stix Posted February 21, 2015 Posted February 21, 2015 I've got some 17mm (approx. 5/8th") pumped comets (spider composition). I'll be testing these in a star gun and after doing a fair bit of reading I'm still not sure. I can understand the point of wrapping in a couple of layers of kraft for rising comets on shells, but what about shooting from a mortar or star gun? I'm guessing it depends how fast I want them to burn - ie. faster with no wrap - slower when wrapped, with better tail effect. What do you guys do? Cheers.
pyrojig Posted February 21, 2015 Posted February 21, 2015 Ive always wrapped them for longer burn-times. Unless I was after a larger flame and using a slower comp like TT, then no wrapping .
stix Posted February 21, 2015 Author Posted February 21, 2015 Thanks pyrojig. The spider comp seems to burn pretty fast. I have 3 comets roughly the same length. So I reckon I may as well do three tests. 1. Static burn test on the ground as a comparison to this test: http://www.amateurpyro.com/forums/topic/10547-spider-stars-burning-too-quick/?do=findComment&comment=140381- post #10 from nater. 2. Comet without outer wrap. 3. Comet wrapped in 2 layers of kraft paper. Just a couple of other questions: What about the top - should it be inhibited as well? Also, I have the option of using kraft, gummed tape or aluminium tape - do you wet the first layer wrap if using paper or the first layer is dry? Cheers.
nater Posted February 21, 2015 Posted February 21, 2015 You can wrap the sides only, or paste in one edge too. Pasting one edge will force the comet to burn from one end to the other like a candle, pasting the sides only allow the comet to burn from both ends and not pasting the comets at all allows them to burn from the outside in. Some people brush the sides of the comet which will be pasted with nitrocellulose lacquer before pasting to make the process a little neater. I use pasted Kraft strips on my calendar city comets, no dry wraps. Whatever edges are exposed, get primed with a NC and BP slurry then dipped in fine grained BP.
stix Posted February 21, 2015 Author Posted February 21, 2015 (edited) Ok, Thanks nater. I don't think I will need to prime the spider comp, so I'll wrap the cylinder and also inhibit the non fire end on one test. The other two tests will be done as suggested before. Cheers. Edited February 21, 2015 by stix
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