delay before the stars start to jet around.

[Karlos]

watch 0:15. Cavity or round stars coated in inert material with hole? Mumbles: how long are cylinders with cavity? Short or long?

[Mumbles]

The pictures I saw looked like normal sized comets. About as long as they are wide, if not a little longer. I don't know if it matters all that much, they burn from inside out, not end to end. Except for the slurry a 1" long or 4" long comet will burn for about the same duration.

 

As far as that video, your guess is as good as mine. I've seen mini-gogetters in one of the best of AFN books. Perhaps you could use them as a core or something. Then agian, those look like the competition quality japanese shells. They may go through the trouble of drilling out every core.

[davis050594]

So does a cavity comet just look like a crosette except it's a circular cavity rather than a circle with four points for it to break?

[Mumbles]

The cruciform cavity is apparently a pretty recent innovation. Most old time makers still swear by a cylindrical cavity and rolled shots. Crossettes can very easily be made from a cylindrical cavity, just break into between three and five parts generally, where the cruciform more consistently gives four. When you see a master demonstrate the older techniques, you can certainly not argue with the tooling.

 

The scrambling comets made like this I've seen generally have a thinner cavity. That is probably tunable though. I've never made them that way, so I really don't have too many details.