9 replies to this topic

[sasman]

Hi
I am going to try to make some double petaled ball shells has any member got any tips on making them?.. I want to try using a 6" plastic ball shell and a 4" inner petal .. Passfire shows how to make a 6" paper shell but uses KP as a burst charge.I would like to use BP burst charge + a booster..has anyone got any videos of there double petaled shells in action

Thanks

[Mumbles]

I've heard using a harder burst in the inner petal helps. So maybe use straight BP in the outside, and a few grams of flash or whistle in the interior petal. I can also say that using a plastic shell as the inner petal is much more difficult. I'd suggest pasting over one with paper or something and cutting it off and using that. Drill holes in it too. I have yet to successfully make a double petal. I am 0 for 2. The first had bad burst and just plopped open and spilled the stars out. The second one, in the process of taping the shell shut I think I broke off a lot of prime, and blew about 70% of the stars blind. From what was there it seemed rather symetrical though. These were 6" paper ball shells with 3" inner petals, broke with KP.

[sasman]

Well here is my first try at double petal..I didnt take any pre assembly pictures.. this was a very rough bodge to see just if i could get any sort of decent break & symmetry..The burst was BP coated rice hulls..+ flash booster.. i used a very large petal 4" because thats what i had handy..The stars were tiger tail to flash core + red to green..You could see nice green but the video doesnt pick it up at all..The stars are what i had handy..Next time i will roll up some stars specifically for the double petal shell..

I also put a ring of red stars at the seem of the outer petal but you cant realy see them only on the far away shot can you see a few of them..

The inner petal looked crap ..didnt look anywhere near round but from a greater distance it looked not to bad?..

I am trying to figure out what stars to make next to make a good effect..

Edited by sasman, 25 October 2010 - 09:27 PM.

[Mumbles]

In the third video the pattern looked pretty decent actually. In the others, not quite as good.

I am now 0 for 3 on double petal shells. This last one I got pretty close. I over estimated how easy the stars were to light. The inner petal was decent, but the outer petal of better pearl stars largely blew blind.

I do have to ask a question. Is there any reason you still use plastic? Every other accomplished shell builder I know switched over to paper very soon after first experimenting with it. I still feel it gives better symmetry and nicer breaks. I've used plastic quite a bit too, and found I had to break the shells pretty hard to get a good pattern, which tended to make some effects harder to produce.

[karlfoxman]

Rob I think either your inner flash was too hard, or the shell was not packed hard enough to make a decent wall for the inner petal. Nice shell though, I would make the same shell with a 3" inner petal and use less flash. It should work better that way.

[ravaz]

What did you use for the inner petal? Did you form a cavity using a hemi wrapped in tissue paper, or did you use an actual hemi? I'll have to agree with Karl on the inner petal. The pattern of the inner petal was off probably because it wasn't packed in well, and the stars migrated away from the walls.

[ravaz]

The second one, in the process of taping the shell shut I think I broke off a lot of prime, and blew about 70% of the stars blind.

If you're breaking off prime this easily, then you should re-visit your prime or priming methods. If your stars can't take a beating when closing the hemi's, and tapping on them to shut, then there is no way they will survive when the shell breaks.

[sasman]

Yes the inner petal was plastic...I glued the inner petal together before i placed it in the outer shell...the stars were packed solid and flush against the shell wall...the poor shape of the break hopefully was due to much flash..

Mumbles i use plastic because it seems to work ok.. i have some paper shells but i cant be bothered yet with pasting them in or using gummed type.. if myplastic shells perform ok i will use plastic.. but if i cant get these double petal shells working i will switch to paper.. My next try will be using a 3" inner petal & i will knock down the flash booster.just as Karl suggests.I will post pictures next time..But it will be a few weeks , i have yet to make some stars for the shell

Edited by sasman, 04 October 2007 - 06:37 PM.

[Mumbles]

My primes are normally fine as far as adhesion. I do believe I overfilled them with burst however. Instead of taking them apart and removing some burst I decided to beat on it until it closed. It did eventually close after some severe work. I know the prime system works, as in other shells of the same batch the stars lit just fine.

The last shell I blew blind was due to no prime at all. Apparantly better pearl stars at least need a green meal prime.

Sasman, you say you sealed up the inner shell nice and tight. Did you drill holes in the plastic casing to allow passing of fire. If not this may have been part of your problem. The inner petal could have exploded too hard in a sense in relation to the outer petal. This might have had some effect on the symetry. I'm not sure what kind of effect the enhanced pressure would have, but probably something similar to overbreaking a shell.

Edited by Mumbles, 05 October 2007 - 03:19 AM.

[Jerronimo]

That shell still looks very nice sasman.
I never made a true double petal shell, the biggest shells I've made are 4 inch, I mix the stars with the ricehull burst.
But why use a plastic shell to contain the inner petal? I would use a simple very thin shell of kraftpaper to hold the inner petal in place.
You could use a 3'' plastic shell as a mold, and just paste a few layers of kraft paper around it.
I would also not assemble the inner shell first, but fill each complete half and then snap together as normal.