Bonny Posted February 28, 2008 Posted February 28, 2008 Well now that i've launched severall successful D1 shells i want to move on to a different star comp, so i figured why not try ruby red and emerald green. My only problem is i am only able to get hold of 258 Mesh MgAl, i'm just wondering if this will be suitable for this composition? or if i need to get hold of finer MgAl somehow. Any help would be much apreciated MgAl can be ball milled to a smaller size as it is so brittle and breaks up easily.
nath0r Posted February 28, 2008 Posted February 28, 2008 Thanks for the help, I've just put in an order for some MgAl and a few other chems and i look foward to making some of these beautiful stars.
Zmuro Posted March 14, 2008 Posted March 14, 2008 Can I replace Red Gum in this formulas with some other resin.
qwezxc12 Posted March 14, 2008 Posted March 14, 2008 As it's a fuel, not a binder (and present in such a small percentage) you might be able to sub a synthetic resin in it's place. You might also be able to up the charcoal % in it's place as well. I think you'll have to just make a test batch and see.
Zmuro Posted March 27, 2008 Posted March 27, 2008 How long do i have to ball mill this composition (except magnalium). Is it the same as for C8 and TT?
Mumbles Posted March 27, 2008 Posted March 27, 2008 No ball milling required, just screen together. Really only charcoal comps need to be ball milled. Even glitters normally don't.
Zmuro Posted March 27, 2008 Posted March 27, 2008 So i shouldn't mill strontium nitrate, red gum, charcoal, sulfur, dextrin and parlon together for about 10 min and then screen in magnalium and perchlorate. My strontium nitrate is like fine sand and charcoal isn't airfloat.
oskarchem Posted March 27, 2008 Posted March 27, 2008 Well, mill the charcoal until it is airfloat, and then just screen each chemical seperatly so that there are no lumps, next screen all of the chemicals together.
justanotherpyro Posted March 27, 2008 Posted March 27, 2008 You can always screen everything together and burn a small pile of loose comp to see if it burns well enough. If you still have doubts then press a small star out of the "raw" composition and do a star gun test. If it shoots blind or burns poorly/slowly then you know that you need to ball mill it. It wouldn't be recommended to ball this batch though because it does have the MgAl fuel in it.
Mumbles Posted March 28, 2008 Posted March 28, 2008 Well that was assuming you were starting with appropriately fine chemicals, which you are not. You'll want to individually mill the nitrate and charcoal to airfloat.
Zmuro Posted April 11, 2008 Posted April 11, 2008 I tried to ballmill strontium nitrate and after 3 hours I open the jar and there is just big ball of nitrate and it's rock hard, WTF!
Pretty green flame Posted April 11, 2008 Posted April 11, 2008 I tried to ballmill strontium nitrate and after 3 hours I open the jar and there is just big ball of nitrate and it's rock hard, WTF! Sr(NO3)2 is very hygroscopic so i guees the powder absorbed enough atmospheric moisture to clump together pretty badly. Somehow break it up and salvage what you can.
Mumbles Posted April 11, 2008 Posted April 11, 2008 Actually Sr(NO3)2 isn't very hygroscopic, about as much as KNO3 IIRC. It's a contaminate that makes it such a pain in the ass.
Pretty green flame Posted April 11, 2008 Posted April 11, 2008 Actually Sr(NO3)2 isn't very hygroscopic, about as much as KNO3 IIRC. It's a contaminate that makes it such a pain in the ass. You're right Mumbles, IIRC it's Strontium chloride that's responsible for the hygoscopicity.
FrankRizzo Posted April 11, 2008 Posted April 11, 2008 Strontium chloride is not the most likely suspect. Most SrNO3 is made from calcium nitrate (deliquescent) and a soluble strontium salt.
Zmuro Posted April 12, 2008 Posted April 12, 2008 I made a 100g batch of ruby red: http://shrani.si/f/3G/1i/2If59BYV/ruby-red-test.wmv, does it burns fast and bright enough?
TheSidewinder Posted April 13, 2008 Posted April 13, 2008 Not bad. But I think you need to get your chemicals more finely ground and mixed better. I saw slag flying off, and that shouldn't happen. Screen through a 40 or so mesh, three times, gently "rubbing" the comp through if it clumps up, then mix the result by hand or by tumbling (NOT milling) in a small drum. Most of my problems the first year I made stars, were because I wasn't mixing well enough.
yellowcard Posted April 13, 2008 Posted April 13, 2008 I had a question about the priming of ruby red and emerald green stars. Do you have to roll your prime over the stars directly after you rolled your ruby or emerald stars, or do you have to dry them first for 1-2 days, and then prime them ? Thanks . I make these stars all the time, with 325mesh MgAl, and they're really beautiful .
Zmuro Posted April 15, 2008 Posted April 15, 2008 I have the same question but I have pumped stars, so how can prime them because if I put them in star roller it would crush the edges.
TheSidewinder Posted April 15, 2008 Posted April 15, 2008 Pumped or cut stars should be hand dusted with your prime while they're still damp, turning them several times as you dust them. Rolled stars are the same. You need them to be damp to hold the prime.
qwezxc12 Posted April 15, 2008 Posted April 15, 2008 I dry my pumped stars completely, then prime them in the roller. Misting them with water doesn't work very well, so I use a thin slurry of prime (prime toro, if you will) to get the dry prime to adhere initially and for additional layers. I use a BP/Si mix for prime on all non-AP based stars.
crazyboy25 Posted April 15, 2008 Author Posted April 15, 2008 I roll them then wait 10-15 minutes then roll on the prime making sure to use more then required.
justanotherpyro Posted April 18, 2008 Posted April 18, 2008 When I make a large batch of pumped stars I use a wok to roll them around while spraying. When they are evenly wet then I transfer them to my bowl of BP/Si prime and shake it back and forth a few times.
Mumbles Posted April 18, 2008 Posted April 18, 2008 I mentioned this to someone in a PM. My personal preference is to let the stars dry. The theory is different comp, different shrinkage rates. I don't know if it'd really matter, but I'd rather not take the chance. In any case, you'll want to size them after they are dry and prime the good ones for use in competition shells and such. I make mostly cut stars anyway, and trying to tumble them while wet would result it them being demolished. I use a layer of hot prime (veline style super prime), and a layer of green meal to prime these specific stars.
nath0r Posted April 19, 2008 Posted April 19, 2008 I also let my pumped stars dry completely before i prime them, no real reason for this, it's just how ive always done it. As for these ruby red/emerald green, i use only a coating of BP slurry as prime and it seems to light the stars with no problem, when i was first reading up on these stars i was really expecting them to be a bugger to light. I havent launched any shells with this comp yet but i do have a 4in ruby red shell waiting for me when i return home from holiday. From some ground tests of these stars they will look amazing up in the sky, i couldn't believe how bright they were.
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