Bind black powder with phenolic resin

[redbullzuiper]

Hi guys,

 

I'm making my primes usualy like so: BP + 5% Si + 5% Dextrin.

 

However, what happens if I replace the Dextrin with Phenolic Resin and bind it using Alcohol?

My guess is that the prime will burn faster, but other than that it doens't matter. Correct me if I am wrong.

 

Anyone ever tried? Or someone knows if this is going to work?

 

Thanks,

Regards

Edited August 21, 2018 by redbullzuiper

[Merlin]

I wonder the same thing. For example you have a supply of prime with dextrin. Do you use that on phenolic bound stars? From what I have read phenolic stars are virtually water proof so it seems dextrin being water bound might not adhere. Actually I will be making phenolic stars and as of yet I dont know. But it seems reasonable that if the star comp is activated by water you would use a water based binder in the prime and for phenolic stars or stars bound with alcohol or acetone a similar binder would be used to prime.

I dont know so hopefully someone will set us straight.

[GermanPyro]

I use only phenolic resin or pvb instead of dextrin, solvent alcohol. Works perfect for me.

[Arthur]

Having read that Phenolic isn't a good binder for charcoal star comps, I'd want to test it thoroughly before committing to use phenolic on BP.

Remember that the BP prime works well in conventional binders as unmilled or much under milled ingredients, NOT as BP, BP is fast enough to flash off without passing fire, BP ingredients are much slower to burn and the silicon powder makes it much hotter so most things ignite with this mix.

[Merlin]

Braddsen has already commented on this in a earlier post.

 

MadMat, I make rather large amounts of stars each year, I would say on a somewhat large scale compared to 'most' hobby pyros. I usually have about 30-40 kilos of cores on hand at all times. For this whole year (starting shortly after last 4th of july, up until now) I have been binding with phenolic. I primarily use the spanish (Jopetes.PDF) star formulas. For me, I have been simply substituting phenolic for red gum at a 1:1 ratio. I don't use hexamine. I don't even keep red gum in my shop anymore. The benefits of binding with phenolic are plentiful. 1) It's cheaper than red gum. 2) When I bind with phenolic, I can throw 8mm cores into the dehydrator right out of the star roller, and in 3 hours I have rock-hard stars, ready to prime and use. 3) Phenolic lowers ignition temperature. 4) You get harder stars than dex bound stars. 5) I use monocapa as one of my primes, so I am able to sub the phenolic for red gum and that gives me a prime that dries in about 5 minutes. One thing to note: It just so happens that all of the spanish colors call for more than 6% red gum, so when I sub phenolic, there is enough to bind with. IF you are using formulas that use less than 6% red gum, then I am not sure what happens. I do know that phenolic is like red gum, in that you can't just use it like dex. You can add dex to any comp without affecting the fuel value, but this is NOT the case with phenolic. For example, I recently tried to bind some charcoal-based stars with phenolic instead of dex. It did NOT work... the stars burned waaaaaay too fast, flew all over the place like go-getters, and were un-usable. Bottom line, binding with phenolic and alcohol has made my star rolling process twice as easy. I could never go back to dex when rolling colors. One thing that I have noticed that is strange, but causes no problems: I can take a phenolic-bound star that is dry and rock hard, prime it with bp, then throw it in the dehydrator.... and within 30 minutes in the heat, the entire star becomes soft again, you can just smash it with your fingers... but then when you let them cool off back to room temp, they become rock hard again. It's strange... it's almost like the phenolic melts again when it gets hot, but hardens when cools.

[redbullzuiper]

Well, Ive just tried it out. I bound my prime with Phenolic resin.

 

It works great. I rolled them in the afternion and this evening they were already rock hard.

 

And to confirm what merlin reposted above, don't throw your phenolic bound stars in a dehydrator or heater. It won't speed up the drying time but instead the stars will get soft and takes ages before they are rock hard. Why dry them in a dehydrator while the solvent is alcohol anyway? It will evaporate. I just place the stars on a sheet and let the alcohol evaporate. After 3 - 4 hours they are rock hard.

[JOPETES]

Hola. Mi experiencia con resina fenolica tipo novolac tratada con hexamina no es positiva en el sentido de que las estrellas quemadan demasiado rapido perdiendo brillo y efectividad. Una estrella de color bien calibrada de 8mm de diametro mas la capa de cebado debe quemar a una velocidad alrededor de 2-2,5seg, dependiendo del color de la estrella.

 

es totalmente cierto que baja el punto de ignicion, motivo por el cual las estrellas que fabrican los chinos encienden a muy altas velocidades. Los chinos deben utilizar alguna resina que quema a una velocidad adecuada pero para eso hay que averiguar qué tipo de resina fenolica es la adecuada y esos datos nunca los revenlan en sus formulas. Actualmente he observado que en muchas empresas que venden productos quimicos para la pirotecnia han incorporado la resina fenolica, ahora es cuestion de comprobar si estas resinas son las adecuadas para composiciones de color.

 

Yo recomiendo utilizar siempre la resina fenolica en la capa de cebado (monocapa) en sustitucion de la red gum para aumentar la efectividad en el encendido de estrellas a altas velocidades sobre todo si se utiliza la tecnica de doble capa (monocapa + bp).

 

se puede sustituir resina fenolica por dextrina en la misma proporcion sin afectar apenas en la velocidad de combustion de la bp. Igualmente se puede sustituir la dextrina por red gum en bp (4% de red gum) pero hay que utilizar alcolol como disolvente.

 

Cuando una estrella con resina fenolica que ha endurecido con alcohol y se calienta a cierta temperatura, la estrella comienza a ablandar debido a que el punto de fusion de la resina fenolica es muy bajo alrededor de 70-100ºc, es dedir, cuando se empieza a calentar la estrella comienza a ablandarse y cuando se enfria vuelve a endurecerse otra vez. Esto ocurre tambien con la goma laca que tiene un punto de fusion de 70-80ºc.

[PhoenixRising]

Muchas gracias Senor Jopetes.

 

Here's what Google translated for me, since I took French in highschool and not Spanish.

 

"Hi. My experience with novolac phenolic resin treated with hexamine is not positive in the sense that the stars burn too fast losing brightness and effectiveness. A well calibrated color star of 8mm in diameter plus the priming layer should burn at a speed around 2-2.5sec, depending on the color of the star.

It is totally true that the point of ignition goes down, which is why the stars that the Chinese make ignite at very high speeds. The Chinese must use some resin that burns at an adequate speed but for that we must find out what kind of phenolic resin is appropriate and these data never resell them in their formulas. I have now observed that in many companies that sell chemical products for pyrotechnics have incorporated the phenolic resin, Now it is a question of checking if these resins are suitable for color compositions.

I recommend always using the phenolic resin in the priming layer (monolayer) in substitution of the gum network to increase the effectiveness in star ignition at high speeds, especially if the double-layer technique is used (monolayer + bp).

Phenolic resin can be substituted by dextrin in the same proportion without affecting barely the rate of combustion of the bp. It is also possible to replace dextrin with red gum in bp (4% of red gum) but it is necessary to use alcolol as solvent.

When a star with phenolic resin that has hardened with alcohol and warms to a certain temperature, the star begins to soften because the melting point of the phenolic resin is very low around 70-100ºc, it is dedir, When it begins to heat the star begins to soften and when it cools it hardens again. This also happens with shellac that has a melting point of 70-80ºc."

 

[starxplor]

When a star with phenolic resin that has hardened with alcohol and warms to a certain temperature, the star begins to soften because the melting point of the phenolic resin is very low around 70-100ºc, it is dedir, When it begins to heat the star begins to soften and when it cools it hardens again. This also happens with shellac that has a melting point of 70-80ºc."

 

To clarify, es is 'it is' and dedir is 'to say', so es dedir is basically 'that is to say'. I am not sure why your translation did not catch the word dedir or that phrase as a whole.

 

Just in case anyone wondered if he was calling the resin some bad name or something, heh.

[JOPETES]

Ok, todo está bien traducido.