dave321 Posted March 23, 2020 Posted March 23, 2020 has any one actually got the composition the above are supposed to use to work ? pot chlorate with 1%Manganese dioxide 60Antimony trisulphide 30Aluminium Eckart5413H 10 used with ~2mm (10#) gravel. strangely it just does not seem that sensitive to impact when thrown ?????????
Mumbles Posted March 28, 2020 Posted March 28, 2020 What size of torpedos are you making? Antimony trisulfide sensitizes chlorate more to friction than impact. Maybe they're packed too tight? I don't have much experience with these, so I'm mostly just thinking aloud. Sulfur may also help to get them a bit more sensitive. 1
robbo Posted March 28, 2020 Posted March 28, 2020 Elizabeth over on FW had success, after some effort. It seemed she was rapidly stifled by some others' comments and I didn't see much more about it. There was concern (overblown, I think) about safety (liability?) issues. Pity. If you've access, contact her. 1
robbo Posted March 28, 2020 Posted March 28, 2020 As long as we're on the subject, I've used "adult snaps" as initiators for explosive blowgun darts. Augmented, of course. They worked fine and saved me from working with compositions with which I have no experience. And cheap! Perhaps the same could be done for your endeavor.
dave321 Posted March 29, 2020 Author Posted March 29, 2020 As long as we're on the subject, I've used "adult snaps" as initiators for explosive blowgun darts. Augmented, of course. They worked fine and saved me from working with compositions with which I have no experience. And cheap! Perhaps the same could be done for your endeavor.yes, i know where you are coming from. globe torpedoes were about 1 inch in diameter i believe.maybe there is a critical size / weight needed and ratio of composition to gravel to get them sufficiently sensitive to work,anything below which they wont function ? no i do not have access to Fireworking, who is "Elizabeth"
Mumbles Posted March 30, 2020 Posted March 30, 2020 She's a member here as well. Might want to try reaching out. I don't believe she stops by all that regularly. https://www.amateurpyro.com/forums/user/18487-elisabeth/
robbo Posted March 30, 2020 Posted March 30, 2020 She's a member here as well. Might want to try reaching out. I don't believe she stops by all that regularly. https://www.amateurpyro.com/forums/user/18487-elisabeth/ Thanks, you saved me bugging her through FW.
dave321 Posted March 30, 2020 Author Posted March 30, 2020 She's a member here as well. Might want to try reaching out. I don't believe she stops by all that regularly. https://www.amateurpyro.com/forums/user/18487-elisabeth/thanks have tried to contact her
snapper Posted April 4, 2020 Posted April 4, 2020 I thought the old torpedos where made using phosphorus and constructed in water then assembled wet for safety
dave321 Posted April 4, 2020 Author Posted April 4, 2020 (edited) I thought the old torpedos where made using phosphorus and constructed in water then assembled wet for safety the the current adult throw downs like mandarin crackers or snap bangers, certainly seem to use , i am assuming a chlorate / rp mixture coated onto gravel, and they work well.but i doubt they are as loud as the original globe torpedo type devices, a good thing from a safety point of view. they also have a CE marking Edited April 4, 2020 by dave321
PyroGnome Posted August 20 Posted August 20 (edited) I know this thread is old but if you google Donner's paper on these and some other old impact fireworks, it looks like this was probably the issue: Quote Next, I prepare my chemicals and gravel. The antimony sulfide should be very fine, but is usually available in only 350 mesh or larger. Antimony sulfide can be ground finer by ball milling with steel balls for several days. The potassium chlorate I grind very fine in a mortar and pestle or in a ball mill BY ITSELF. This is the only thing I've seen since I started in pyro that wanted antimony trisulphide to be finer than 350 mesh, usually it's the other direction for the rare formula because people only had the chinese needle / 350 mesh sitting around in general back in the day. The other part that's mentioned a bit later is that the aquarium gravel be quartz. This isn't explained but the primary reasons I could think of are that a) quartz is highly piezoelectric and a hard enough impact might generate a short discharge into the static sensitive mixture and have more to do with initiation than the actual impact itself (like the one from pulling the trigger on one of the barbecue grill lighters or an auto-light propane torch although the torch one isn't easy to spot on the newer models), or b) quartz is far more heavy and dense than many things used for aquarium gravel like the cheaper perlite type stuff allowing more kinetic energy from the throw and more released into the mix on impact, or finally c) chunks of quartz have lots of flat surfaces which increases the chances of things slamming together nicely. If a corner strikes comp between a flat surface and itself it will be transferring the same amount of energy but into a tiny spot. That's how the diamond hammers they've used to crank out all kinds of bizarre forms of water ice under conditions that simulate the surface of gas giants work, mostly. Donner used 5g of mixture for ~12 "excellent" torpedos (he says 200-400mg as the actual measurement) which may be the problem depending on whether you followed Donner's instructions or something else... too little and it may have been spread too thin to set anything but one spot off. Impact sensitivity even for many of the more sensitive mixes can be misleading. Flash mixes with both antimony trisulfide and sulfur in them have a pretty high sensitivity to impact in drop testing but try getting one of them to go off doing something like this instead of the "smack with a steel hammer on the concrete sidewalk" non-test (with the right sidewalk / hammer, you can probably ignite BP that way). Slamming a 2kg brick or metal weight onto something from even a short distance is quite a lot of kinetic energy to try to generate with gravel and even a fairly fast throw unless you're a MLB pitcher. Likewise you'll probably find that mixed in with aquarium gravel to generate what should be a ton of friction along with the impact, nothing is happening. Actual that would be an easy way to test my piezoelectric theory on why quartz was specified, if that's true it should be able to set off regular 67/33 which is the least impact sensitive useful flash mixture (and only 0.1dB quieter) that doesn't involve blue Al (AFN II has some uses outside of hard to ignite flash powder for that, btw. I'll quote it for posterity below if you don't have access) or terepthalic acid but still pretty easy to ignite and sensitive as heck to static. Warning: Off topic. AFN II article on flitters and sinter stars Quote The reason that many of Weingart's flitter mixes don't perform well, and this applies to the Faber mixes for electric stars in Davis as well, has to do with the type of aluminum available. They are all designed to use the "denser, stamped powders favored by the Europeans", as Lancaster says in his book. The aluminum which works best is the nearly impossible-to-obtain German "Blue Head", which is a light pyro, but very dense, like the more familiar black pyro grade. This material, unlike the fluffier American milled powders, resists the heat of the fuel rich compositions, and does not really get going until after it is ejected from the star as molten droplets of aluminum "slag". It is for this reason that many older aluminum mixes are pale and bright, with too little tail effect, since they tend to consume the "bright" aluminum right in the star itself, leaving no residue to "sinter" out and react later with the atmosphere. In the case of the Faber stars, when made with "Blue Head", and a little chlorowax, they actually split into fragments, like a palm tree, before going out. Whether the current Blue Al is the same thing as the german Bluehead is beyond my knowledge. Edited August 20 by PyroGnome
Mumbles Posted August 23 Posted August 23 "Bluehead" and blue aluminum are not the same. Blue head, black head, yellow head, etc. are all sort of colloquial terms that refer to the color of the head on the drum when supplied by the manufacturer (Eckart or a previous iteration usually). These are all stamp milled flake aluminums. All indications I've seen of "Blue aluminum" is that is an atomized variety. Some previous analysis has found that it contains some finer particle size component compared to something like Alcoa 120 or something else more typically available as atomized that people may be more familiar with for glitters.
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