The strange behavior of the strobe core surrounded by a phenolic resin based mix

[MinamotoKobayashi]

I do not understand why, but when I roll a water based strobe core with a mix containing phenolic resin (I use Jopete's RED and Jopete's GREEN),

the strobe burn without effect. I found only ashes, without any flash. But when I break the star and extract the strobe core, and ignite the core alone, the strobe works well !!

The strobe works correctly also if I use red gum instead phenolic resin in the red or green mix.

As usually, I use Monocapa between strobe and coloured mix.

The stars were perfectly dried: I used a mix of 50/50 ethanol/acetone and waited until the batch do not lose weight anymore.

Anyone can explain me this please ??

 

[Blackmach]

I also had trouble mixing water-binding comps and alcohol / phenolic-binding comps. I don't know what the solution is, but at the moment don't mix comps with water and comps with alcohol.

[kingkama]

I think that's depends from the temperature of burning of monocapa, it destroy the first layer of strobing, and let two or three flashes if you look at the star burning you see the color fading out then the stars strobe one or two time.

[MinamotoKobayashi]

I do not think that the issue is the Monocapa: if I break the dried star and extract the monocaped core, the core works well!

Also, take a look at my last shell:

 

https://www.youtube.com/watch?v=mfVVekn0p0c

 

These were stobe stars only, with a thick monocapa prime, and the ignition was perfect and long lasting also with smaller stars.

Also, all my old shells was made with strobe core stars (water based) and red/green comps around (alcohol based).

But in this last batch I changed three things;

 

1. I used phenolic resin instead red gum;

2. I eliminated the water in the Jopete's formulas;

3. I used a mix of 50% ethanol 50% acetone instead only alcohol (ot alcohol/water).

 

So the issue should be sought between these variants, but I feel that the problem is phenolic resin.

 

if I have to be fully honest, lately I had a lot of problems with phenolic resin, especially for the biblical times for the star drying, which despite using 50% acetone,

still remain in the order of a week or more also under a powerful airflow.

Edited October 10, 2020 by MinamotoKobayashi

[kingkama]

May be that I cannot explain myself well, it's not a problem of monocapa, but a problem of monocapa inside of a stars, imagine the burning temperature of a red metallic perchlorate stars using as additional combustible phenolic, what will happen to barium nitrate and MgAl and the Sulphur inside a hot burning shell formed by monocapa. If you don't use a layer between color and strobe is better, and also this prime layer is useless, is it wery necessary only if strobe are alone. The transition layer is mandative only if you are making color changing stars. This is my idea and my way of doing strobing core stars, I like a lot turquoise on the white strobe or Violet on the green.

[MinamotoKobayashi]

Ok now I fully understand what You mean!

But ... the issue do not appears if I use red gum instead phenolic resin in the coloured mix.

In fact I usually use strobe stars with monocapa layer surrounded by red or green with red gum as binding agent, not phenolic resin.

Probably the combustion temperature of the red gum is lower compared to the temperature generated by resin.

But since You tell me that the prime is not necessary between strobe and coloured mix, I will eliminate it.

I hope that the alcohol based Jopete's mixes grab well or at least enough to the water based strobe stars surface, otherwise I will be forced

to switch to dextrin as binding agent for Jopete's stars.

Edited October 10, 2020 by MinamotoKobayashi

[kingkama]

The alcohol you use for binding the outer layer contains a bit of water that dissolve also the strobe core, so they stick together. Red gum had a lower burning temperature, but i imagine that is also some on oxygen balance between oxidizer and combustible. Try a little batch (100 grams or so) and see if like how stars working. Remember that the core need some time to Dry because Suck moisture from the alcohol you use for outer layer. I think that if you switch to Dextrine green will burn yallowish or white is a common issue using Dextrine as substitute. Edited October 11, 2020 by kingkama

[MinamotoKobayashi]

Yeah, in fact I switched to alcohol just to avoid the fading effect of green (pale green intead brilliant green).

On the other hand with red mixes I never had any kind of issues: it always works, it is always beautiful and intense,

even if the mixture is still wet, with water, with alcohol or mix 70/30.

Usually, to facilitate the adhesion between the strobe mix (well dried) and the outer layer, I put the strobe cores inside

the star roller and run them for a long time, wetting them often and in a homogeneous way. Part of the external mix softens

and a kind of pasta is created which, once dusted with the colored mix, acts like a step prime, clinging very well to the strobe core.

Veteran admin Mumbles kindly taught me this system and it is awesome. Thanks Mumbles

Edited October 11, 2020 by MinamotoKobayashi

[kingkama]

Red loves hi temperature e carbon, green and blue are a bit snob they must to burn at proper temperature and avoid carbon. Let us know improvements.

Have a nice day.