r1dermon

as i haven't posted in several months, just an intro. i work in the field of pyrotechnics as both a hobbyist, and a professional. in my occupation, one of the main compounds i come into contact with is flash powder. just a standard binary KClO4:Al flash powder with no adulterants. as probably the majority of you know, this is a pretty dangerous substance if great care is not taken when mixing, storing...etc...so naturally, the industry has introduced a new flash powder product which is supposed to be "safer". of course, "safer" is in the eye of the beholder, and honestly, upon confinement, this new product is just as dangerous as regular flash powder. so here's my question. this product has a trade name, but no information is available on how to make it. several cohort amateur pyro's have reported seeing multiple different flake sizes of aluminum contained within the mixture under microscope. i have scoured the internet for information on this stuff, and what i've come up with, i believe to be an answer/solution. it involves terephthalic acid or pentaerythritol as a primary fuel, KClO4 as an oxidiser, and presumably small quantities of flake Al as a potential catalyst. the product barely burns in the open, unconfined, and still deflagrates violently under confinement. upon my suggestion of these reactants being present in this "new" product, i have been met with much doubt, and reassurance that the actual product is comprised of varying mesh sizes of aluminum. my main questions are, how could i possibly explain the pressure dependant speed of reaction if the mix was simply aluminum and KClO4? how could i tell conventionally, if this product contains either terephthalic acid, or pentaerythritol? how does flash powder actually function? does the aluminum have to reach its melting point in order to decompose? what about the KClO4? do they both need to melt in order to initiate a reaction? thanks in advance. here's a sample video this video apparently shows a mixture of pentaerythritol, KClO4, and a small quantity of aluminum. and here is a video (please skip to 14:13) showing this "trade secret" flash powder substance. is there a scientific explanation as to why this aluminum product functions the way it does, even though it's still just aluminum and KClO4, just like regular flash?

to my best knowledge, thermodynamic stability is a gauge of how readily a compound will reduce to form a product...(correct me if im wrong) kinetic stability on the other hand is a gauge of how much input kinetic energy is required in order to initiate a reaction...(correct me if im wrong) with this in mind, a standard pyrotechnic composition would be extremely thermodynamically unstable, meaning, it reacts vigorously to form products upon reaction...however, since most pyrotechnic compositions require an outside energy source to be initiated, i presume, pyrotechnic compositions would be extremely (or mostly) kinetically stable compounds. with that in mind, to the best of my knowledge, flash powder requires substantially higher temperature than black powder to initiate a reaction. of course, the amount of actual kinetic energy needed to be transferred (i presume) would fully depend on the size of the particles of the reactants. based solely on the higher temperature required for reaction, would that mean that flash powder is actually more kinetically stable than black powder? are there other factors at play which i have not considered? if this is not posted in the correct forum, forgive me...feel free to move it. i wasnt sure if i should post it here, or in the physics forum. thanks.

traditional black powder is often described as containing potassium nitrate as it's primary oxidizer. however, in blasting, there's a different formula which utilizes sodium nitrate. in my experience, sodium nitrate doesn't produce quite as "fast" a propellant as KNO3. one of the major differences is that sodium nitrate is much more hygroscopic, and is easily fouled by humidity. here's my question. in my field (fireworks), sodium nitrate is regarded as inferior. the only reason it's preferred in blasting, is because it does an acceptable job, but for around half the price. im wondering then, why sodium nitrate is actually preferred for smoke producing mixtures? perusing through some mil-spec devices which are designed to emit smoke, i find that sodium nitrate is preferred for producing these effects. pine buff arsenal cites sodium nitrate as the primary oxidizer in their redesigned smoke grenades, and a plethora of smoke producing pyrotechnic formulas already documented, list sodium nitrate as the oxidizer of choice. can anyone shed some insight into this for me?

In my side career, im graced with the opportunity to create some spectacular visual effects. One of these is a fireball. Generally speaking, we can use cremora or naphthalene in powder form, resting on a bed of black powder, and initiated via electronic match from a distance. This produces a decent flame ball. One of the crowd favorites is the petroleum flame ball. The same process is undergone, however the black powder is isolated in an inert container. This produces a very intense effect. Vast quantities of heat are given off, and the ball of flame exhibits a very cool rolling effect. My question being...I've always had success coloring fires with various salts, and im wondering, say i want a green flame, if i introduce barium carbonate to the gasoline, would this color the flame to that end? One industry trick is to bag methanol, along with whatever coloring agent is preferred, and sit that in a large steel pipe on top of black powder. They call this a ghost mine, since the methanol burns relatively clear, it creates a colored flame that you can see through. My intention is to achieve a similar effect, however more intense and not see through. Thanks for your help.

normally, in the industry in which i work (fireworks manufacturing), we're using a mixture of Al, antimony, a very small percentage of sulfur, and a large portion of KClO4 for our salute composition. recently, someone posted a video online about something named "blue" aluminum. as many of you probably know, flash powder is incredibly dangerous to mix and to be around in general...and in the quantities we mix (up to 40lbs through a screen at a time), the results of an accidental reaction due to static or friction, or what have you, would be absolutely catastrophic. well, this "blue" aluminum appears to create the same results as standard flash powder when confined to a container, (plugged tube, or pasted shell...etc...), but in the open, it is practically inflammable. there's barely an indication of any small reaction occuring under the burning presence of a torch. my question is, i've recently discovered that formulas have been created (and patented) which utilize Pentaerythritol as the main fuel, supplemented by a bit of Al, with the same KClO4 as the oxidiser. i've also seen compositions using terephthalic acid as the major fuel source in a binary composition which creates the same results. my major questions are, WHY. why do these compounds react violently when under pressure, but practically not at all, when unconfined, even when mixed with a high powered oxidiser. my second question is, the reaction clearly accelerates exponentially as more pressure is available, so with that in mind, does that mean eventually this compound would produce the same brisance that an HE compound would produce? and lastly, assuming the reaction can be controlled (as far as pressure is concerned), i assume it would be possible to control the tone of the actual "boom" it produces, simply by changing tensile strength characteristics in the vehicle utilized for containment (the mortar shell). thanks for any info.

basically, im trying to determine the force applied to the ground over the area of the bottom of the mortar tube. im not sure if it would be easier to figure for N, or Ns. so lets say an 8" shell weighs in at 7lbs even, and at apogee, gets 800ft above the ground and takes 5 seconds to attain that height. given the information, how would i calculate the net force applied to the mortar? like i say, im pretty "in the dark" so-to-speak, in regards to physics.

hey all, by no means am i a physics major, or professional, but i know a little bit...with that in mind, i was posed a question by a fellow fireworks enthusiast over the weekend. so here goes. basically we're trying to calculate the recoil force of an aerial shell upon launch. there's a second part of the question that might be a little too complex given the information we have, but i'll get to that in a bit. ok, so lets say the shell weighs 100g, and attains a height of 200ft. given that information, what is needed to calculate the force of the shell in motion, as well as the mortar tube it's shot from (given that every action has an equal and opposite reaction). the second part is, upon liftoff, several of these mortar tubes are driven into the ground, lets say a few inches, call it 3. without knowing the density of the ground, is there any way of knowing how much force the ground is actually absorbing, and in effect, robbing from the shell? thanks in advance.

i have some accelerometers that i've tested at sonic speeds (less than 1500fps), which record the Cd as the pressure spikes during the flight. assuming a hypersonic vehicle could be built (it's beyond my capabilities), i have no doubt my electronics could record atmospheric pressure changes, as well as changes in the weight/drag of my rocket in relation to the atmosphere at mach 5, 6, 7...etc...the fastest rocket i feel i could make without failure would be mach 2ish. mach 3 would be pushing it, but hypersonic is out of the question for now. (for me anyway).

like has been stated, this is a very complex question (about the building), without knowing the circumstances. when there's an EXTREME low pressure system hovering right outside of an enclosed house, the house will attain a higher pressure...release that pressure and poof your house implodes...the pressure can be released in any number of ways as well, a tornado throwing a car through the front wall...all the windows simultaneously giving out, the roof getting ripped off by a tornado...etc...once it implodes and breaks apart, it becomes little pieces of debris, and can be tossed around like breadcrumbs. tornado's are truly a masterpiece of natures terrifying beauty. I live in Massachusetts, so unfortunately i've never seen a rateable tornado, of course, most people who have would call that a good thing.

anyone at all? my thought process is that sugar should act as a binder, and as a decent fuel, it shouldn't detract too much impulse, the detergent water is the solvent, so the sugar should harden up the motor once all the detergent water is out of the mixture...and since smokeless powder is a plastic, there should be no problem with dissolving the KNO3 normally found in regular "black powder". any thoughts?

most solutions readily attainable from a pharmacy are 3% conc H2O2 iirc. i'd say whoever said 6% is the highest to go is right on the money...H2O2 is a crazy crazy crazy chemical. (but when experimented with properly, can result in AMAZING reactions...including extremely powerful rocket motors. haha)

it's definitely safe to swish around (dont drink any quantity), as for it's whitening affect, it's tough to say, in such a diluted solution, it probably will have little effect. Just buy the "white strips" for 20 bucks, they last for weeks and work quite amazingly.

I will say that generally, I feel that I was not taught sufficiently in high school. Not 1 physics course, not 1 calculus course, not 1 trigonometry course. I was given a very basic geometry course (geometry is fairly basic anyway), and Algebra 2 was my toughest math course. In-fact, I'd say that Chemistry was my toughest math course really, and even that was a call-in. After high school, I picked up the hobby of advanced amateur rocketry, and I've taught myself more than I learned in 12 years of public education. From physics to trigonometry, fluid dynamics, general mechanical engineering, chemistry, absolutely every one of those topics is REQUIRED to build and fly a rocket and actually KNOW what it's doing. (predicting speed/altitude given the impulse of the motor, the wind, the coefficient of drag) I should be paying 40k a year for the education I've gotten from the almighty Internet. hah.

right, however, surface currents are often driven by trade winds, and ALL currents are affected by the coriolis effect. the same reason a hurricane's path looks like a boomerang.

im trying to cast smokeless powder into a rocket motor (bates grain geometry or maybe just single grain cored geometry). i've come up with one possible solution, and im just looking for input. sugar, detergent, water, nitrocellulose powder. compact into the grain mold, and leave in a curing oven over the course of a few days at 110ish degrees. any insight or other possible solutions?