hst45 Posted January 20, 2012 Posted January 20, 2012 (edited) Poorly shot video of a pretty decent shell. The rising comet burned out before apogee so I missed the break, but the break, spread and color saturation were pretty good. While I'm at it here's another one. Better video, but...well.....you'll see. Edited January 20, 2012 by hst45
Sabdacrab Posted January 20, 2012 Posted January 20, 2012 Poorly shot video of a pretty decent shell. The rising comet burned out before apogee so I missed the break, but the break, spread and color saturation were pretty good. While I'm at it here's another one. Better video, but...well.....you'll see. Wow, nice blue! What composition was it and what size where the stars? Thanks, Sebastian.
Potassiumchlorate Posted January 21, 2012 Posted January 21, 2012 Nice. You seem to have very "hot" BP too. Especially the first muzzleflame is gigantic for a 3".
hst45 Posted January 21, 2012 Author Posted January 21, 2012 The comp. was: 68% Ammonium Perchlorate17% Copper (II) Oxide15% hexaminebound with shellac They were cut stars aproximately 1/4". First layer prime was Hardt #6, second layer fencepost prime, then dusted with BP meal. @ Potassiumchlorate: I tend to over lift my shells. These usually weigh-in at between 130 and 140 grams and I use 14 grams of lift. @ Karlos: I assume you mean too much break on the red shell. Yup, you're spot-on. See comment in description on Youtube; "Think you used enough dynamite there Butch?" I switched from whistle break to 70/30 and made a SLIGHT miscalculation...O.k., I blew the thing all to hell. I found it amusing none the less.
Potassiumchlorate Posted January 21, 2012 Posted January 21, 2012 For 3" I use 10% as well. For bigger shells I use 6-7%. Interesting composition, though I prefer a bit brighter blues with a touch of green myself. Hardt 6# is nasty but very good for igniting AP stars. Don't you find it hard to bind with shellac? Do you use solution or pulverized?
Mumbles Posted January 22, 2012 Posted January 22, 2012 I've often wondered about prime #6 that Hardt gives. Its essentially Shimizu's red thermit prime added to a cooler prime. It may be possible to mix meal powder 80:20 or 70:30 with something like iron oxide:Al thermite.
hst45 Posted January 22, 2012 Author Posted January 22, 2012 Don't you find it hard to bind with shellac? Do you use solution or pulverized?I used liquid shellac. That pretty much necessitated making cut stars as I wasn't up to try rolling them. I wetted the compound with shellac, screeded it to about 1/4" to 5/16", cut these into strips and let them dry. The next day I cut them to length using an anvil "pruner." Mumbles, if I'm tracking you thought process, your thermite prime would be substituting molten iron for the molten lead from the lead tetraoxide in the prime, correct? Since that would be much hotter than the lead it certainly should carry sufficient heat to light these and it would get rid of the toxic lead issue.
Mumbles Posted January 22, 2012 Posted January 22, 2012 Yep, molten iron. The prime as given probably is more designed to make molten SiO2 than molten lead. Looking at the chemistry, it looks like you might be able to substitute in iron, copper, or bismuth oxides for the lead content to maintain that molten SiO2. I don't know how well it'd work, I was really just thinking out loud.
Potassiumchlorate Posted April 21, 2012 Posted April 21, 2012 I tried a few stars with this comp using red gum as a binder. The video doesn't make it justice. With red gum the comp is: Ammonium perchlorate 64Copper(II)oxide 16Hexamine 14Red gum 6 I have had problems with binding it, though. The stars are a bit brittle. I think the hexamine is to blame, although it seems perfectly dry and even partly airfloat. With red gum the stars burn incredibly fast with a big bright blue flame.
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