braddsn Posted March 24, 2015 Posted March 24, 2015 I would have to agree with Wiley. Because slow flash is KNO3 based, its ignition temp would be lower. In addition to that, I have noticed myself that slow flash ignites a little easier. I treat both types exactly the same safety wise. 1
Sparky68 Posted June 28, 2015 Posted June 28, 2015 Hi, Sorry to resurrect and old post but in the UK potassium perchlorate is harder to source and I like to save it for my coloured stars. So I am looking at KNO3 based salutes (not stupidly big ones but a nice thud).I was looking at this composition below and wondered if it would make good salutes if it was in really strong tubes and was well confined and how it would compare to the typical 7:3 ratio of KClO4 and Al which you can literally pop in a plastic shell with little effort and get a good report. Would it help to mill the KNO3 and S then screen in the Al? Also would coarse Ti have the same results in it as with KClO4 flash? Does it have its merits for making salutes like a very deep tone? Is there a better composition ratio? 50% Potassium Nitrate30% Sulfur20% Aluminium (dark)
Wiley Posted June 29, 2015 Posted June 29, 2015 (edited) That formula works, but not well. The one I have used with good success is: 50 nitrate25 sulfur25 dark Al Your nitrate and sulfur should be as fine as possible. I've never milled them together but I suppose it couldn't hurt. I always screened the two together, then added my Al, diapered it a bit, then passed it through the screen 3 times. If you're not comfortable or familiar with using a screen to mix comps like this, the diaper method still works ok, but screening is quicker and more consistent for larger batches. Please note that the screen is never rubbed or scraped on, especially not with nitrate flash. The comp is placed on the screen, which is then gently shaken, allowing the chemicals to sift through. Mumbles and I have talked about adding 2 percent boric acid to the mix if devices containing it will be stored for a long time. The consensus was that it shouldn't hurt the comp, and it might add a measure of safety. If you want noise, this composition certainly delivers. The first item in this video is 50g in a heavy, spiked container: https://www.youtube.com/watch?v=wuAlnWB458w Thanks to Youtube for ruining the audio. The sound was excellent in person, and the concussion was very noticeable. However, this mix doesn't really need that kind of confinement. 15g in a 1" tube with 1/8" walls, plugged with those wimpy paper plugs produced a startlingly loud report and reduced the tube to confetti. I tried a similar test with an even thinner tube that had the ends closed with one layer of gummed tape, and the results were about the same. Use caution with this and all other flash compositions, as they are all very, very powerful, and in this one's case, fairly sensitive. Edited June 29, 2015 by Wiley
OblivionFall Posted June 29, 2015 Posted June 29, 2015 Hi, Sorry to resurrect and old post but in the UK potassium perchlorate is harder to source and I like to save it for my coloured stars. So I am looking at KNO3 based salutes (not stupidly big ones but a nice thud). I was looking at this composition below and wondered if it would make good salutes if it was in really strong tubes and was well confined and how it would compare to the typical 7:3 ratio of KClO4 and Al which you can literally pop in a plastic shell with little effort and get a good report. Would it help to mill the KNO3 and S then screen in the Al? Also would coarse Ti have the same results in it as with KClO4 flash? Does it have its merits for making salutes like a very deep tone? Is there a better composition ratio? 50% Potassium Nitrate30% Sulfur20% Aluminium (dark) For making Nitrate Flash salutes, you should take a thick-walled tube and put an end disc/cap in and glue that into place with wood glue, then mix sawdust with wood glue until it is a paste and fill the crevice with the paste. This will dry and harden into a very solid end cap and doesn't make shrapnel or a projectile like hot glue does. For the end where your fuse goes in, cut a straw and hot glue it around the fuse so the wood glue from the paste doesn't get the fuse wet. Ti does not affect the sound of salutes in any way, it just makes them a bit more sensitive and make cool sparks that fly everywhere when they explode. Generally 5/3/2 will work but I have heard from several sources that 6/3/1 works better than 5/3/2 in a confined tube.
OblivionFall Posted June 29, 2015 Posted June 29, 2015 That formula works, but not well. The one I have used with good success is: 50 nitrate25 sulfur25 dark Al Your nitrate and sulfur should be as fine as possible. I've never milled them together but I suppose it couldn't hurt. I always screened the two together, then added my Al, diapered it a bit, then passed it through the screen 3 times. If you're not comfortable or familiar with using a screen to mix comps like this, the diaper method still works ok, but screening is quicker and more consistent for larger batches. Please note that the screen is never rubbed or scraped on, especially not with nitrate flash. The comp is placed on the screen, which is then gently shaken, allowing the chemicals to sift through. Mumbles and I have talked about adding 2 percent boric acid to the mix if devices containing it will be stored for a long time. The consensus was that it shouldn't hurt the comp, and it might add a measure of safety. If you want noise, this composition certainly delivers. The first item in this video is 50g in a heavy, spiked container: https://www.youtube.com/watch?v=wuAlnWB458w Thanks to Youtube for ruining the audio. The sound was excellent in person, and the concussion was very noticeable. However, this mix doesn't really need that kind of confinement. 15g in a 1" tube with 1/8" walls, plugged with those wimpy paper plugs produced a startlingly loud report and reduced the tube to confetti. I tried a similar test with an even thinner tube that had the ends closed with one layer of gummed tape, and the results were about the same. Use caution with this and all other flash compositions, as they are all very, very powerful, and in this one's case, fairly sensitive. I have a question, how fast does your KNO3/Al/S burn unconfined? I have tried 5/8" I.D. x 2 1/2" Long 3/32" Wall and 3/4" I.D. x 3 1/2" Long x 1/8" Wall with the paper end plugs glued in with hot glue only to find that the end caps pop out of the salutes. Perhaps I need to use thinner-walled, bigger salutes and use wood glue for the end caps? I am super surprised that your one layer of gummed tape created a boom...
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