Pirotecnia Posted April 18, 2012 Posted April 18, 2012 Flash Powder made with Potassium Nitrate, Aluminium and Sulphur is safer than the other types of Flash?
dagabu Posted April 18, 2012 Posted April 18, 2012 Flash Powder made with Potassium Nitrate, Aluminium and Sulphur is safer than the other types of Flash? "Safer" isn't really part of the dialog here but it certainly is less prone to ignition then Perc and does not detonate in a pile like Perc flash. I have heard it referred to as slow flash and is used as a booster, has a little more "thump" then BP in a report and can be dusted on BP coated rice hulls in shells but I wont say it is safer. -dag
Tanner808 Posted April 18, 2012 Posted April 18, 2012 What exactly would and does it do as a booster on rice hulls and how much would u add And In reports it does make a very deep boom
Bcorso85 Posted April 19, 2012 Posted April 19, 2012 I've read just the opposite. No flash is safe as mentioned above. And shouldn't be played with at all. Its deflagation....know I spelt that wrong....is so fast its considered a high explosive. Sulfur is a catalyst and fuel. So the sensitivity is increased...a lot. I am not exactly an expert, but i dont think there is any reason to add sulfur to a flash. I believe nitrate based flash is much more unstable in the presence of moisture. Which can be humidity, sweat drops, and pressure. Remember when you close and seal that shell you are creating a pressure. And remember, what happens is you press to hard and the friction causes an accidental ignition?.... in your hands. If your making a three inch shell, there is a great video on you tube by Ned Gorski showing different bust charges. The boosted shells blew some of the stars blind, and made the break uneven. Some hot b.p. was the best break on the shells. And to answer your question I like just a dusting on the rice hulls before I seal the shell, just like Dag said, but a slow flash, not a dark metal. Sorry if my post steps on any toes, just wanted the safety information I know to be passed on.Ben
dagabu Posted April 19, 2012 Posted April 19, 2012 I've read just the opposite. No flash is safe as mentioned above. And shouldn't be played with at all. Its deflagation....know I spelt that wrong....is so fast its considered a high explosive. Sulfur is a catalyst and fuel. So the sensitivity is increased...a lot. I am not exactly an expert, but i dont think there is any reason to add sulfur to a flash. I believe nitrate based flash is much more unstable in the presence of moisture. Which can be humidity, sweat drops, and pressure. Remember when you close and seal that shell you are creating a pressure. And remember, what happens is you press to hard and the friction causes an accidental ignition?.... in your hands. If your making a three inch shell, there is a great video on you tube by Ned Gorski showing different bust charges. The boosted shells blew some of the stars blind, and made the break uneven. Some hot b.p. was the best break on the shells. And to answer your question I like just a dusting on the rice hulls before I seal the shell, just like Dag said, but a slow flash, not a dark metal. Sorry if my post steps on any toes, just wanted the safety information I know to be passed on.Ben Ben, Slow Flash -or- KNO3/Al/S is not more unstable in the presence of moisture anymore then any comp bound with an aqueous binder. It is also not pressure sensitive as this comp is the base for many effects and delays in rockets. I have pressed it to 12,000LPI and beyond with no effect. There are perhaps, hundreds of comps from gerbs to fountains to stars that have various combinations of KNO3/Al/S are are bound with a water based binder. I have had one batch of D-1 get really hot on me that I had to spread out onto cardboard to cool but other then that I have never seen these chems become unstable. -dag
Mumbles Posted April 20, 2012 Posted April 20, 2012 I would have to agree with BCorso here. It probably is more unstable to moisture than perc and analogous aluminum, but that does not necessarily mean you'll have a problem. I personally have never had a problem with nitrate/Al reactions unless there was a base present. Even then it was only once. It's only happened to me in a composition containing KNO3, Bright flake Al, and sodium oxalate. I've heard of others having problems too, but the general similarity is that every mention of this I've seen almost invariably involved a base in the composition as well. If it makes you feel better, you can add a percent or two of boric acid to the slow flash. Sulfur most certainly make flash powders more sensitive, and lowers ignition temperature. I don't have any real world data on sensitivity of these slow flash powders, or anything though to say if there is an increased safety concern.
Bcorso85 Posted April 20, 2012 Posted April 20, 2012 I hope I never have a heat up on me. I partially agree with you dagg, but for safety and performance concerns, I ball mill everything but the aluminum, then add the aluminum to a black powder comp; much like making veline and adding the magnalium after its all mixed. So you again, don't make a flash. Which ever may be best for our personal taste. The point I wanted to make is if you don't know how much flash to add to a small shell, then you shouldn't be adding it at all. Or making it for that matter.Ben 1
FlaMtnBkr Posted April 20, 2012 Posted April 20, 2012 I don't think I would know off the top of my head how much flash to add as a booster to a shell, especially slow flash. I don't think that means I have no reason to make it. No one knows everything so I would research a starting point and experiment with how much to use for the size shell I'm making and the stars I'm using since different stars take fire better than others. And I also think there is a place for sulfur in certain flash. It is in the slow flash formula because it probably wouldn't light reliably without it. When using less reactive aluminum, adding sulfur can again allow the flash light reliably. I have cut expensive dark aluminum with cheap spherical or bright flake for use in aerial salutes. With just the mix of aluminum they didn't light reliably or just made a flash of light and no noise. Adding sulfur made them reliable. Also, adding a tablespoon or so of coarser BP also just about guarantees ignition. If using modern acid free sulfur there shouldn't be a problem. No, someone new to pyro probably shouldn't be playing with flash at all. But the truth is, flash has probably gotten the bulk of hobbyists involved in pyro more than other avenues. There are also formulas using chlorates and sulfur that make me cringe, and they have been used for a long time by pros. Doesn't mean everyone should be trying them, but it does mean with special care it can be done without incident. This isn't meant to encourage people to do dangerous things, just to show the other side of the coin. 1
Bcorso85 Posted June 6, 2012 Posted June 6, 2012 Since this topic is up,I now have a question, let's take a slow flash break. The other day I was lighting off come commercial HD Shells and Big Fireworks brand 60 gram canister shells. They have to be broken with a slow flash with that sound and size break., a slow flash composed of potassium nitrate, aluminum flake, and Antinomy or sulfur. Or something that doesn't produce a brilliant flash. If I wanted d to coat rice hulls with this composition, would boric acid be necessary, and what ratio is recommended for a small shell?I understand the sensitivity of this conversation. If someone wanted to message me a reply please do. Ben
MetalNeko Posted March 17, 2015 Posted March 17, 2015 "Safer" isn't really part of the dialog here but it certainly is less prone to ignition then Perc and does not detonate in a pile like Perc flash. I have heard it referred to as slow flash and is used as a booster, has a little more "thump" then BP in a report and can be dusted on BP coated rice hulls in shells but I wont say it is safer. -dagSorry for bringing up an old topic, but usually someone mentions this and I didn't see it posted;Keep in mind, flash powders do not "detonate" but rather they deflagrate (like black powder and other low-explosives). While it may not seem like an important detail to pyrotechnicians working with low explosives, it does determine how confinement effects them. When a substance deflagrates, it favours stronger confinement for a more powerful burst. When using sulfur in mixes containing metals, can the presence of moisture sometimes form sulfuric acid and then catalyze the oxidation of the metal?
Sparx88 Posted March 18, 2015 Posted March 18, 2015 Well sure, it can but with most of todays sulfur we can get it's fairly low. Not like we want to be making this stuff and storing it. Theres a few here that will explain better coming up.
FlaMtnBkr Posted March 18, 2015 Posted March 18, 2015 With low acid sulfur and no water being added it isn't an issue. But I think flowers of sulfur can contain some acid and should be avoided. However, it has been suggested that nitrate based flash with sulfur has a lower ignition temp than perchlorate flash and is actually easier to ignite with heat/flame.
braddsn Posted March 18, 2015 Posted March 18, 2015 For those interested, slow flash adds a nice extra thump to shell breaks if you take 3 percent of total weight of burst, then add that amount of slow flash. Ie... if you have a container with 1000g of burst, dust the whole batch with 30g of slow flash, mix it up good,(dry) and you will have burst on steroids. As for safety, I treat all flash the same. I wear full ppe (for me, welding attire) and only mix small amounts at a time.
Wiley Posted March 18, 2015 Posted March 18, 2015 And it gives a pretty good bounce if you put 30g or more in a bottom shot/thick-walled salute
Floridapyro Posted March 18, 2015 Posted March 18, 2015 Curious what method people use for can shells. I've only used whistle as my booster. I am building shells to shoot in two weeks and want to try the slow booster. All my shells will be 3" can's. Obviously my burst will be added via canulle.
FlaMtnBkr Posted March 18, 2015 Posted March 18, 2015 You can try just dusting your burst with dark flash grade aluminum. Just enough to cover it all but not pile up in the bottom though it won't hurt anything but waste aluminum. You don't have to mix flash and it helps boost the burst and give it a nice thump. Might be worth experimenting with if you don't want to mess with flash. 1
Floridapyro Posted March 18, 2015 Posted March 18, 2015 I'm not too concerned about thump, just a good spread. I'm okay messing with f, I treat it with all due respect.
BurritoBandito Posted March 18, 2015 Posted March 18, 2015 With low acid sulfur and no water being added it isn't an issue. But I think flowers of sulfur can contain some acid and should be avoided.However, it has been suggested that nitrate based flash with sulfur has a lower ignition temp than perchlorate flash and is actually easier to ignite with heat/flame.Apparently, modern flowers of sulfur is (are?) actually low acid. Modern flowers of sulfur are made from approximately the same quality of sulfur as the "sulfur flour" we use in pyro.It is not the highly acid stuff of past years, where it was collected from sublimation and condensation apparatus (lately), and originally from fumaroles and other volcanic features, in its native, high-acid state.
nater Posted March 18, 2015 Posted March 18, 2015 Curious what method people use for can shells. I've only used whistle as my booster. I am building shells to shoot in two weeks and want to try the slow booster. All my shells will be 3" can's. Obviously my burst will be added via canulle.I just use hot BP in cylinder shells. Some builders have the theory that boosting your burst makes it more likely for the spolette on the bottom shot or next break fail to catch fire causing a dud. When I make a traditional rocket header or ball shell, I typically use whistle as a booster since I almost always have some in storage for rockets and it does not burn with the distracting light of flash powder.
schroedinger Posted March 18, 2015 Posted March 18, 2015 For 3" Corned 2 FA bp works good. If it is a single break it is no problem to add some flash booster if necessary.If you just stack one layer of about up to 10 mm pumped stars around the wall, H3 4:1 on hulls work great.
Shunt Posted March 19, 2015 Posted March 19, 2015 I just use hot BP in cylinder shells. Some builders have the theory that boosting your burst makes it more likely for the spolette on the bottom shot or next break fail to catch fire causing a dud. When I make a traditional rocket header or ball shell, I typically use whistle as a booster since I almost always have some in storage for rockets and it does not burn with the distracting light of flash powder. I agree with nater. I do not like working with fine AL flake. It is expensive, gets all over everything, even working outdoors in the best of low wind/high humidity environments, seems to be too much of a mess to clean from my work area, and it does not naturally decompose like a light dusting of whistle will do with time. AL is a METAL, not a chemical, and will linger on and on in my work area and me everytime I go there and the winds whip it around and around again. Whistle just seems to me as an alternative that is not as toxic to my body and the environment, but must be treated with the same respect as 70/30.
Carbon796 Posted March 21, 2015 Posted March 21, 2015 Curious what method people use for can shells. I've only used whistle as my booster. I am building shells to shoot in two weeks and want to try the slow booster. All my shells will be 3" can's. Obviously my burst will be added via canulle.If your making 3" cylinder shells. I would probably start at 2-3 grams of a SFB. Your BP, string, and paper. Are all variables that can effect your burst strength.
Wiley Posted March 21, 2015 Posted March 21, 2015 Personally, I'd try using just BP for burst the first few times. That's the way it's done in Fulcanelli, and it can yield very nice breaks if done correctly. I know Old Glory Powder Co. uses pulverone (non-ball milled, granulated BP, ordinarily used as a "filler") and their shells look quite nice.
Ubehage Posted March 24, 2015 Posted March 24, 2015 KNO3-flash is not as unstable as Perch-based flash. And it also burns considerable slower.But it still is flash. And remember that KNO3+Sulphur reacts with moist, and decomposes the Aluminum.Remember to stabilize that reaction with Boric Acid.
Wiley Posted March 24, 2015 Posted March 24, 2015 KNO3-flash is not as unstable as Perch-based flash. And it also burns considerable slower.But it still is flash. And remember that KNO3+Sulphur reacts with moist, and decomposes the Aluminum.Remember to stabilize that reaction with Boric Acid.I'm not sure I agree with that first statement. In my experience, KNO3 based flash is much more sensitive to impact and ignites more easily than perc based flash.
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