Soloserly Posted March 25 Posted March 25 On 11/4/2023 at 9:06 AM, pyrogenius007 said: The composition of the D.E is Bismuth Trioxide 71, Black copper Oxide 14, Mg.al. 10, Fine atomized aluminum ( -300 mesh) 5. This was mixed with 10% N.C. dissolved in acetone... I know this is an older thread now, but I thought I'd mention something that hasn't been considered. I while ago I wetted some dragon eggs prior to making dragon flower stars and noticed that they heated up a lot, just from contact with the water. I let them dry and they no longer crackled, but still gave some pretty sparks. For the next batch I waterproofed the dragon eggs by spraying them with diluted NC Laquer and they didn't heat up when wetted and the stars worked well. This can happen even with K2Cr2O7 added. It reminded me of a time when I first started rolling stars and I put some chopped aluminum foil in a blender outside and blended it with some water. It got hotter and hotter until it boiled and steam poured out and I ended up with a pile of inflammible aluminum oxide. I think sometimes issues we blame on primes or processes are actually issues with the oxidizing reaction of water on aluminum or magnalium
Zumber Posted March 25 Posted March 25 3 hours ago, Soloserly said: I know this is an older thread now, but I thought I'd mention something that hasn't been considered. I while ago I wetted some dragon eggs prior to making dragon flower stars and noticed that they heated up a lot, just from contact with the water. I let them dry and they no longer crackled, but still gave some pretty sparks. For the next batch I waterproofed the dragon eggs by spraying them with diluted NC Laquer and they didn't heat up when wetted and the stars worked well. This can happen even with K2Cr2O7 added. It reminded me of a time when I first started rolling stars and I put some chopped aluminum foil in a blender outside and blended it with some water. It got hotter and hotter until it boiled and steam poured out and I ended up with a pile of inflammible aluminum oxide. I think sometimes issues we blame on primes or processes are actually issues with the oxidizing reaction of water on aluminum or magnalium Yeah Crackling stars are extremely sensitive against water. Aluminium is also extremely reactive it instantly reacts with air and form s aluminium oxide coating around its particals this oxide coating prevents aluminium from further reaction with air. As soon as this oxide coating brakes , aluminium reacts further with water or oxygen. While manufacturing aluminium stearin is added this stearin coating acts as a barrier between aluminium and water and helps to stop aluminium water reaction. 1 to 2 percent Boric acid is added to prevent aluminium nitrate reaction in presense of water. Boric acid streangthen aluminium oxide coating and helps to stop formation of ammonia.
Soloserly Posted March 30 Posted March 30 On 3/25/2024 at 1:06 AM, Zumber said: Yeah Crackling stars are extremely sensitive against water. Aluminium is also extremely reactive it instantly reacts with air and form s aluminium oxide coating around its particals this oxide coating prevents aluminium from further reaction with air. As soon as this oxide coating brakes , aluminium reacts further with water or oxygen. While manufacturing aluminium stearin is added this stearin coating acts as a barrier between aluminium and water and helps to stop aluminium water reaction. 1 to 2 percent Boric acid is added to prevent aluminium nitrate reaction in presense of water. Boric acid streangthen aluminium oxide coating and helps to stop formation of ammonia. When I was learning to TIG weld aluminum, I could never get the arc to start without burning through because the welder wouldn't break through the oxide layer, even though I cleaned it with sandpaper and used high-frequency arc initiation to break up the surface oxides. Finally I asked the instructor what I was doing wrong and he said, "Stop cleaning it with aluminum oxide sandpaper." My next weld was successful. 😆
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