Apollofrost Posted March 12, 2008 Posted March 12, 2008 Yesterday I picked up a harbor freight rock tumbler then drove down to a local scrap yard to pick up some grinding media. I figured it would make a nice first ball mill. Soon I'll be picking up some non-sparking media and some chemicals to make my own bp. Anyways while I was at the scrap yard I saw great big bins of what the sales person said was aluminum. It looked like the turnings you get when you take a lathe to a bar. He said it was from a local factory specializing in aerospace and lenses. He also told me that it was 1.50 a lb. Figuring I had nothing to lose I purchased a pound or two, loaded it up with my grinding media, then went home. This morning I threw some of it in the makeshift ball mill and when I get off of work I'll see how it's doing. What I want to know: Is there any danger of a reaction if I use steel media? I'd hate to have a speck of rust cause a thermite reaction in my new mill. Is there any way I can make sure it's aluminum or assay the purity? What would be the optimal way to grind it down?
justanotherpyro Posted March 12, 2008 Posted March 12, 2008 There are a lot of different answers. The only real success that I have had as far as home ground Al is throwing some foil into my ball mill (which at the time was the same one you have) with some 1" screws and stainless steel media. It takes many many days though to get a fair amount of Al powder but it does work. Make sure when you grind down Al in a ball mill to open the jar up every few hours to allow the metal to oxidize and prevent it from becoming pyrophoric ( spontaneous ignition upon exposure to oxygen ) Another possibility is making Magnalium but that in itself is a pretty big project.Something that a lot of newer pyro's do is filing down Mg or Al but its very time consuming. One more that I can think of is using something like a dremel tool which is just a faster way of filing down the Al at the cost of contaminating it with whatever grinding material is on the disc. As far as safety is concerned, thermite has a high activation energy so chances of it forming from the small amount of rust present and then going off are on the slim side. Just to be safe try and get the rust off of your media though. I know of one instance where someone had powdered Mg in a ball mill which spontaneously combusted when the media hit it, so it doesn't hurt to be as safe as possible. Hope this helps.
Apollofrost Posted March 12, 2008 Author Posted March 12, 2008 The milling seems to be going quite well thus far, but the results are less than uniform. Some of the powder is so fine it's little more than dust and some of it's in larger flakes. I've been adding a few grams at a time then waiting for it to be ground down before I add more. Can you folks think of anything an amateur could use the fine aluminum and the flake for? Don't worry, I'm going nowhere near flash powder. On a side note, the ball mill is currently off because SWAT is on my block complete with dogs and body armor. One of my housemates came up and told me. I thought he was joking, but apparently not. I was freaking out and so where my housemates, but it turned out that they were busting the guys two houses down for something drug related. I didn't get close enough to ask too many questions because I was weary of the dogs, but I got some nice shots with my telephoto. I'm off to buy chemicals, seems there's a local supplier not that far from me selling kno3 in 50lb bags for $22.
justanotherpyro Posted March 12, 2008 Posted March 12, 2008 That is a really good deal for KNO3 just as long as its pure. The bag that I bought years ago actually says " Potassium Nitrate " on it. It was the water soluble kind (non prilled) which is really nice. Took me a few years but im going to need to get another 5olb bag here soon enough. As far as the Al goes all you can really do is just screen out the super fine powder, I use an old laundry lint trap that is a fine mesh. It can be used for various things. Meal n metal comps, there are some "brilliant" star compositions that use Al as the source of fuel, it works pretty well with a bp prime to make it hotter ( I like using the home ground Al instead of wasting store bought Al which is harder and harder to get). I made quite a few Greenmix/Al fountains when I first started years ago. Those were always cheap fun and pretty cool too.
Apollofrost Posted March 13, 2008 Author Posted March 13, 2008 Unfortunately the clerk mistook kno3 for urea(not my thing) but they did have sulfur fungicide and granulated kno3 stump remover. Oh, any thoughts on mesquite charcoal for bp?
mormanman Posted March 13, 2008 Posted March 13, 2008 Mesquite, I think would suck. Its not bad per say but its not powerful to lift anything I would think. I looked for info on it (glanced on the test page, some of you guys know what I'm talking about) and didn't see anything. I hear from some Newspaper works good you just have to add likeKNO3 75S 8C 17 or something like that.
justanotherpyro Posted March 13, 2008 Posted March 13, 2008 Even really shit BP can be made into good stuff. I make a half kilo batch of really crappy BP every once in a while with some really crappy C ( generic hardwood charcoal that turned out to suck ) to make my blackmatch with. The crusty stuff left over on the side of the container after drying is very fast stuff. Slow BP can be turned into good BP via corning, even better if you press it into a puck. As for newspaper C I have made 2 batches before and it was very fast. Just make sure when you cook Newspaper C though that you don't have any wax advertisements in there.
FrankRizzo Posted March 13, 2008 Posted March 13, 2008 Unfortunately the clerk mistook kno3 for urea(not my thing) but they did have sulfur fungicide and granulated kno3 stump remover. Oh, any thoughts on mesquite charcoal for bp?It's not very good for BP, but does make nice BP-based stars. I suggest ordering 8# of willow (35.99 w/free s/h) or 20# of alder (16.99 + s/h) lump from customcharcoal.com. If that's too expensive or bulky, order a few lbs of the 80-mesh stuff from Discount Pyro. The stuff they sell is the same mixed-hardwood crap you'd get from Skylighter, but the 80-mesh seems to have much more actual charcoal content as compared to the airfloat (lots of minerals and crap) and performs almost twice as well. If you're ball-milling the stuff, it doesn't really matter what form your charcoal is in.
Apollofrost Posted March 14, 2008 Author Posted March 14, 2008 A burn test with some bp meal 75kno3 15c 10s loosely packed into a 3/8 in cardboard tube revealed that the mix burned nicely and left some three foot sparks, but that could have been from granules of unburned bp lighting as they were expelled from the tube. I threw in some al flakes from the tumbler but got few extra sparks. However I did get one that burned with a blue tinted white flame. I'm at this point unsure if it was even aluminum in the bins after all. Either way I won't be putting it in my tumbler as the sharp bits were wreaking havoc on my liner. I think I'll be focusing on rocketry with some occasional delving into fountains, any suggested projects? Right now on my to do list are: Mini Sugar Rockets Visco rockets Mini bp rockets 50g rockets 100g rockets Rockets w/ payload Stars of different colors Mini-fountains Fountains that shoot stars Rockets w/ tails Any suggested reading for how to do fountains besides passfire?
Bonny Posted March 14, 2008 Posted March 14, 2008 Any suggested reading for how to do fountains besides passfire? You could try these: http://www.pyrosociety.org.uk/forum/index....58&hl=fountains http://www.pyrosociety.org.uk/forum/index.php?showtopic=473 http://www.pyroguide.com/index.php?title=Fountain
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