flying fish Posted August 31, 2007 Posted August 31, 2007 Recently I ordered a bunch of crap from skylighter, and now I'm trying to figure out what to do with it all. I had heard that lactose could be substituted for hexamine in most blue star forumula's, and as lactose was cheaper, I ordered a pound of that instead of hexamine. I had Euter' s Blue in mind: Ammonium Perchlorate: 70Cu Powder 15Hexamine 15Shellac 2-5% I used Lactose in place of the Hexamine, and bound it with NC laquer instead of shellac in alcohol. The stars burned a nice blue on the ground... but shot from a tube they just spray orange sparks with no hint of blue. Right now I'm thinking that the stars spray firedust because they are not held together well enough or maybe burn to fast. But decreasing the amount of AP and increasing the other chemicals still exhibits the same problem! Some of the things I thought I would experiment with are adjusting the ratios further, different binders, and adding a burn inhibitor (perhaps barium carbonate) or something else to prevent the star from spreading. I thought I'd ask you guys for advice before I get too far on my wild [blue] goose chase. If you have any ideas, I appreciate them!
Mumbles Posted August 31, 2007 Posted August 31, 2007 Barium carbonate will without a doubt wash out the color. If you're going to add any burn rate inhibitors, add a chlorine donor at least. Frankly, I have no idea what is going on here. I've had stars that preform differently in the air, but not burn a color on the ground and spray sparks in the air. Was there an appreciable amount of slag on the ground after the star burned by any chance?
flying fish Posted August 31, 2007 Author Posted August 31, 2007 There was little to no slag with the original formula (70/15/15), but with my randomly chosen 60/20/20 ratio there was a good chunk of slag that touched down.
DeAdFX Posted August 31, 2007 Posted August 31, 2007 Try using a mixture of methyl ethyl ketone and acetone when using your nitrocellulose binder. The MEK will allow for a slightly sturdier star at the cost of dry time. Try lowering the copper content a tiny bit. When I was trying to directly subsitute(1:1) hexamine for ascorbic acid in my blue formulas I noticed the color and blue rate just sucked horribly. Perhaps 5-10% copper content might be better suitable? It sounds rather low but if going one way (more copper) doesn't work perhaps going the other way might help... My ascorbic acid blue formula is this. Perhaps this might work with lactose as the two fuels might act more similar.... 65% NH4ClO430% Ascorbic acid5% copper (II) oxide
flying fish Posted August 31, 2007 Author Posted August 31, 2007 Thanks! I usually use NC laquer for initial tests since it dries so fast, but you are right, the stars are not very sturdy. I am now going to try binding them with red gum and "S-L-X denatured alcohol" which is a methanol/ethanol mixture. I'll also try lowering the copper content - I hadn't thought about that before! One other question that I had... any tricks for mixing copper powder into the formula? It doesn't seem to want to mix uniformly. Probably due to the density and particle size (skylighter advertizes it as 60 mesh). I don't know if this will be a problem or not...
pudidotdk Posted August 31, 2007 Posted August 31, 2007 On passfire there is a formula for a blue lance: Ammonium Perchlorate 70 Shellac 10 Copper(II) Sulfate 10 Wood Meal 10 I'll try leaving the wood meal out to make it burn faster and see if it makes a good star.Have anyone else tried NH4ClO4 + CuSO4 comps?
qwezxc12 Posted August 31, 2007 Posted August 31, 2007 Is the copper particle size too big? I've never personally made Cu metal stars, but I've not heard of 60 mesh being used. Of the two accounts I read, one was very fine 200-300 mesh metal from eBay, the other was home-made from Copper Sulfate solution and Zinc, with the Copper metal dropping out as an extremely fine precipitate.
Mumbles Posted August 31, 2007 Posted August 31, 2007 I've used it before in stars, the 60 mesh material, and it has worked just fine. Burn rate was a touch slow, but thats it. I've never heard of anyone being able to get a good color out of copper sulfate. Be sure to use the anhydrous product, otherwise the burn rate will be agonizing. To mix it, I've always just screened it together a few times. When mixing it up to cut, the comp gets solid enough to hold everything in place anyway. If you were going to roll it, it may be a bit more difficult though.
qwezxc12 Posted August 31, 2007 Posted August 31, 2007 Mumbles, I wasn't advocating the use of Copper Sulfate as a coloring agent, but trying to refer to the method of making fine copper powder using a single replacement reaction of Copper Sulfate solution and metallic Zinc, yielding Zinc Sulfate in solution and copper as a precipitate.
Mumbles Posted August 31, 2007 Posted August 31, 2007 I was talking about the post right before yours by pudidotdk, which utilizes the sulfate as a coloring agent.
flying fish Posted September 1, 2007 Author Posted September 1, 2007 You guys are either going to laugh or get pissed at me since this puzzle is definetly not what it seemed (scooby doo style)...I knew there was a reason why I posted this in the newbie forum. I was testing some lampblack willow stars and I saw a similar looking "blue star" accompany my willow star. The fuse! I guess the blue stars probably didn't even light, which means my next step will be looking into primes for it (KLO4 primes, of course). Gosh I feel like an idiot for this one
tentacles Posted September 1, 2007 Posted September 1, 2007 Here's a *very* hot prime from Gene over on Passfire - it's KNO3 based so not appropriate over A perc. "Gene's fence-post prime"65 KNO315 Charcoal (12 balsa, 3 skylighter or something slower - perhaps pine)10 Sulfur5 Silicon powder, 325 mesh5 Diatomaceous earth, pool filter grade (makes the prime VERY fluffy with lots of surface ''points'') Bind with 4% gum arabic solution (or any other binder, really) You should mill the 65/15/10 mix and then add the silicon and DE. Alternatively, you could try KP as a prime, and add some silicon and DE. Most AP blues ignite reasonably well and KP burns quite hot. Just as a side note, I personally have had poor success with veline's prime. Potassium Perchlorate 70 Charcoal Airfloat 18 Sulfur 12 Dextrin 5 The neat thing about silicon is that when it burns, it turns into molten glass (SiO2) rather than atomizing. How hard are you breaking the stars, and with what? That can make a difference too.
flying fish Posted September 1, 2007 Author Posted September 1, 2007 Thanks! I'm not using them in shells yet, the ones I tested that didn't light were from a star gun. Just lifting them with a little Goex FFG. They take a good second to light with a MAPP gas torch, so perhaps I should be looking into more ignightable stars as well as primes.
FrankRizzo Posted September 1, 2007 Posted September 1, 2007 You're absolutely right. If the primed stars take more than a fraction of a second to ignite from a MAPP fueled torch, you will have difficulty using them in shells. If the hot silicon prime that tentacles posted doesn't ignite them readily, you'll need to step-prime. Also, don't try to re-prime leftover stars from a batch with ignition problems. In my experience, unless you can remove the old prime (a *huge* waste of time), you'll just be wasting the chemicals you use for the new priming layer. Instead, use them in mines, fountains, or comets.
tentacles Posted September 1, 2007 Posted September 1, 2007 Hehe, or to light a campfire, like some of the stars I've made.
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