1569 replies to this topic

[chris17]

Hey Karlos,

As I understand, you are asking how the insure prime ignition? I assume you make round stars in a star roller. If you think that your prime fails to light, you should try to get your stars to spike during rolling of the prime. Spiking refers to the prime forming a slightly bumpy surface on the stars, which will aid ignition. You can achieve this by during the rolling operation, making larger than normal additions of prime powde and using very litle water with no alcohol. The star surface should start to take a somewhat uneven form. The spiking should not be excessive, just enough to have few sharper edges for easier ignition.

Edited by chris17, 18 February 2008 - 02:06 PM.

[KarlosH]

How can I spiking? With special surface in roller? I don´t understand:-)
Japanese stars have often smooth surface....or not? They must have a know-hov, for 100% ignition....maybe my charcoal is poor, and Black powder hard to ignition.

[chris17]

How can I spiking? With special surface in roller? I don´t understand:-)
Japanese stars have often smooth surface....or not? They must have a know-hov, for 100% ignition....maybe my charcoal is poor, and Black powder hard to ignition.

Sorry, it's a litle hard to explain. If you look at the picture above, you can see that the star surface is not smooth, but has small bumps here and there. Thes 'bumps' will catch fire more easily and make your star ignite. To achieve the bumpiness, make oversized powder increasement in you roller. This way, the distribution of composition will become uneven and bumps will form.

[paul]

First of all, you´ve got alot of skill, KarlosH! Great shells, I especially like your last ones, the green one kicks ass!
Chris17 is right. You have to use a step-prime to get some compositions going!

That is: Core: hard-to-ignite comp ---> black powder with added metal -----> bp outer prime.

That way the cores should ignite easily!


Heres my new shell: Click me babey!

[karlfoxman]

Yes for hard lighting stars I use step prime, my Maltese shells comets use step prime. I use 1" comets and the formulas are lightly modded Veline ones. The prime is 50:50 BP:Original comp, they light everytime very well. The comets are pumped with a press and then dried, when dry they are sprayed with water:meths mixture and rolled in the prime till coated all over.

Paul: Loved the shell, worked very well. I was supprised the comets came out well because they did not look locked into place against the shell wall. But well done, only think I would say is it went too high. But that could have been the position of the camera. Shame the comet tails came off, I had a 2" comet break apart ontop of a 6" purple shell of shells once. Was gutted!

Whats next for your shell building now? Im planning on trying some more stuff, maybe an Italian shell of some sort. And some more Maltese ones, Im going back to Malta from 27th May - 10th June so I shall have some more ideas.

Well done on your work everyone!

[paul]

Paul: Loved the shell, worked very well. I was supprised the comets came out well because they did not look locked into place against the shell wall. But well done, only think I would say is it went too high. But that could have been the position of the camera. Shame the comet tails came off, I had a 2" comet break apart ontop of a 6" purple shell of shells once. Was gutted!

Whats next for your shell building now? Im planning on trying some more stuff, maybe an Italian shell of some sort. And some more Maltese ones, Im going back to Malta from 27th May - 10th June so I shall have some more ideas.

Well done on your work everyone!

Yeah, sometimes even pics don´t tell everything In this case, spiking and the four layers of well impregnated kraft
paper put lots of pressure on the shell, so there was not even a slight sound of movement when shaking that shell!

The break was quite "round" for a cylinder, maybe this was due to the fact that I´ve tried to build it like
a "traditional" italian cylinder shell like fulcanelli...

Next will be a 6" cylindrical shell again

[KarlosH]

Chris, Palul: Thanks, you opened eyes to me. I wanted allvays have a surface of my stars smooth and perfect.... It´s right, when I added a much of Blackpowder to roller, stars was bumpy...but I always added water or alcohol for perfect rounded and smooth surface....OK, never more.
Myebe is convenient final addition of fine granulated blackpowder or not?
Paul: Star comp: BP, 50:50??? This is wasting with coloring agents!:-) I thing that better is composition like in shimizu perchlorate igniting composition and thin final layer of BP or not?:-) Thank and bye bye. New shells will be perfect. I hope...ehm.

[pyrotrev]

I often use some fine granulated bp to aid ignition and it works well.

[pihop]

Some quick made shells just for testing different kinds of lift:
http://uk.youtube.co...h?v=-a4LZPXjWGo

My next project that im working on is one 6" Bow tie /w ring and one 6" kaleidoscope /w crossing rings. Will post video when it's done!

[karlfoxman]

Nice shells, but I think you need look at your timings. The shells seem to be on their way down when you fire them. Work on that before you start on a 6" shell.

[paul]

Wow! That third shell looked like a thousand colours shell
What I´m wondering about: The lift looks and sounds quite
powerful, but they don´t seem to get tooo high! Was there
much space between shell and mortar?

@ Karlfoxman: I think timing on shell 1 and 3 is improvable,
for shell 2 it just seems right (not a whole second after apogee)...


Anyway: Nice shells there!

[dr thrust]

may i ask what the stars were in the last shell, they were amazing!!!!!

[karlfoxman]

Paul: On second look your right, last one looks pretty good. I do like the stars too, very tasty. I like dense breaks and so thumbs up from me. I might talk to you regarding pistil stars on my next maltese shell.

[pihop]

Thanks for the nice comments guys!

Regarding the timing, I didn't even measure the time fuse for these shells i just cut a "lagom" piece like we say in swedish.

paul--> The lift is just fine it's the position of the cameraman that makes it look low. The cameraman is placed about 300' (100m) from the mortar on a hill that might be 30-45' (10-15m). If you read the description you will see what kinds of lift i used. The 1st shell is a plastic 2 5/8" shell thats supposed to be launched form a 3" mortar but my mortars are 3 3/8" so the fit is kind of worthless.

The last shell actually didn't even hit it's apogee it just blew away from the camera.
The stars in that one were actually scrap stars, the green ones were under primed 5mm emerald green rolled on robbed dragon eggs.


Here are 2 failed 3" that i made for testing some more lift.
1st one is lifted with 15g cork BP and 2nd one is lifted with 15g cork/newspaper bp 50:50.
http://uk.youtube.co...h?v=PU_2zsqnYps


By the way guys. For my 6" shells im planning on using BP as break, will this be strong enough to break the shell HARD if I paste about 30 layers or more?
For my 4" bow tie shells I'v used BP on hulls with a 2g flashbag with great results. Will a 2 or 3g flashbag overbreak the 6"?
I'm looking to get as good break as in the first and last ones in my earlier video ( http://uk.youtube.co...h?v=aPLszMNv7yY ).

Edited by pihop, 25 February 2008 - 10:59 PM.

[KarlosH]

Pihop: You need only good lift! Stars are nice, mainly double-color stars. Nice.
Karel.