Colour changing stars dont change colour?

[klachner]

Hello,

 

i tried rolling stars wich will change from yellow to red. At first i rolled 6-7mm red "coreless" stars with this comp: http://pyrodata.com/compositions/Ruby-red , rolled a thin layer of prime (i used Meal with 10% silicon) on them and then i rolled the yellow layer (this comp: http://pyrodata.com/compositions/Sunrise-yellow) onto them and added another layer of prime. But if I light them they only burn yellow, no change to red. After they burned, there is no red core left, so the red part burns too... Maybe because the red burns while the yellow is still burning and so you cant see it? How could I fix this, i thought about using a delay comp, can anyone tell me a good one? Or are ruby red and sunrise yellow not suitable for colour changing stars?

 

 

[Mumbles]

The first thing you'd want to check is if the red core burns red on it's own, or if the formula or chemicals got contaminated somehow. There is someone on Fireworking right now mentioning that this formula is burning yellow for him as well and has pinpointed it to his strontium nitrate. If the cores are not dry, they can also burn yellow-ish for what it's worth.

 

If the chemicals and formula is fine, my next guess would be sodium nitrate leaching into the core. It's very soluble, and a very strong emitter. If this turns out to be the problem, applying the intermediate prime with a non-aqueous binder to create a barrier is one popular solution for dealing with incompatible layers.

[asdercks]

Yeap, I am having that problem with my ruby red stars but I think I figured out what is causing the yellow color...I think I mixed some barium nitrate with my strontium nitrate thinking I was mixing the same chemicals, should've tested the composition before I started rolling stars like crazy lol

[klachner]

i tested the red cores and they burned in the typical great ruby red - red and they were also dry, I already tried some streamer to ruby red stars some time ago, i used ruby red stars as cores and as second layer I used metal fire dust no35 comp, because rolled metal fire dust stars gave me pretty great results in previous shells, but rolled onto the red core I had the same problem. Only the metal fire dust "colour" was visible, the red from the core not, and the cores weren´t there afterwards so they burned... maybe you can tell me some comps which already worked in colour changing stars so I could try with these

[Mumbles]

Out of curiousity, how are you testing these color changing stars? You'd want to use a star gun, mine, or shell for the best representation. On the ground I could see these things happening.

 

Otherwise, I'll keep thinking about this. I don't have a good answer right now.

[klachner]

I tested the metal fire dust to red stars in a shell, but they burned like on the ground, you could only see the metal fire dust part...

[OldMarine]

I wonder if your outer comp is igniting your red comp before it burns out completely. Maybe try rolling on a thicker layer of a dark relay to protect your color core???

[asdercks]

Klachner last year I rolled some D1 to red stars and I noticed some of the cores were burning yellow instead of red when I tested them, well I found out that some of the stars were not totally dry because I started to see some condensation forming inside the bag where I had the stars stored Edited October 19, 2016 by asdercks

[OldMarine]

I have yet to roll a star but am studying up. Don't let this thread die without some resolution!

[braddsn]

I have a guess about what may be happening. I use nitrate reds, and I agree with Mumbles. Whenever I take a dry red nitrate core, and roll another color on top of it, the red core soaks up moisture and becomes soft again. I have discovered a work-around that works for me, here is what I do: I roll a thin prime layer onto the red core, then I roll the next color.. then I put the stars in a dehydrator that has a drying temperature of 180F. I leave them in there for about 30-45 minutes, then take them out. When they come out of the dehydrator, I can squeeze them and they are soft and smash between my fingers. Once they cool off (about 5 minutes), they become rock hard and are ready to use. It is interesting.. I can't really explain why it happens, but it does. This softness ONLY happens with nitrate red. Every other color stays hard when I roll other colors onto them. Keep at it and you will succeed,... here is a shell with the colors that you are probably trying to achieve...

 

https://youtu.be/A670_WxPCuc?t=7s

[FlaMtnBkr]

Like mumbles mentioned, I would try rolling a layer of prime that uses a different solvent that won't dissolve the red core. So if you use water with the red, use NC lacquer to roll the prime that uses acetone as the solvent. Then when you roll the second color you can use water again and not worry about chemicals leaching. Or you could use a different solvent for the second color like the NCL or phenolic and alcohol. I would probably want to use fairly pure alcohol that doesn't have much water in it or only make a few to make sure it's not enough to leach a highly soluble salt to the center.

 

Just what I would try first if you know the cores are working well on their own.

[klachner]

ok so I will let the stars dry until they are hopefully completely dry, and I also thought about a longer delay using a thicker layer of a dark relay comp... but I didn´t find any yet so which comp would you recommend for dark relay Firebreather?

[klachner]

little update... Now they are completely dry and now they work, they burn yellow and turn over orange to red

[braddsn]

Well done klachner!