Commercial rosette or TI salute shell spark effects

[pyrojig]

I have in past disassembled a commercial areal 2.5" salute shell . Interesting assembly and simple method used. The time fuse heavily primed in NC/bp slurry 2.5 sec. Delay. Into a shell with what appears to be seed or a type of rice hulls coated with a comp. Which I assume is perchlorate, charcoal, and metal (either ti of al. Fine maybe 100mesh or a tad coarser ) Like bp hulls with fine metal 5-10%ish of comp. This takes up half of the shell as a filler. The other half is obviously flash powder in a folded rice paper bag( to separate it from mingling with the hulls)

The effect is a short spark effect similar to just adding large grapenuts ti sponge to a areal flash salute. .. just a interesting tid bit i thought would be interesting to share .

 

If anyone has any idea of what they use (comp) to coat the hulls with , please share. It would be nice to find a spark producer for areal effects v.s. large ti sponge (expensive).

[pyrokid]

Is the shell supposed to function as a two stage device, where the fuse ignites the hulls, which then ignite the flash?

 

We know that classical rosettes derive their visual effect from burning aluminum, so it would seem to follow that some form of aluminum or mgal could be made to work here too. In a two stage device, the metal particles would already be burning when the flash is lit, and the subsequent explosion would disperse them.

 

It is certainly sad to see the effects of Chinese and American regulations on the prevalence and quality of salute shells. Chinese manufacturing restrictions mean that most salute shells cannot be filled to their volumetric maximum with flash powder.

[davidh]

Rosette is discussed in Fulcanelli (Pyrotechnica XI, page 31). Making the comp is not without risk. Definitely not without risk.

[pyrojig]

Thanks for the reply.

Yes the metal laced comp hulls is lit first then dispersed upon ignition of the flash( which is about 80-90g on a 2.5" and a 3" is about 100g flash. Sadly about half volume. But the booms about the same for fully filled shell (American);

I'll check my volumes for that chapter on the Italian manufacturing of those .. just don't remember if it went through the process of coating hulls/seed. I know they granulated chlorate flash for the effects back in the day. Now superseded by flash and TI

Edited November 8, 2021 by pyrojig

[pyrojig]

Just as I suspected, pyrotechnica 11 only shows the traditional granulated chlorate flash with antimony. The effect is more a softer bang and a spider web effect vs the TI spark floating particulate.