Prime between Colors ?

[CrashLanding]

Is it sometimes necessary to use primer between colors in a rolled color changing star ? I have rolled color changing stars only three times. I have rolled stars only three times. The first two were red to blue and blue to red. These worked perfectly. On my third attempt I rolled blue to yellow glitter stars. The blue stars seem to ignite reliably. But the yellow glitter star underneath ignites unreliably. I'll attach a picture I took the other day of a 4" shell using these stars. You can see that all the blues seem to be ignited, but only some of the yellow glitter ignited. It's still a nice effect. I accidentally made these stars larger than intended.

[Arthur]

Blue comps do sometimes burn cooler than other colours (it's relative! somewhere in the thousands of degrees) possibly an interlayer between from a blue to any other comp would help. However in small stars maybe the inter layer would take too much time.

 

Above all, if it looks like it needs an inter layer, then try it! Being of course aware of changes in possible reactions between the layers.

 

Sometimes an interlayer will cause a dark time, which may assist in getting colour changing stars to APPEAR to all change at the same time. Something that "appears later" will likely have a large amount of a dark relay comp so that the effect is seen when the stars get to the right place

[MadMat]

This is a good website for compositions http://pyrodata.com/composition/stars. If you look up "changing relay" under the primes section it will give you a number of compositions. Pick out the one which is suitable for the star compositions you are using. These relays are also useful for creating a "barrier" between two compositions which may otherwise be incompatible.

[Mumbles]

Changing relays aren't really all that great of primes in themselves. They are relatively dim burning compositions that accentuate the color change. They also provide a barrier like MadMat said, so that the colors don't mix and muddy up the color change. You might find that you need a real prime, or heat up the relay if you're still having ignition issues. On the positive side, the stars are moving much slower during color changes, so the amount of prime required often goes down.

 

They're fine for organic stars, but might have trouble with metallic stars or other slightly harder to light compositions. You can definitely add metals to either of the relay compositions listed, though that may affect the dimness. Silicon would be best if you want to combine the dimness and priming ability.

[drtoivowillmann]

Dear Friend:

 

Yes, you should.

There are two reasons.

1st: When the star begins with a "cold" composition like willow or glitter, followed by a "hot" one, based on perchlorate, nitate, carbonates, magnalium and resins. Otherwise the 2nd would not light.

 

2nd: Even between two similar compositions there always should be a so called "blind composition": high heat output, low light output.

Between Magnalium colours generally made with Barium Nitrate, Potassium Nitrate, Magnalium resins and binder.

The colour change will be sharper, without forming those ugly colour mixes, which often can be seen in the very moment of the colour change.

 

Yours truly: Toivo