7 replies to this topic

[Sam Miller]

For example:

 

I've always loved these and was just wondering how the different comps are joined together. So you have a solid comet for the tail, going to the cavity part which is coloured comp, are the two mixes connected to each other in the crossette pump? or are the separate parts dried and joined after?

 

I hope to make some of these in the not to distant future and was just wondering on the best method of making them.

 

Thanks!

 

Sam

[cooperman435]

my money would be on the two being pressed at once into the single crosette, the red occupying the depth of the crosette pin and the glitter being the solid slug on top of it.

[Sam Miller]

I'll give it a go and see what happens

[Deano 1]

Good luck Sam, looking forward to seeing the results. 

[Arthur Brown]

I'd also suggest that I have seen blind stars in the clear up that had brown paper tape over most of the length and one end. SO perhaps the first colour is the primed part and the second colour is under the paper which lights from the inside as the croissette shatters.

[Mumbles]

Arthur, that is how all crossettes are made essentially, whether or not they're color changing. 

 

I actually had a special pump made to make these.  It's just an ordinary round hole crossette pump with a second depth stop hole drilled in it to allow me to essentially make donut shaped comets.  It's drilled such that the cavity part of the crossette almost touches the pressing surface.  

 

Pressing two drastically different compositions together and expecting them to stay together is probably not going to work very well.  If it did, making tipped comets or color changing  comets would be trivial and be done all the time.  The different drying rates of different compositions often makes the two compositions separate or weaken.  These have to be pasted anyway, so it probably wouldn't be a big deal.  I'd just personally prefer to make the two parts separately, and then glue them together with a little BP/NC slurry and paste them. 

[helix]

TR certainly seems to press his crossettes using 2 comps - have a look at this video at about 45 seconds in you can see a crossette with 2 distinct layers (it hasn't been pasted yet)

 

 

I would agree with mumbles, it would probably be better to manufacture these in 2 parts and glue together.  You would probably need modified tooling to do this, as I would think the fuse hole would be better formed in the cap of  composition that would be used to seal the main body of the crossette.  

[Arthur Brown]

Well I still suspect that the colour change is the exposed compound vs the papered compound, the second colour only showing after the split.

 

I rocketeer I once talked to said that he made pressed star cored grains in sections and glued them together and in place using the same compound to minimise thermal expansion cracking.