Skullbomb177 Posted November 13 Posted November 13 Hello pyros, Ive got a question. I was making a multieffect preburner. Red smoke to white strobe (bleser). The red smoke composition i am using from smoke tubes i bought online. I was wetting the smoke composition a bit to much, so when i testing them they only burn. So my question is, how long pyrotechnician composition needs to dry, when they already pressed inside a tube?
PyroGnome Posted November 13 Posted November 13 Usually when anything is pressed in tubes wet, it's extremely small percent of water (think mist) and used for rockets and similar without metal powders where the water slightly enhances the burn speed up to a point. Even if it does dry, if there's too much water or it's pressed too heavily, you'll end up with material from the center trying to ooze out of the exposed surfaces. Too much water will soak into the sides of the tube and weaken it. I accidentally pressed some crossettes too highly this summer and they took two months to dry, with new patches of sticky black SGRS + comp mix appearing in tarry bubbles on the surface through the whole process. They were pressed so hard they didn't lose integrity or crack and are still usable at least.
Kalifireworks Posted November 13 Posted November 13 Have fun igniting Strobe (high igniton point) with a smoke comp (very low temp burning)
Carbon796 Posted November 14 Posted November 14 21 hours ago, PyroGnome said: Usually when anything is pressed in tubes wet, it's extremely small percent of water (think mist) and used for rockets and similar without metal powders where the water slightly enhances the burn speed up to a point. Even if it does dry, if there's too much water or it's pressed too heavily, you'll end up with material from the center trying to ooze out of the exposed surfaces. Too much water will soak into the sides of the tube and weaken it. I accidentally pressed some crossettes too highly this summer and they took two months to dry, with new patches of sticky black SGRS + comp mix appearing in tarry bubbles on the surface through the whole process. They were pressed so hard they didn't lose integrity or crack and are still usable at least. That sounds like they were far too wet. And not properly tempered/screened once the water was added. More than over pressed. SGRS takes far longer to fully activate than Dex. For a given amount of water. If you also replace Dex 1 to 1 with SGRS that will accentuate the effect.
PyroGnome Posted November 17 Posted November 17 Thanks for the advice. I did compensate for SGRS amount since the original formula called for dex, but not for the increased activation time... "crumbly, barely holds together" without the binder activated probably turned into "dough" when it was some hours later after they were already pressed. I'll let it sit longer next time I use SGRS for something pumped. Back on the original topic, I missed the "smoke comp from tubes online" thing although I should have caught the mixture combination. I don't know if commercial smokes are chlorate based; I could see those being such a low-energy mixture that it isn't considered dangerous (unless you disassemble it then do something additionally silly like wetting it with water when half the mix is a solvent dye or disperse dye, neither of which is soluble in water to effectively separate it into parts then dump it onto a sulfur containing composition that's designed to operate in a sort of edge-of-exploding state as is), being a ~20% sulfur / ~20% MgAl comp with two nitrate oxidizers you should probably not be combining these two in the same tube. Of course it might not be chlorate. The question is what it actually is and whether you know or not. Before worrying about how much to wet things you should be more concerned that they probably aren't meant to be wetted and pressed that way and instead consolidated with a hydraulic press and if they're wetted at all it's in advance, with something the dye is actually soluble in, to homogenize and produce grains that can be pressed without dust going everywhere. You should probably look into the basic compatibility issues and safety too and make your own smoke mix despite the questionably higher cost for something of that scale so you know it's compatible and can work out a way to transition from smoke to strobe igniter that won't explode, and so you don't decide it might look better with red smoke and the red strobe one day and try to dump wet chlorate smoke mix on top of AP strobe mix after which they'll be identifying you from dental records based on teeth found embedded 1" deep into the hardwood of the neighbor's back porch... Sorry to be so grim but this isn't a hobby to blindly screw around with, some areas more than others, and this is one of them. Especially if "preburner" means the thing I think it means on top of the other issues.
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