Pressing multi colour stars

[Arthur]

I'm planning some colour change to brocade stars, I was considering veline red, veline green then to simple tiger tail. These are going to be large say 40 or 50mm DIA and likely 50 - 60mm high. I'm considering getting a tool and press and putting a spoon of red powder, a spoon of green powder then filling up with TT mix and pressing it. Then pasting the outside of the star with gummed tape so that it burns only from the veline end.

 

Has anyone actually tried a similar method, does anyone see any glaring incompatabilities?

[MeowMix]

I haven't tried it myself, but I've heard that there can be issues with the binding of the comps, due to mesh sizes and binder differences, but I'm sure that depends on the comps used. The only thing that I can personally see (With my admittedly limited knowledge) is that you'll want to make sure the measurements on each spoon is exact, because to me it seems that if they're not, they won't change comps at the same time during break.

[MrB]

I don't believe, can not believe, for a second, that adding 3 different compositions, spoonfuls at a time, to a star-press, and then consolidating them in one go, will create color-changing stars that will behave identical.

 

Press the stars different layers one at a time. Measure, by weight, how much composition goes in to each and every single star-layer. Press to identical pressure, and have either long dwell time, or identical dwell time. Ideally both, i suppose. Measure all the layers again, height, and weight, and only use those that match identical specs.

Pretty sure layered stars like these need relay composition as well, to make sure the colors wont mix as the fire transitions from one to the other. These would have to be done in the same way, and would be very fragile, since they will be very thin.

To stick the darn thing together, i would use a tiny drop of NC on the face of every layer, or, if that can not be sourced, an even smaller drop of superglue. Stack the star layers in the press, to get them properly lined up, and push them together without excessive force. The CA glue should only restrict fire in the immediate center, and give the whole thing structure enough to paste / dress with gummed tape, and survive the break.

 

While not as simple as just measuring stuff in to the star press, that "should" give you a bunch of stars that color-changes together. If the simultaneous change isn't needed, you are going to get some mixed results with the color in the transition layers, but other then that, it should work.

[Mumbles]

Generally the compositions, even similar ones like veline red and green, will dry at different rates and split apart while drying. Unfortunately, there isn't a good way to do this besides pressing out all the wafers individually and gluing and pasting them together at the end. Married comets like this are a lot of work. The color changes are difficult to make crisp. Additionally, since I have a strong feeling that these are for a 16" shell, I should note I've never really been a fan of pressed stars in ball shells.

[Wiley]

If I were me, I'd do it t'other way around: tiger tail to green/red. That's all personal preference though.

 

When making each color of wafer, fill your pump/plate to pretty well the same volume. Press all of a given color to the same pressure. When you eject and trim them, you should be trimming off about the same amount of excess every time.

 

Glue 'em together with a dot of white glue. Paste them in like you would crossettes, leaving the face of the first wafer to be ignited exposed. Prime with black powder slurry and press into grain powder.

 

It's easy to make things like this to burn way too long, particularly the color portion, but I'm sure you know that.

 

A variant of this idea that you might try is a married comet with a color-changing head. Basically do what you initially proposed, but paste such that both ends are exposed. Now you have a red/green comet which leaves a charcoal tail, which then changes to the opposite color, but still leaves the tail.

 

Using an inexpensive tremalon, like N1 made with a mixed mesh BP base, would be another option for your tailed portion.

 

Curious to see what you come up with!

[Bangkokpyro]

Married comets made the traditional way are in my opinion the best way to get the effect you are looking for. Careful consideration is needed to get the burn times right.