TXpyro Posted March 31 Share Posted March 31 I made some sparklers with Alpha Chemicals "5 micron aluminum powder" and I was wondering what I could compare it to based on the photo below. Alpha Chemicals is not very specific on the specs. Anyway, this is the ratio I used: 44.4 Potassium Perchlorate 44.4 Aluminum (unsure the kind) 11.2 Dextrin I'm just not sure what kind of aluminum is most comparable. Maybe flake or spherical aluminum? I'm not really sure. I just don't want to accidentally make flash powder. Also, the orange sparks are from the steel wire burning, not the composition. Link to comment Share on other sites More sharing options...
Richtee Posted March 31 Share Posted March 31 I dunno how to judge the type of AL from that. But... those going BOOM are unlikely with that high a fuel ratio. Not to mention the dex content. Man- they are BRIGHT! Link to comment Share on other sites More sharing options...
Zumber Posted March 31 Share Posted March 31 Flake aluminium has sharp edges/corners that easily ignited which makes it reactive. Spherical aluminium have no sharp edges which makes it less reactive than flake aluminium. In our Country for sparkler oxidizer is barium nitrate and potassium nitrate with different meshes aluminium powder combinations fine aluminium is less and coarser is more. For center wire copper wire is used and it is coated with some powder( dont know) before applying sparkler coating so that it holds sparkler composition and prevent paste from falling apart when sparkler is wet. Potassium perchlorate is powderful oxidizer and makes mixture energatic if alumiuium is in finer form. Link to comment Share on other sites More sharing options...
taiwanluthiers Posted April 14 Share Posted April 14 (edited) You want spherical aluminum, around 325 mesh will do. 5 micron is like 1500 mesh or something, that's pretty fine. You want something in the 40 micron range. That mixture of potassium perchlorate and aluminum isn't exactly flash powder, but the 5 micron makes it pretty darn close (if ignited in loose powder without binder, it may well behave like it). Spherical matters because it will burn slower. Yours burn so bright and hot because of the small particle size. Also add some iron filing to it to make it spark, or titanium powder. Honestly I kinda stopped getting excited about sparklers, especially when I took up welding. Stick welding electrodes burn almost like sparkler when you strike an arc, except you're sticking metal together in the meantime. Edited April 14 by taiwanluthiers Link to comment Share on other sites More sharing options...
Mumbles Posted April 23 Share Posted April 23 Mesh stops having a lot of meaning at a certain level. A wire screen becomes way more wire than opening eventually. The particle shape of what you have is probably atomized, but can be determined fairly easily by looking at it. Flake is almost certainly going to be coated with a fatty acid at this particle size, and will smell like crayons. It's needed to keep it from welding back together while flattening and reducing the particle size. It will also be pretty fluffy. Atomized will be darker grey, probably not smell like crayons, and be denser or more compact most of the time. They also flow differently, but that is harder to describe. Let me know if this doesn't help you get an answer, and I'll give it a shot though. Link to comment Share on other sites More sharing options...
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