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Monocapa question


braddsn

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I really figured out the drying stuff when I first started, this is not the problem. They are uncrushable, my way to test is throw it as hard as i can to the concrete, and it doesnt crack. Dextrin keeps amazing me.

 

I think dag scored on this one, my biggest problem is the candycoating, perhaps combined with too little prime.

 

Im currently getting into pumping, but will roll a batch for test asap. Thanks guys, appreciate everyone's reply!

 

Thanks En, keep in mind that it is important to weigh your comp before rolling and again after (everything on the same scale) to determine how "dry" the stars are. I made a batch of crossettes and weighed them several times, I was amazed that they held a full 4% moisture for a month then one day, they were at their base weight (retained about 1.5% moisture).

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I was having difficulty with a batch of pyro science blues ignighting when testing in a star gun. Switched to Monocapa as the prime and problem solved. Brad if you get a chance and have the chems to make Jopetes color stars they will not disappoint. Very deep saturation and the brilliant whites are indeed brilliant.
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db5086, beware that the pyro science blue burns reeealllllyyyyyyy slow.. lol. I found out the hard way.. hehe. Every formula that I have mixed from Jopetes so far has been excellent! The yellow is truly a lemon yellow! I was impressed. And the stars that I have primed so far with monocapa light every time. I am now a monocapa user for life! :)

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Perchlorate blues are notorious for being rather hard to keep lit. Besides just having a prime capable of lighting them, you need to make sure they've slowed down enough to stay lit. For whatever reason, they are much more prone to being blown out at high speeds than other compositions. Perhaps it's just an organic vs. metallic thing since most other colors are most popularly made with metals currently.

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Funny that Mums just mentioned this, because tonight I fired some blues from my stargun, and noticed something interesting and just logged on here to post about it. I fired the star gun 3 times, 4 stars in each shot. The stars are primed with monocapa, then a final layer of bp+mgal and small granules of bp. The first shot: it appeared that the stars blew blind. I was stumped, because monocapa has been lighting everything so consistently. Reloaded gun. 2nd shot: I watched closer.. and saw that the prime lit. Well, I knew that if the monocapa lit, it HAD to light the blue.. so I fired a 3rd time with bigger stars (same batch) and watched again. Low and behold, prime lit, then the blue... then it blew out quickly. I know I am just repeating what Mumbles just posted, but I watched it with my own eyes and in close proximity. They blew out, whereas all of my other stars stay lit with no problems. So the only solution to this problem is to prime thicker to give the stars a chance to slow a bit before the blue comp lights. Or, I guess a chlorate star would work :(

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Braddsn you can also try to add some al (2-5%, best flash grade atomized or -325 flake) to your stars. This will raise the temperature but keep them burning much better. The big downside is off course that some blues can't handle the raised temperature.
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I have actually not had this problem - yet.

Could meshsizes be relevant? Im thinking, the finer the copper oxide the easier it burns. Also, my perchlorate is ALLWAYS ground to a fine powder in a nice coffegrinder.

Mixing well goes without saying. A whisk really makes the mixing process alot quicker IMO.

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Schroedinger..I may just experiment with that if thicker prime doesnt work. Enanthate I believe that chems being the right consistency and mixed through a proper mesh screen makes all the difference. My Kclo4 and copper oxide for example are fine powder like talc. And when I get chems that are clumpy or granulated, i ball mill them. My strontium and barium nitrates are usually not fine powder so i ball mill them. The process of cleaning the mill jar and media is a pain, but its why i have a ball mill :) Edited by braddsn
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Funny that Mums just mentioned this, because tonight I fired some blues from my stargun, and noticed something interesting and just logged on here to post about it. I fired the star gun 3 times, 4 stars in each shot. The stars are primed with monocapa, then a final layer of bp+mgal and small granules of bp. The first shot: it appeared that the stars blew blind. I was stumped, because monocapa has been lighting everything so consistently. Reloaded gun. 2nd shot: I watched closer.. and saw that the prime lit. Well, I knew that if the monocapa lit, it HAD to light the blue.. so I fired a 3rd time with bigger stars (same batch) and watched again. Low and behold, prime lit, then the blue... then it blew out quickly. I know I am just repeating what Mumbles just posted, but I watched it with my own eyes and in close proximity. They blew out, whereas all of my other stars stay lit with no problems. So the only solution to this problem is to prime thicker to give the stars a chance to slow a bit before the blue comp lights. Or, I guess a chlorate star would work :(

 

Brad,

 

I had the same problem with some perc/parlon (dex binder) blues that I was pushing hard out of the star gun. I found that increasing the layer thickness of the monocapa under the BP outer prime cured the problem. Of course, it could also have been the star slowed enough once the monocapa burned off to remain lit. In my case, I'm leaning towards the slowdown of the star because the 'capa was igniting and burning fine without a BP prime when fired hard from a star gun. Parlon may also be the culprit here but haven't tried any subs for it yet.

 

Got the winter doldrums here and haven't done much pyro lately.

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Bobosan, I firmly believe it's a matter of getting the stars slowed down enough before the blue comp lights. I watched as the blue color fired up and promptly burned out. These were 10mm stars.. they should have burned all the way to the ground. The blue lit, and was out in 1/2 second. I am wondering if a blue comp with metal might be better. Either way, tonight I am headed up to do some more testing. :)

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