Pirotex Posted March 18, 2017 Posted March 18, 2017 (edited) Name of composition: Flashing microstarsComposition Type: effect starCreator: Ronald LancasterColor/Effect: flash of light after a short delayPreparation: 100 grams of the mixture is kneaded with 20 grams of a 10% nitrocellu-lose solution in acetone to form a homogeneous mass. It is rolled out on a star plate of about 8- 10mm thick and cut into a few pieces. These are dried at room temperature for one day and then further dried in an oven at 50°C for five hours.They are then crushed into angular grains with a wooden mallet and an aluminium roller. Finally the grains are separated through a sieve to obtain small stars of 1.5 to 3.0 mm. Version 1:Barium nitrate 40%Sulfur 20%Magnalium (50/50) 40% Version 2:Stroncium nitrate 30%Sulfur 30%Magnalium (50/50) 40% I maked version 2 with 5% dextrin and formed 1.5 mm grains. Use in fountain 20 mm with BP 60/33/7 + 10% microstars.For this fountain need slowly BP, for example 55/35/10 or 50/38/12 (from book)More information in R. Lancaster FIREWORKS Principles and Practice 3rd Edition, page 150 http://savepic.net/8800807m.jpghttp://savepic.net/8801831m.jpgVIDEO: https://www.youtube.com/watch?v=rfXSBFJuzCIVIDEO 2: https://www.youtube.com/watch?v=HBFn4NgxkvI Edited March 18, 2017 by Pirotex 5
OldMarine Posted March 18, 2017 Posted March 18, 2017 (edited) Absolutely gorgeous!I liked it so much I just bought the book. I added Piro's rendition of those to my personal formulae on FW as well. I love me some gerbs!Also started a thread there on these stars as well. Edited March 18, 2017 by OldMarine
mabuse00 Posted March 18, 2017 Posted March 18, 2017 Great stuff I wonder why this actually emits green an red light, in absence of any chlorine donor and with so much metal. What diameter had the nozzle?
Pirotex Posted March 18, 2017 Author Posted March 18, 2017 (edited) OldMarine, 200 meshmabuse00, 10 mm Edited March 18, 2017 by Pirotex 1
OldMarine Posted March 19, 2017 Posted March 19, 2017 MgAl definitely needs to be on the small side of 200 mesh. My stars are hitting the ground before ignition. They have a smolder phase similar to crackle and strobes so the size of the metal definitely affects that delay time.
NeighborJ Posted March 19, 2017 Posted March 19, 2017 I believe if you reduce the amount of sulfer it will have the same effect. It sure has a lot of the stuff.
OldMarine Posted March 21, 2017 Posted March 21, 2017 (edited) Got another 100 gram batch with the finer MgAl made up and rolled out before the rains came in. Got it in the doghouse getting rid of the acetone and I'll put it in the dehydrator tomorrow. The scraps I tested are performing much better with only a slight delay.I dried the strontium nitrate overnight in my dehydrator before mixing and it seems to have helped the color. Edited March 21, 2017 by OldMarine
Ubehage Posted March 24, 2017 Posted March 24, 2017 I believe if you reduce the amount of sulfer it will have the same effect. It sure has a lot of the stuff.What is Sulfur's role in this composition? Is it fuel?
NeighborJ Posted March 24, 2017 Posted March 24, 2017 I see sulfer as a slag producing fuel which can be adjusted to increase or reduce the delay timing. The MgAl is just a light producing fuel which produces little slag but will still contribute to the delay by consuming oxidizer. 1
Sulphurstan Posted March 26, 2017 Posted March 26, 2017 Definitevely gonna try these! These cuties have a nice effect!
OldMarine Posted March 26, 2017 Posted March 26, 2017 Apparently Piro either had some other colored stars in the fountains or the color is a camera artifact. Though these make a wonderful bursting shower of sparks, I nor Ned G. have been able to get a bit of color from them and Ned did further reading and came up with this (from Fireworking.com)Ned quoted: "Pat, I think that there may be some confusion about the effects we're talking about. Upon following Mike's advice, and perusing Shimizu's exploration of "microstars" in PT 10, I realize the effect that is being striven for is the popping, branching white/silver sparking effect we're seeing in the vids of Pirotex's gerbs. The colored microstars that we're seeing in there must be being produced by actual colored microstars, different than the flashing microstars we're exploring in here. Shimizu discusses an effect similar to a crackle one or a strobe one, where there is ignition, a smoulder phase, and then the popping/sparking effect phase. I was under the impression we were looking to get a green or red colored star effect from Lancaster's stars, but, nope, that's not what we're looking for." End quote. Still a nice effect but not what I thought.... 1
dynomike1 Posted March 27, 2017 Posted March 27, 2017 I think this is where the misunderstanding might have came from. "flash of light after a short delay". Sounds like the star was a color till it burnt to the crackle. I the video the ones that i saw retained their color didnt crackle.
Pirotex Posted March 29, 2017 Author Posted March 29, 2017 Green stars in my fountain (1,5-2 mm):Ba(No3)2 - 50%Magnalium - 25%PVC - 10%S - 10%Dextrin - 5% 4
OldMarine Posted March 29, 2017 Posted March 29, 2017 Green stars in my fountain (1,5-2 mm):Ba(No3)2 - 50%Magnalium - 25%PVC - 10%S - 10%Dextrin - 5%Ah, there's the missing chlorine donor! 1
MasterBlaster Posted March 30, 2017 Posted March 30, 2017 Haha I just made these last weekend and came back today to find out why neither of mine were proucing any color. Glad to find out it's not just me.
lloyd Posted March 30, 2017 Posted March 30, 2017 It's definitely not "just you" -- but then, a lot of folks have mistaken a (basically white) strobe for a color star, because there were colored stars added in that demonstration effect. Eh... the absence of any chlorine donor is sort-of a 'giveaway' of how they'll perform. Lloyd 1
OldMarine Posted March 31, 2017 Posted March 31, 2017 I'm going to try cutting some tiny rubber stars and prime them with screen mixed BP. Those are fairly slow burning so maybe they'll make it out of the tube along with the sparky ones.
Mumbles Posted March 31, 2017 Posted March 31, 2017 You don't necessarily need slow burning stars if you have a slow burning prime.
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