Ubehage Posted March 30, 2016 Share Posted March 30, 2016 I have been doing a few tests and experiments with slow flash, in order to determine sensitivity and effevtiveness. I made the usual 50:20:30 composition, and used these types of Al:Flakes ("bright"), Atomized, German Dark and Blue. For all the types, I have successfully ignited the composition by friction between 2 pieces of wood.I have also tested friction between 2 pieces of Aluminum, and only the "bright" Al ignited in these tests.I did all tests 3 times, and none of them ignited every time. In my experience, Blue Al seems to be the most stable to use, also in slow flash.Atomized and Dark Al is workable with the nessesary respect."Bright" Al is definitely the most sensitive, and also makes a mess because it's so easily airborn. Now for the burning of compositions:"Bright" Al burns the fastest. Still 'slow', but comparable to normal flash. And it also ignites very easy with just a spark. Atomized and Dark Al doesn't ignite as well. Normal blackmatch hasn't worked for me - I make one coated with "Bright" Al for hotter sparks.It also burns considerable slower than the "bright" composition.But it makes thrice the boom The Blue Al behaves as the Dark, although it will ignite with a bunch of blackmatch. Link to comment Share on other sites More sharing options...
lloyd Posted March 30, 2016 Share Posted March 30, 2016 (edited) Hmmm... I don't understand why dark aluminum in flash would be hard to ignite. A single 'two strand' black match igniter is all I've ever needed, and I must say (modestly, really), I have _never_ had a load fail to ignite and explode as desired. This, in many decades of making salute inserts. (since the 1960s). LLoyd Edited March 30, 2016 by lloyd Link to comment Share on other sites More sharing options...
FlaMtnBkr Posted March 31, 2016 Share Posted March 31, 2016 Do you know the particle size of the bright and atomized aluminum? Those are some fairly strange results, at least based on my experiences with similar types of aluminum. But I don't really use slow flash and my experiences are with common perchlorate based flash. I wonder how much the sulfur contributes to the sensitivity? My tests with standard 70/30 flash and dark aluminum seem to be considerably less sensitive and perc is usually considered a more sensitive oxidizer that gives up it's oxygen more readily than KNO3. All other aluminum was less sensitive than the German dark and the atomized (both -325 and 400 mesh) I've never gotten to ignite in flash. I would be curious to see how they compare with the addition of sulfur to 70/30 or by removing it from the slow flash. The fact that you got some type of ignition with the blue aluminum is strange and further strengthens my feeling that the sulfur is adding much of the sensitivity and making it more dangerous. It's been quite a few years since I've done a lot of testing of different flash mixes and I used a ball peen hammer on a steel block to really smack the flash and to rub back and forth to produce a lot of friction. And I got very few signs of ignition with perchlorate based flash. I wouldn't call it safe but I was definitely surprised it seemed so insensitive. So I would be curious to see what your results are with perc based. If sulfur is what makes slow flash more sensitive I think I would avoid it. Either use a perc based flash and use less of it or use a coarser aluminum so it's not as powerful. Or use a nitrate flash without the sulfur. It may not be easy to light on it's own, but when it's covering stars and BP grains it will have no problem igniting. I think many people use slow flash because they feel it is safer than 70/30, which doesn't sound like the case with the addition of sulfur. Anyways, interesting results. Link to comment Share on other sites More sharing options...
braddsn Posted March 31, 2016 Share Posted March 31, 2016 The part where atomized and dark AL flash doesn't ignite with BM, confuses me. I have never had an ignition failure with BM, or any kind of fuse for that matter. Make sure you are mixing everything carefully and properly, screening your perc (I like a 60 mesh screen) and your oxidizers/metals are coming from a reputable source. I got a bad batch of dark AL once, and it caused me a lot of headache. Took me forever to figure out what the problem was. Link to comment Share on other sites More sharing options...
FlaMtnBkr Posted March 31, 2016 Share Posted March 31, 2016 The particle size is going to make a big difference so unless we are comparing the same material, like Eckert 5413H German Black, we will likely all have different experiences. It also depends on how much you are trying to light and if you're lighting a test pile in the open or a finished shell, in my experience. Trying to light 4g in a tube seems to be harder to light than 25g in a ball shell. I haven't got straight atomized aluminum flash to ever light, but it sounds like Brad has. I have a mix where part of the expensive dark aluminum is replaced with atomized for larger salutes that is probably pretty similar to what is now called blue aluminum, but it's not the same thing. The results to seem strange since he had problem lighting some with fuse yet got an ignition with friction. I would be curious what the signs of ignition were like? Was it a pop? Or a little smoke, or just a burnt match smell like I got? Link to comment Share on other sites More sharing options...
Mumbles Posted April 3, 2016 Share Posted April 3, 2016 How reliable is your source for german dark Al? I only ask because the information provided is kind of at odds with what I know and have experienced. I know you're from the EU, but there seems to be some fake or mislabeled german dark Al available in the US. I'm not sure if the same may be true for you as well. Also, how are you mixing these mixture? I'm not sure if different grades would be mixed to different degrees if not screening. Just brainstorming. Link to comment Share on other sites More sharing options...
Ubehage Posted April 7, 2016 Author Share Posted April 7, 2016 Mumbles, I'm actually not sure how reliable my source is.. I always considered them to be professional and reliable, but I don't have any to compare with.I bought the Aluminum about 18 months ago, from PyroGarage, Link to comment Share on other sites More sharing options...
asdercks Posted April 7, 2016 Share Posted April 7, 2016 I really find it hard to believe that flash using dark aluminum won't ignite using black match,are you sure you did not mixe up your aluminum or samples, in my experience flash made with dark aluminum burns faster than flash made with bright Al, but as others have said I guess particle size and quality of chems play a roll in performance, just my two cents Link to comment Share on other sites More sharing options...
Sparx88 Posted April 8, 2016 Share Posted April 8, 2016 I have never used bright, atomized or blue for flash comps. Reason why, I tried bright and atomized/spherical like alcoa for flash and they did not do anything at all resembling what 5413 does. Shit lights with an incense stick, more so if sulfur is added. But thats how my BP and a lot of star comps light is by incense so I'm not to terrbly bothered by it. Caution is your friend. I treat all of it like it could be my last you know I do however add a small bit of the others for a longer flash or for sparks like a ti salute. 5413 for me is the top shelf, used for standard flash, slow flash, star comps...if it is'nt a glitter, it 5413. Link to comment Share on other sites More sharing options...
Recommended Posts