Pirotecnia Posted May 27, 2012 Posted May 27, 2012 Hi, I've make the Chrys 8 composition, and now i want to make some rolled stars.I want to know if it need a BP prime or not, thanks!
dangerousamateur Posted May 27, 2012 Posted May 27, 2012 No, it doesn't. But a thin final layer of BP sure would help to engulf them more uniformly.
burningRNX Posted May 27, 2012 Posted May 27, 2012 Be sure that you don't roll them too smooth at the end.The must be somewhat like sandpaper with a lot of surface area.If you do so I don't think its nessesary to roll a final BP layer, but hey, why not?I always do.
Seymour Posted May 27, 2012 Posted May 27, 2012 Depending on how you treat them, they may light without prime, but I do not suggest it... often some stars will only light from one side so you get irregular burn times and strange star trajectories. In hard broken shells this will be more severe, and they may blow blind. As said, a quick meal prime will mean reliability. It's best to always prime glitters and charcoal streamers with black powder, even though you can often get away to some extent with skipping the step. BurningRNX, while I fully understand the logic behind a rough surface for higher surface are (for which reason some pyros go so far as to add wood meal to the prime to get texture), I do not think it is significant. If your stars need twice the surface area, you have a problem. A rough surface is no substitute for good priming, and a rough surface is most definitely not a 'must'. Manufacturing stars comprises of a significant part of my job, and I make sure that at the end they're all very smooth and hard on the final outer surface. While it's rarely going to matter at all, I definitely value the extra strength of the consolidated prime when smashing them with really hard bursts. Rough primed stars don't have this compaction on the final layer, and you can tell this because you can scratch them.
fredhappy Posted May 27, 2012 Posted May 27, 2012 (edited) pirotecnia: I'd advice to make it a habit to prime everything, charcoal streamers included, 1 mm will do nicely. seymour: That is an interesting point you bring up. My stars are very smooth when I finish with applying the prime with the toro method. When I would dry these smoothly primed stars and shoot them , some still would be blown blind, despite the correct thickness of the prime layer. I have experienced that when I simply dust these smooth wet stars with fast meal this problem does not occur anymore. I also do attest to the need for very well integrated and consolidated prime layers, but the final dusting does make a difference for me. I like breaking hard with 7/1 KP on hulls. Edited May 27, 2012 by fredhappy
burningRNX Posted May 27, 2012 Posted May 27, 2012 Ok, well right, just everywhere i read they just prime everything with corning dust , wood meal and so on to get surface area, so I assumed it was key part in failure of priming.Maybey it's just a way of them to get it right without rocket science priming.1 mm is a lot of room, so what do you guys suggest? could it be less?
dagabu Posted May 28, 2012 Posted May 28, 2012 I prime all my stars with corning dust or 7FA or Meal-D, whatever I have around on the outer layer, they light at the same time, burn out at the same time and will take a heavy break or a lite break. I never know what I will be using the stars in so I make sure they will light no matter what I do with them. -dag
Seymour Posted May 28, 2012 Posted May 28, 2012 1 mm is a lot of room, so what do you guys suggest? could it be less? With C8 I think so. Charcoal streamers are practically impossible to blow out due to high speed. You only need a thin layer that will be largely consumed with (and contribute towards) the burst, but Ok, well right, just everywhere i read they just prime everything with corning dust , wood meal and so on to get surface area, so I assumed it was key part in failure of priming. I'm sorry, I feel I came across as a bit dismissive. There is no doubt that increasing surface area helps with ignition, but this is still combined with the use of fairly good quality black powder, like cross matching spollettes and using corning dust or grain on stars and fuses. While both are important, I think the ignitability of good quality BP is more important. There's nothing fancy in this, just black powder. All the 'rocket science' priming is people avoiding step priming, or just people enjoying fancy chemicals for the novelty or feelings or being elite. Even then it's rare for there not to be a final coating of good old BP. Fredhappy, Did you also use good meal for the final toro wet layer? If not I'd guess it's the meal, but otherwise I'm happy to concede that you are right. I've noticed that some Japanese stars I've seen from opened shells are like this, but I just thought that it was due to decay during their age and neglect. I can assure you all that mould grows on BP grain alone, or should it be "GP" for 'green powder'. Dagabu, is 7F real, or are you just jokingly saying 'the fine fine stuff'? I graded out some really nice, if nearly useless fine grains from corning dust and was told I'd just split 4f in to various fractions.
Mumbles Posted May 28, 2012 Posted May 28, 2012 7FA is a real powder. It's -40+100. It's pretty much interchangable with Meal D. As best as I can tell, it's basically meal D with the really fine powder removed. I've never actually dealt with it personally, but I've seen cases of it.
dagabu Posted May 28, 2012 Posted May 28, 2012 Dagabu, is 7F real, or are you just jokingly saying 'the fine fine stuff'? I graded out some really nice, if nearly useless fine grains from corning dust and was told I'd just split 4f in to various fractions. Indeed it is and it's available here for $5.00 a pound. Mumbles is correct, it is meal-d with the fines removed and is the same mesh size as 116 Fuse powder. http://www.addictedtoblackpowder.com/2.html -dag
fredhappy Posted May 28, 2012 Posted May 28, 2012 (edited) seymour : No , previously I did not finish with a last layer of meal. Since fencepost is being touted as a "light all solution" I thought it was not necessary to apply that last meal layer. I was wrong, and since I apply that last layer my stars ignite much better then with fencepost alone. So please keep in mind that even with fencepost, which I do think is a very good prime, a final dusting with quality fast meal made with softwood charcoal (willow , balsa etc) is needed to ensure proper ignition. mumbles/dagabu: please keep in mind that in other countries it is not possible to buy meal and gunpowder so easily as it is in the U.S.A. I do not think pirotecnia is from America, so I think he has to learn somehow how to make it himself. Give a man a fish and he eats for a day, teach him how to fish... ( I don't mean this in a negative way). dagabu: do you happen to have some pictures/clips of your stars igniting with the hard breaks you describe , or perhaps some pictures of primed stars cut in halve ? Edited May 28, 2012 by fredhappy
dagabu Posted May 28, 2012 Posted May 28, 2012 dagabu: do you happen to have some pictures/clips of your stars igniting with the hard breaks you describe , or perhaps some pictures of primed stars cut in halve ? Sorry but my hard broken shells didn't get video'd, I was lighting them. I do have stars to cut but it will be a couple weeks till I get back to the shop. -dag
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