Wiley Posted March 4, 2015 Posted March 4, 2015 So I made some brocade stars, basically Ned Gorski's Tiger willow formulation with 10% ferro-Ti added. They appear fully dry, but when I fire them out of a star gun, they perform normally except that a bunch of smoldering "hail" comes raining back down and splats all over the ground. Could this be because I did not dissolve my nitrate in enough water and therefore didn't get the oxidizer well incorporated, or is it something else? I'm using the boiling water technique to make cut stars that I posted earlier.
Andres1511 Posted March 4, 2015 Posted March 4, 2015 Your charcoal is probably to course, so the particles still burn/glow when they fall on the ground.
Wiley Posted March 7, 2015 Author Posted March 7, 2015 I made a batch of stars recently that was basically tiger tail with 10% added metal (coarse and fine FerroTi), and the stars have the opposite problem as the last batch. When lit, they actually take flight and appear to burn very cleanly (almost no sparks). A 1/4" star burns in under a second. I used a homemade cedar/fir charcoal (-20 mesh down to airfloat) that could be the culprit.
psyco_1322 Posted March 7, 2015 Posted March 7, 2015 You might have just mixed the first batch wrong, it happens sometimes. You really don't need to dissolve the nitrate in the water. Just mixing the comp well and wetting with enough water to cut will be fine.
Wiley Posted March 8, 2015 Author Posted March 8, 2015 I used granular nitrate on the first batch, so I figured it needed dissolving. Any ideas on what might have gone wrong with this second batch (just metalized TT)?
psyco_1322 Posted March 8, 2015 Posted March 8, 2015 The particle size of charcoal will really effect how things burn. Anything larger than airfloat tends to have a hard time actually burning up. For instance, screened bp that's made with say 80mesh charcoal will burn like crap, and have lots of slag from the extra oxidizer that isn't being used. So since you are lacking the full amount of airfloat, it's not surprising that they burn a tad faster than normal. Coffee grinders do wonders for powdering your nitrate.
Wiley Posted March 8, 2015 Author Posted March 8, 2015 So coarser does not necessarily equal a slower burn with charcoal? If that's the case, I'll try again with commercial airfloat.
Wiley Posted March 9, 2015 Author Posted March 9, 2015 This second batch of stars has the same issue as the first; they burn vigorously, but leave behind a glowing chunk of what appears to be unreacted charcoal about the same size and shape as the original star. In the air, they do the same thing, and those glowing embers come streaming back in and splatter all over the place. I've cut a few open, and though the prime layer is hard and crusty, the innards are still soft and appear to be completely dry. Not soft as in squishy, but soft like a stick of pine charcoal straight after being cooked in a retort (easy to scratch). They burn almost as though they were just lumps of charcoal. What could possibly be going wrong?
Mumbles Posted March 9, 2015 Posted March 9, 2015 The burning behavior on the ground is pretty normal. Many formulas designed to leave long-lasting tails tend to rely on atmospheric oxygen to complete combustion. On the ground they'll actually burn fairly quick, leaving a glowing ash or cinder behind. In the air, this layer is blown off as the star flies through the air which gives rise to the desired long tail. Excessive fallout as you've described normally comes about from some sort of coarse ingredient in your star. It could be nitrate since you're dissolving it all in water first. Dissolving it in water might work for polverone, but not here. Since airfloat is giving you the same results, this is actually what I'd suspect. You might want to try a batch with a powdered sample and see if that makes a difference. If you have a ballmill available, milling the composition for a short while sans FeTi might also be an option. 2
psyco_1322 Posted March 9, 2015 Posted March 9, 2015 Yes, coarse charcoal is not as oxygen demanding as fine airfloat. That really sounds like your stars may not be dry. There is a state of little moisture where they are soft and easily scratched. With charcoal stars, you don't want to add any prime layer before they are completely dry. The prime layer drys much faster and will seal in moisture, guaranteed way to get driven in stars. Try 100% airfloat, and make sure they are good and dry. They should have white lines when scratched, and it shouldn't crumble apart. Get some video if you can also. 1
Wiley Posted March 9, 2015 Author Posted March 9, 2015 Ok, I made a small batch of brocade, cut into 1/4ish inch cubes. I let them sit for a few minutes after cutting, and they became durable enough that I could scrape them up with a putty knife and transfer them to a drying screen. They had also lost most of their shininess and were no longer sticking to each other. They are currently sitting in a remote HF food dehydrator. We'll see how they turn out. Also, that batch of D1 I made dried properly, so I have those to compare this batch of brocade to as far as hardness goes. Thanks for all the tips!
stix Posted March 9, 2015 Posted March 9, 2015 . . . You might want to try a batch with a powdered sample and see if that makes a difference. If you have a ballmill available, milling the composition for a short while sans FeTi might also be an option. I'm certainly no expert, but what mumbles has mentioned is absolutely good advice. I think you have become confused with - "Ned's Nitrated Baggie Method for Charcoal Stars" and forgot about some basic methods. Neds' Baggie method seems really easy and a shortcut, but in my view, it's a method that is only suitable for levels of expansion of a knowledge base that's already there! An analogy: TT, (tiger tail) is the pyrotechnics version of "Hotel California" for would be guitarists. Cheers.
Wiley Posted March 10, 2015 Author Posted March 10, 2015 So after one day in the drying box, the stars are hard on the surface. Cut them open and they are soft in the middle. Is this normal at this point, because it seems to me that moisture is going to have trouble escaping. I'll see if they are getting any drier tomorrow .
Xtreme Pyro Posted March 10, 2015 Posted March 10, 2015 So after one day in the drying box, the stars are hard on the surface. Cut them open and they are soft in the middle. Is this normal at this point, because it seems to me that moisture is going to have trouble escaping. I'll see if they are getting any drier tomorrow . Normal, give them a few days and they'll eventually dry up.
Wiley Posted March 10, 2015 Author Posted March 10, 2015 Cool, I was just afraid that putting them straight in the drying box would drive them in, but it still gets below freezing at night so I had nowhere else to put them. Some of them also exhibit little "veins" of recrystallized KNO3 on the surface; is that to be expected?
psyco_1322 Posted March 10, 2015 Posted March 10, 2015 What you are experiencing is essentially driven in stars. I'm surprised it happens with them that small actually. I suppose it should have been noted that heavy charcoal and glitter stars should get a good day of drying in front of a fan before force drying. Colored stars pretty much never get driven in, you can pop them right into your drying box. 1
Wiley Posted March 10, 2015 Author Posted March 10, 2015 Well, I'll see what they look like at the end of today. Where do you suggest I put them with the fan blowing on them?
Maserface Posted March 10, 2015 Posted March 10, 2015 It could be that they are driven in, another possibility is that the warmth caused the nitrate to 'move' to the surface of the stars, leaving a fuel rich center, ive heard of this happening more-so with directly drying in the sun, but its a possibility.
Wiley Posted March 10, 2015 Author Posted March 10, 2015 Hmm, I may have to try another batch with the fan technique.
stix Posted March 11, 2015 Posted March 11, 2015 Hi Wiley, What psyco said about being driven in could be the case. It could also be they are not dry enough yet, how long are you drying them for? I had a look at your recent posted shells video and can see you are at a more advanced level that I am. I especially liked the salutes . Have you always being doing the "boiling water, baggie method" or is this the first time you have tried it? I would imagine that as the mixture cools down there is a point that if you keep kneading into dough, and as the KNO3 recrystallizes, it would then make the mix less incorporated, which may explain: "Some of them also exhibit little "veins" of recrystallized KNO3 on the surface". Anyway, for what it's worth, I've had a very similar outcome recently regarding the "smoldering hail" albeit on a smaller scale. I made my first small batch (50grams) of TT about 2 weeks back. I split the comp in half and ballmilled 1 lot (1hr), and the other I just screened. I cut 1/4" stars and let them dry out for about 10 days, the first 2 days I had a fan blowing over them. They are rock hard. I cracked one open with a sharp knife and scraped the inside to be sure - a thin white line and not soft at all. So I did a small test the other night in a 1/2" star gun. The ballmilled stars burnt well leaving a beautiful tail, the screened version burned ok but most ended up on the ground as a smouldering red hot lumps of coal. The reason was it was not well incorporated. I won't bother screening TT again. I do like the promise of the "baggy method" so I'll be interested to see your issue solved - not just for yourself, but so as I can learn something too Cheers.
Wiley Posted March 11, 2015 Author Posted March 11, 2015 This is the first time I tried the baggie method. I don't have a ball mill, so screen mixing is what I'm going to use for my comps. I know my D1 stars work ok, so I can continue making those the way I am, but I have chems coming to make colored stars, so we'll just have to see how that goes. I may try again with charcoal stars and a little tip from braddsn about using 75:25 water:alcohol and letting them air dry for at least 24 hours. I have been using straight water up to this point.
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