Shimizu Violet

[Merlin]

Made a batch of Shimizu Violet today. Since they contained red gum and parlon I decided to cut them as there were no instructions. Are these a particularly long burning star? The only change to the formula was 5 % Ti added. Acetone was the solvent but when priming I used 75/25 water alcohol as my prime had dextrin in it. 4 hours in drying box. Out of a star gun they went all the way up came back down glowing red. My Gary Smith orange was prepared similar but burned out at peak height. Just wondering if I messed up using water to bind the prime?

[NeighborJ]

I am surprised it lit at all. I made a batch and used acetone as a solvent, it would not lite with any prime I normally use. They are meant to be bound with the dextrin not the red gum.

By the way, when bound with acetone they burned for a very long time. Bound with water, they were perfect.

[Merlin]

Thanks neighborJ. more wasted comp. The formula didn't have dextrin. just parlon and red gum. Too bad they looked nice going up but not so much coming back down.

I used a formula on a post here by Crossout.

Edited September 21, 2016 by Merlin

[Mumbles]

I'd suggest getting or checking the formulas from the source, though even that has SGRS as the binder. Dextrin and SGRS can both be used in similar applications though.

 

In most cases parlon binding speeds up stars from what I've seen That is mostly with metallic stars however. It could be different for organics.

[braddsn]

I will make a suggesting Merlin: And it's only a suggestion... I would suggest using dextrin/water as your binding method with all stars. I don't know if you roll stars yet, but when you do, binding with red gum or parlon can be tricky. Dextrin/water is a very effective and very simple method, and non-messy/sticky. I know that binding with parlon and redgum can result in stars drying faster, but that is not always better. Plus, if you mix different binding methods, you will certainly have different burn rates with your stars.

[Merlin]

All good suggestions. The error is mine because I did did not confirm the original source. If I had I would have seen the formula was wrong. It lists sgrs or dextrin as binder in which case I would have used water. I will make another batch the correct way though I am curious why the current stars burn so long and leave slag yet are the correct color. They do look good but fallout is unacceptable.

Braddsn to answer your question yes I do roll, pump and cut but do not employ one method over another. I still have on my list N1 over blue. Sometimes a formula even the correct one does not specify cut, rolled or pressed. When it does I use the specified method when it does not I am left to guess. I would not attempt to roll stars with parlon or red gum as a binder because they are sticky enough just cutting and separating. All the stars I have rolled are dextrin or sgrs. When I first started I used the Veline and G. Smith parlon bound stars intended for cutting. I suppose the Shimizu Violet would be rolled or pressed in which case I would roll. I use a cement mixer for rolling.

[Maserface]

Boy this is a real head scratcher!

Have you cut a star in half? Is there any chance they were still wet inside?

[Merlin]

I used the wrong formula. The were meant to be bound with dextrin. I bound with acetone. I have tried a couple more out of a star gun and I think since there are the right color I will add a little to the time fuse and break higher. I ran across another comp all together which was parlon bound and it noted a long burn time. Maybe just a characteristic of some parlon bound comps.

[NeighborJ]

Yeah, mine burned for 15 seconds during a test. But only 3 when made with water. Big difference.

[CrossOut]

sorry im late to the party on this one.

 

I admittedly forgot to mention the binder my apologies for your wasted comp. i copied the formula from my notes and i intentionally did not include dextrin or SRGS as i bound using alcohol / phenolic resin which works great with these stars. i wouldn't recommend water and dex for this comp if you are rolling your stars. SRGS is better. The reason i say this is because the high parlon content seems to make the stars less dense while rolling. ive honestly never cut these stars so i cant really comment on the performance there. As a attempt to salvage the stars, you can try washing off the prime layer with water. after letting them dry you can try step priming the stars with some hot metal based prime. it might work. As others mentioned, acetone usually speeds up burn rate. but reduces reactivity as it can form hard to burn layer on the star.

Edited September 27, 2016 by CrossOut

[Merlin]

Actually on further tests a few days later they worked reasonably well. The colors are excellent they just burn a bit longer than expected. Using a 4 inch there should be enough altitude to allow complete burn out. I may mix with fire fly or TT so as to not to distract from color which is a true Violet. They. are not totally wasted just won't use in a 3". As you suggest next time I will roll with SGRS. Thanks