flying fish Posted September 4, 2007 Posted September 4, 2007 This is something that has literally been driving me crazy... I had a shell that failed... I'm now pretty sure the prime for the time fuse was either damp, or it flaked off during lifting. I was testing some AP stars and and using a nitrate burst. I've never had a shell fail before, and I wanted to test the stars without having to make a batch of KP.... So this is a double slap in the face...a failed shell that I put off an ungodly amount of homework to complete, along with a possibly unsafe dud sitting out there in the field (a field which could catch fire, mind you). I would appreciate any information of the specifics of this incompatibility that everyone says to avoid; I need to go back to college tomorrow, but I also don't want to be responsible for a forest fire!!! I also don't want someone else (my dad) looking for the dud if there is a chance of it blowing up while they are handling it.
Mumbles Posted September 4, 2007 Posted September 4, 2007 If it's been more than 6 hours you should be safe as far as duds going off and such. If there was a hangfire or anything, it should have happened by now. If not, you should be fairly safe assuming no one hits it with a lawnmower or something. Exactly what kind of nitrate burst did you use. I think normally someone would have just said BP. Are you using flash or something to burst the shell? The nitrate/AP incompatibility is better in your case. It causes misfires and pretty much inertness, not explosions.
flying fish Posted September 4, 2007 Author Posted September 4, 2007 Thank you! By nitrate I did mean blackpowder - I would normally just say blackpowder but I was getting more to the point of the incompatible chemicals. I've heard over and over than you can't mix nitrates with ammonium perchlorate, but never heard any explaination. This is quite a relief, I will still try to find the shell, but my primary concern was the possibility of a fire being started by a spontaneiously combusting shell.
tentacles Posted September 4, 2007 Posted September 4, 2007 The incompatibility is a reaction where your potassium and ammonium switch the nitrate and perchlorate. You end up with ammonium nitrate, and potassium perchlorate. I wouldn't see a problem with your stars as long as the two materials aren't wet/damp and in contact. Any problem would end up in a misfire.
psyco_1322 Posted September 16, 2007 Posted September 16, 2007 Launch another shell in the day time but make it a dud and see where it falls, if the mortar was straight up, and flat them it more than likey isnt to far from where it was shot. So what happens if I prime my ap stars with bp?
frogy Posted September 16, 2007 Posted September 16, 2007 When Ammonium Perchlorate and Potassium Nitrate are in contact (even if in separate compositions) they can react with each other... They perform a double replacement...NH4ClO4 + KNO3 = NH4NO3 + KClO4 AP+KNO3 = AN+KClO4 Most likely the stars will not work and the prime will ignite oddly... KClO4+C+S does burn... but if may be more of a KP type thing than a prime... Your star composition will not ignite unless there is some type of star that uses AN for an oxidizer
Mumbles Posted September 16, 2007 Posted September 16, 2007 The main problem comes when the AN starts absorbing water. It makes the stars slushy and wet and are difficult to ignite, and will burn poorly. If you prime your stars with BP, chances are they wont be working. There is a way around it though. How I do it is to put on a layer of hot prime(veline super prime) bound with alcohol or water or whatever you feel like. The key to the next part is to make sure the prime dries first. It won't work unless the previous layer of prime is dry. The super prime needs it's own prime to light actually, for this I normally use green meal. You may see a problem here, but there is a solution. I apply the green meal layer with NC lacquer. This seals the BP from the AP star, but doesn't really affect the ignition. One can also apply the other prime layer with NC first, and then apply the green meal right over it with more NC without having to worry about the prime underneath drying,
flying fish Posted September 16, 2007 Author Posted September 16, 2007 That was very informative Mumbles. I think I might give that a try myself... Just thought I'd post to say: I found the shell the day after I posted this topic. Well, actually my dad found it! It did drift quite a ways (about 150 feet), but it was such a lightwieght, and overlifted shell that I'm not surprized. I overlifted it because I wasn't sure how long the stars were going to burn for. Another thing, I found the reason why the shell failed: The time fuse lit just fine, but the fuse appeared to be accidentally crimped at the end, so the sparks shot down out of the shell rather than up into the shell!
swervedriver Posted May 23, 2010 Posted May 23, 2010 Damn, this is why writing down notes are a good idea. I thought I used NC to bind the hot prime on these ammonium perchlorate blue stars a while back, but it appears I fudged and used water. Then I rolled Chrys 8 over them using water. After "drying" I lit one on the ground and a puddle of saturated ammonium nitrate literally squirted out the side of the star. damn, it wasn't to big of a batch but it still sucks. Click on the pic to see whatI mean-
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