BillyBobBodean Posted April 22, 2015 Author Posted April 22, 2015 I don't see that listing. How much is it with shipping? I paid $12 including shipping. There was only 1 left.
nater Posted April 22, 2015 Posted April 22, 2015 FlaMtnBkr - have you tried TPA flash with light confinement such as a flash bag burst, or do you think strong confinement is needed? 1
BillyBobBodean Posted April 25, 2015 Author Posted April 25, 2015 FlaMtnBkr - have you tried TPA flash with light confinement such as a flash bag burst, or do you think strong confinement is needed? Good question I'd like some info on too!
FlaMtnBkr Posted April 25, 2015 Posted April 25, 2015 It works in a flash bag. But that really has good confinement since it's in the middle of a pasted shell. Not sure how much is required for the confinement to be enough. Probably not a ton if it will allow pressure to build even for just a millisecond. Once there is pressure the speed of burn is much faster than most other fuels. A 1/32" tube is plenty. I actually mix in a zip lock bag. If it somehow started burning it would melt and not let the pressure build. It also burns so slow that if it did light unconfined you could get up and walk away as it burns. I imagine there is a mass where it can provide enough containment from it's own weight. But I think that would be more than most hobbyists make at once. Would also depend if it lights at the edge or in the center or bottom of the pile.
Nessalco Posted April 25, 2015 Posted April 25, 2015 The self-containment amount is unknown, but more than 500g. I lit that amount with an ematch dead center of the pile, and it burned nicely - but did not explode. Kevin
OblivionFall Posted April 25, 2015 Posted April 25, 2015 Why use TPA and not just Blue Aluminum powder? Unless of course you're making small salutes.
mikeee Posted April 25, 2015 Posted April 25, 2015 A safer material for bottom shots for cylinder shells. No fun when the bottom shot on a larger cylinder shell goes off from the lift charge.
FlaMtnBkr Posted April 25, 2015 Posted April 25, 2015 Blue aluminum is more expensive unless the price has come down lately. Blue aluminum needs a hot primed fuse. It needs to be at least 10g to fire reliably. I have a bunch of TPA and no blue aluminum. I've been using and pushing the use of TPA for about 6 years now and used to it and like it. If you have blue aluminum and don't mind making it work then either is likely 'safer' than the standard stuff and either is probably good for the hobbyist. Some will probably prefer one over the other. Also, TPA can be used in 'non-toxic' military smoke if you like smoke 'bombs'. 1
OblivionFall Posted April 26, 2015 Posted April 26, 2015 Blue aluminum is more expensive unless the price has come down lately. Blue aluminum needs a hot primed fuse. It needs to be at least 10g to fire reliably. I have a bunch of TPA and no blue aluminum. I've been using and pushing the use of TPA for about 6 years now and used to it and like it. If you have blue aluminum and don't mind making it work then either is likely 'safer' than the standard stuff and either is probably good for the hobbyist. Some will probably prefer one over the other. Also, TPA can be used in 'non-toxic' military smoke if you like smoke 'bombs'.Makes sense. Blue Aluminum is about $14-18 per LB from hobby horse after shipping.
BillyBobBodean Posted May 16, 2015 Author Posted May 16, 2015 Sorry to bug you on this again, but here is what my experimentation has resulted in. Made 10 grams of TPA flash, tested in small 1" plastic ball shells, just caught fire, no boom. Tested in small cap plugs and in small 1/4" tubes, nothing at all. I decided maybe my TPA was bad (I had dried it and milled it in a coffee grinder to pass through 100 mesh). I decided to try 70/30 flash, made a 2 gram batch, filled 3 small cap plugs and inserted time fuse. None of the 3 did anything. After waiting a day I carefully cut open all 3 cap plugs and the time fuse did burn through. Sorry for the long post, my KCLO4 was dry and passed through 100 mesh. In your expert opinions is my Perch not fine enough, or did I get screwed on the Ekart 5413H Aluminum I purchased on ebay?
mikeee Posted May 16, 2015 Posted May 16, 2015 A few of our club members have been using TPA flash for inserts and bottom shots. Most of these used a small style HE detonator cap to set the TPA off. That is what makes the TPA safe, a strong lift charge will not set off. You need a detonator style ignition to set the TPA off.
WonderBoy Posted May 16, 2015 Posted May 16, 2015 Actually mikeee, I think you are confusing TPA with something else. We have not been using caps in our inserts nor bottom shots, just spolettes or timefuse. I believe the problem you are thinking about is a heavily flash broken shell "detonating" the bottom shot, not the lift causing a malfunction. WB
nater Posted May 16, 2015 Posted May 16, 2015 Flash made with blue aluminum needs something to get it going. A good spolette or flash bag helps. I have not picked up my bucket of TPA yet. 10g is a small amount, is it possible the tiny cap plug salutes is not enough confinement? Do you prime or cross match your time fuse? Flash does not always ignite from the flame spit from time fuse alone.
FlaMtnBkr Posted May 16, 2015 Posted May 16, 2015 Get the 70/30 to work first. 2g in a tube or a few wraps of paper and tape should show you why people say to be careful with flash. If it isn't working right something is wrong and you need to figure that out before going after the TPA flash. 1
GMetcalf Posted May 16, 2015 Posted May 16, 2015 Did the flash ignite at all? Or when you cut the tubes open was there still the same grey powder you put in there?
BillyBobBodean Posted May 17, 2015 Author Posted May 17, 2015 Did the flash ignite at all? Or when you cut the tubes open was there still the same grey powder you put in there?Still the same grey powder. I know my perch is good as the stars I have made with it burn just fine. I think I'll make a 1 gram batch and just put a flame to it and see the results. Thanks!
GMetcalf Posted May 17, 2015 Posted May 17, 2015 If you have any Visco fuse you can give it a go at igniting it with that. Even an average 70/30 Flash Powder should take light pretty easily. If it lights with Visco then I can't see why it shouldn't light with Time Fuse.
Ubehage Posted May 17, 2015 Posted May 17, 2015 Flash made with blue aluminum needs something to get it going. A good spolette or flash bag helps.You also need a certain amount of flash, or it will not ignite.I'm not sure about the specific amount, but to my experience I could not get anything below 7 grams to explode. It also helps if you use some fast-burning BP; that will make it possible to use even less BP to get it started.The "blue" Flash needs to get pressurized and ignited at the same time.
BillyBobBodean Posted September 3, 2015 Author Posted September 3, 2015 Update: I purchased some new aluminum, Eckart 5413 H Super Pyro Military Grade German Dark Aluminum Powder, and it works perfectly. I made 2 grams and ignited it in an open paper cup. Wow!! I now feel I can try crossettes and shells with small reports. Thanks for everyone's input! 1
caddis Posted September 15, 2015 Posted September 15, 2015 I'd like to run this 70/30 FP mixing method past you pros and get your feedback. Quick background, I've handled over 20 types of explosives professionally (legally) during my employment (no detonating), however, never mixed components. Been enjoying pyroing for several years now using mostly BP and some FP. I'm fully aware of the dangers of FP having handled it before. I use the diaper method mixing small quantities at a time (1-2 g) and use all the precautions mentioned many times here. My primary work is 1.75" mortars with salute and some inserts (no metal yet). I decided to try a new, safer mixing method. After weighting the A and the K, I put them unmixed in the paper or plastic shell (fuse inserted and sealed before mix is put in). I tape them up as a finished product would be so now there is no chance of any static. I then use my reloading vibrating tumbler with the walnut media removed, placed in a safe place and let it run for about 5-10 mins. Before this I I used a small plastic sealed container with about 1g to see how it mixed and after 5 minutes it had a consistent color and appeared to be mixed pretty well. In addition to the shell, I also filled a pre-fused tube, plugged with the unmixed FP as a second test. Tested the finish products and both had a great solid report. I feel this method has reduced the risk of static caused detonation dramatically! Am I overlooking any safety issues or missing anything using this method? 1
FloridaCracker Posted September 16, 2015 Posted September 16, 2015 That is called the binary method and is widely used. I believe PGI requires it if you mix flash at the convention. The tumbler isn't necessary but it likely can't hurt to do so. Just handling the shell is enough to sufficiently mix it. If using plastic and not pasting the shell just roll it back and forth a couple times. A little empty space in the shell is necessary for mixing to occur. 2
caddis Posted September 17, 2015 Posted September 17, 2015 Thanks for the info Floridacracker. This means more enjoyment and less stress working with this stuff for my needs.
OblivionFall Posted September 24, 2015 Posted September 24, 2015 Thanks for the info Floridacracker. This means more enjoyment and less stress working with this stuff for my needs.The method you provided is very smart if you figured it out yourself. Took a lot of pyros to think about the idea. Make sure you keep space in the shell for it to mix. I don't see why mixing it with your rock tumbler like you said would be that bad of an idea.
caddis Posted September 26, 2015 Posted September 26, 2015 Yes, there's lot of space in these small shells as I only use enough FP to get a good break for my inserts which are just falling leaf, crackling fuse, etc. (newbie effects). When I progress and learn to make stars, I'll use bigger shells. Actually, with the vibrator tumbler, I suspect you probably could mix in a confined space since it's an intense shaking rather than tumbling but I don't have any applications to test this. On a side note, as mentioned in my original post, I've handled explosives before and I can't believe the crazies on Youtube. It's full of the, "Hold my beer and watch this crowd." I'm an older guy and learned years ago, if you want to learn something new the right way, learn from someone who knows a lot more than you, preferably a pro. I discovered APC recently and this is the place to "WATCH AND LEARN" the right way. An explosive instructor once told me, "Don't expect a second chance if you make a mistake."
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