BP question, lift and break

[braddsn]

Ok so, when we talk about coating rice hulls with bp for break... I plan on using my star roller for this. Moistening the rice hulls and rolling bp onto them. My question is... when I mill the bp... should I add 5% dextrin so that it will bind better to hulls? Or just use straight mill dust on the hulls? ANd for lift.... just straight bp mill "dust"? I have read in some articles about "granulating". I just want to know what gives you guys the best performance for break and lift. I know some of this will just be opinion based... I just want some experience-related opinions. Thanks!

[TYRONEEZEKIEL]

I think you may be unclear on some of the terms.

 

Mill dust is useless right out of the mill. It will not burn well enough to do anything as is. You have to either granulated it, corn it, or coat it.

 

For coating hulls you can mill it with or without the dextrin. If you don't mill with Dex, you will have to screen it in later which is a pain. I suggest milling it with dextrin then coating the rice hulls with that.

 

For starting the hulls, you need to soak them in Hot water for about 20 mins and drain them before you coat them. Skylighter has a fantastic tutorial.

[pyrokid]

I use dextrin when I make rice hulls. I don't roll them though. I soak the hulls in water, drain them, then dust comp on in increments of 20% of the total amount of BP being used. The mixing is done in a Ziploc bag.

 

It is mandatory that lift charge be granulated or corned. The interstices between powder granules allow flame to propagate faster in the mass of composition, which is something that doesn't happen with raw powder. Those on the forefront of pyro development have all kinds of techniques for granulation, but starting with hot BP, all I ever needed was room temperature water and 3% - 5% dextrin in the comp. Granulate through aluminum window screen.

[Jordan]

Granulating can be achieved with only 2% dextrin. Most people do not go this low until they really want to maximize their BP speed. Using 10-25% alcohol in your dampening mix wouldn't hurt either, it helps to break surface tension and really combine the chems and dissolve the KNO3.

[TYRONEEZEKIEL]

For the hottest, most powerful BP, granulating with denatured alcohol with no binder is the way to go. Even just a few percent binder is enough to slow it down. In any case, the increase of surface area and grain strength is what we need to make BP useful

[Bobosan]

I roll BP on rice hulls. 3oz of rice hulls and 15oz of 75/15/10 paulownia +1-2% dextrin, a 5:1 ratio The BP is milled with the dex. Sieve the small crap out of the dry rice hulls with a 20 mesh screen. I boil enough water to completely cover the hulls in a bowl. After 5-10 minutes of stirring the hulls, the "floaters" will be removed from the water surface. After draining the soaked hulls, they are put into a bag made from fiberglass screen and run through the spin cycle in the washing machine. They are dumped into the roller and BP is added with additional wetting, if needed, from a spritzer until all 15oz of BP is consumed onto the hulls.

 

 

http://youtu.be/0mOUB9JD0TQ

 

Edited August 17, 2014 by Bobosan

[schroedinger]

Also if you don't want to presoak you hulls, have look at the toro method, works like a charm, just make sure to tumble the hulls with your hands sometimes

[MrB]

Sieve the small crap out of the dry rice hulls with a 20 mesh screen. I boil enough water to completely cover the hulls in a bowl. After 5-10 minutes of stirring the hulls, the "floaters" will be removed from the water surface.

Sifting the rice hulls is a good idea, it provides more uniform rice hulls for making the break charge. I'm not covinced boiling the water makes any difference, hot or cold, it just soaks in anyway. Perhaps it's faster if it's boiling hot, but in that case, boiling a lot of water, and dumping the rice hulls in to the boiling water and stirring it would seam like the better idea. It just seams like adding effort that isn't really providing a benefit. Am i missing something here?

 

Floaters are most likely just like everything else, they just have an air bubble stuck on, or inside them. I'm not sure removing them is doing anything useful.

 

Personally i soak rice-hulls in a bucket of cold water, after rinsing it of a couple of times. No screening, just rinsing and splashing it around to get rid of any dust particles. Soaking is done for no less then an hour, often over night. I'm sure it could soak a lot less, but i'm not in a habit of stressing out, and doing things in a rushed fashion, so i set a bucket with rice-hulls up as i start the projects i'll need em for. Once i'm done soaking, i use a screening cloth originally used for air filtration, and just pour the stuff in to it. (It's much like whats in the clothes dryer, with slightly larger mesh) Spin it around for half a minute-minute, and it's darn near perfect for use in a bucket-roller. I use a 4-5.5:1 ratio of the hottest BP i can make, to coat the hulls, when it goes dry i pretty much just let it spin for a while longer, and it wet's through, and i can add the rest. If i have to spray it, then i spun it for to long and removed to much water. If it looks to wet i add more BP, i want to avoid "polishing" the surface, so they should end up slightly damp, but not wet on the outside, which leaves a good texture, and makes sure they ignite easily. (And hence the 4-5.5:1 ratio. I measure up the 4:1 ratio in a paper cup, and make a not of how much is needed for 5.5:1. If it looks TO wet at the point when i've added the first cup, i spread it out on a drying screen, and leave it for a while, so i can get back to it later. Depending on the size of the shell i'm using it for, i aim for a higher or lower ratio. Smaller shell, higher ratio.)

 

Toro works great for stars, but i have a consistency problem, where my stars become all weird sizes, and some are slightly out of shape. Blaming the roller shape, but i haven't been able to track down the ideal bowl yet.

B!

[Bobosan]

B, I've always had this penchant to use hot water for everything H2O pyro related. I use it when preparing BP for granulation too. It may be an unnecessary step but it just "feels" right to me and the results are successful. Ever notice the heat generated when mixing a batch of 75/25 water/denatured alcohol? It seems to help with rolled star formation much easier than a cooled aqueous solution.

 

From my experience the rice hull "floaters" are small leaves and stems and the real hulls sink, especially after stirring. I've coated the junk before but uniformity is lost. The amount that floats is not all that great but again, it just feels and looks right to get rid of them.

 

Try hot water next time and see if that improves your rice hull soak time. I don't put the hulls into the water, I put the water into a large bowl that is holding the sieved hulls.

[MrB]

I'll try it, but i'm quite certain the water will be cold by the time i get around to doing anything with the hulls :- )

 

Leafs and stems... I don't have any (At least none that i find) of that stuff in my hulls. If i were to find something to complain about, then it's the dust. I get my hulls from a beer brewing supply. It's about 2 bucks to the kilo as opposed to about 10 bucks / kilo from the "pyro" supplier. I never tried the pyro stuff, to me it was a nobrainer, at least around here, one pretty much has to be insane to go with the pyro stuff. I always figured the "pyro" stuff would be the same, pretty much. If anything, less dusty.

Shipping is cheaper to, so i don't have to buy as much, and keep in storage. Always a (HUGE) bonus. Got enough bulk packages taking up space in my storage unit as it is.

 

B!

[braddsn]

Thanks guys for the great info!! Awesome!