Mumbles Posted October 15, 2008 Posted October 15, 2008 I heard alcohol washing will remove the coating, but that may just be for the stump remover stuff. A simple recrystalization should probably do the trick, as the coating is probably a carbonate.
Richtee Posted October 15, 2008 Posted October 15, 2008 I heard alcohol washing will remove the coating, but that may just be for the stump remover stuff. A simple recrystalization should probably do the trick, as the coating is probably a carbonate. They coat it to? Prevent pyro usage? I am a bit ignorant...a carbonate coating is water soluable I assume, otherwise it would not work as fert or stump remover. So, they go to the expence of coating it when a simple dissolving and drying will improve it? But the carbonate will still be in there then, but what- just not COATING it? Sorry to be such a PITA, but I am curious.
tentacles Posted October 15, 2008 Posted October 15, 2008 The purpose of the coating is to keep the prills free-flowing, so that they perform as expected in agricultural equipment. With the coating, when they get damp instead of forming a rock hard clump, the clumps can be easily broken up with a light squeeze. Prills work just fine in fireworks - I'm moving through a bag of prills at the moment and it's made good glitters, BP, charcoal stars... and it burns purple in a flame test.
Mumbles Posted October 16, 2008 Posted October 16, 2008 Yep, I have no problems with prills either. Good thing too because I have a quarter ton of it. The stump remover, at least some of it, is coated with sodium or potassium hydroxide. I helps to accelerate the absorption, or rotting, or whatever it is that it actually does.
GearGuy2001 Posted October 18, 2008 Posted October 18, 2008 Yep, I have no problems with prills either. Good thing too because I have a quarter ton of it. The stump remover, at least some of it, is coated with sodium or potassium hydroxide. I helps to accelerate the absorption, or rotting, or whatever it is that it actually does.In regards to stump remover, the version that Walmart sells works well for sugar smoke bombs, If I recall correctly without referring to the label its 97.8% KNO3 and I believe it is what people refer to as prills. It costs about $5.50 for a 1lb Bottle.
Pyro55 Posted October 22, 2008 Posted October 22, 2008 The best deal on AL that I have found on Ebay was:6 kgs(=13.2 lbs), d50=3.21um, Aluminum Powder for $99.00 with free shipping.This stuff works as well as German or India Black for 70/30 and it was cheap enough to use for thermite. It is a very fine dust and I wouldn’t use it without a respirator. I made some exploding targets, using this AL. I mixed KClO4/ AL/S .They would deflag with a 22LR.
50AE Posted October 24, 2008 Posted October 24, 2008 I found this aluminium powder. Do you think it's really 4200 mesh ? I would buy it instantly. http://cgi.ebay.fr/1lb-Aluminium-Powder-42...p3286.m63.l1177
FrKoNaLeaSh1010 Posted October 24, 2008 Posted October 24, 2008 The best deal on AL that I have found on Ebay was:6 kgs(=13.2 lbs), d50=3.21um, Aluminum Powder for $99.00 with free shipping.This stuff works as well as German or India Black for 70/30 and it was cheap enough to use for thermite. It is a very fine dust and I wouldn’t use it without a respirator. I made some exploding targets, using this AL. I mixed KClO4/ AL/S .They would deflag with a 22LR. Do you remember the ratio you used to make the exploding targets? I used to use a kclo4/al/s ratio for flash all the time because the sulfur cuts down on weight needed of aluminum making it a cheaper comp and am wondering if it was the same. I dont have a .22 but if a .22 can set it off all the rounds I shoot will (.223, 7.62x39, .308)
Pyro55 Posted October 25, 2008 Posted October 25, 2008 Do you remember the ratio you used to make the exploding targets? I used to use a kclo4/al/s ratio for flash all the time because the sulfur cuts down on weight needed of aluminum making it a cheaper comp and am wondering if it was the same. I dont have a .22 but if a .22 can set it off all the rounds I shoot will (.223, 7.62x39, .308) I am not sure but I think the last targets were 64/23/13. My formulas and pyro lab are twenty miles away. I will check next time I am there. A few years ago I made some targets with KClO3/AL/S. They were much more sensitive.They would explode with a 600 fps 177 pellet rifle. I make the back of the target with 80 grit sand paper. My next project is AN/AL targets. If I can come up with a good formula, I will post.
WarezWally Posted October 25, 2008 Posted October 25, 2008 The best deal on AL that I have found on Ebay was:6 kgs(=13.2 lbs), d50=3.21um, Aluminum Powder for $99.00 with free shipping.This stuff works as well as German or India Black for 70/30 and it was cheap enough to use for thermite. It is a very fine dust and I wouldn’t use it without a respirator. I made some exploding targets, using this AL. I mixed KClO4/ AL/S .They would deflag with a 22LR. My mate got a few pounds of it, its rather good for the price
50AE Posted November 1, 2008 Posted November 1, 2008 I don't trust this guy with the 4200 mesh aluminium. He has no purchases, no comments, no evaluations yet. I'll wait and see if someone buys aluminium from him.
Swede Posted November 2, 2008 Posted November 2, 2008 I've bought a lot of stuff off eBay, but most of it is non-pyro related, or if it is, it is indirect, like a power supply for chlorate electrolysis. But I have bought both labware and once or twice, some chemicals, including aluminum. Now, when I sign in, I get an advertisement. Swede, need more Dark Pyro Aluminum? Or, how about some 24/40 Lab Glassware for Chemistry? Here's what's available on eBay RIGHT NOW! Kind of makes me cringe. There is no doubt that such stuff is tracked in some serious detail. It is up to the user to decide just how public he wants to be with this hobby.
50AE Posted January 11, 2009 Posted January 11, 2009 Just to warn you that the aluminium powder from fedse, that pretends to be 400 Mesh... http://cgi.ebay.co.uk/L-K-ALUMINIUM-POWDER...%3A1|240%3A1318 ...isn't really 400 Mesh, but maybe it's its average particle size. I just screened a batch with my 400 mesh screen and I got :-40 grams of powder lower than 400 Mesh (can't pass through)-68 grams of powder higher than 400 Mesh (can pass through)
WarezWally Posted January 11, 2009 Posted January 11, 2009 I got some "Eckhart 5481 super H" off that seller quite some time ago and I still have nearly all of it, my Indian dark performs much better that it (opposite to what I have read) so maybe something is going on?
50AE Posted January 11, 2009 Posted January 11, 2009 (edited) I got some "Eckhart 5481 super H" off that seller quite some time ago and I still have nearly all of it, my Indian dark performs much better that it (opposite to what I have read) so maybe something is going on? You may try to screen it and see. Here are some pictures : 400- Mesh Al powder on the left and 400+ Mesh Al powder on the right http://img440.imageshack.us/img440/5863/dsc04377xp4.th.jpg http://img229.imageshack.us/img229/8106/dsc04376hh8.th.jpg Edited January 11, 2009 by 50AE
Mumbles Posted January 11, 2009 Posted January 11, 2009 It's not pretending to be anything. It's accurately labeled. Well maybe not the finer than flour comment. When they give you a single particle size, IE 400 mesh or 38 micron, it's pretty safe to assume it's an average particle size. All metal particles have a size range. Even a -400 mesh metal(notice the minus sign), I'd still expect to have 5-10% that didn't pass. I'd trust a microscope much more than a screen. Screens this small are notoriously inaccurate.
Miech Posted January 12, 2009 Posted January 12, 2009 I got some "Eckhart 5481 super H" off that seller quite some time ago and I still have nearly all of it, my Indian dark performs much better that it (opposite to what I have read) so maybe something is going on?Are you sure it isn't Indian Black? I have seen many black aluminiums outperform 5413 H easily, just because they were not coated. This makes it way more reactive, but increases the sensitivity when used in flash, especially with nitrates or sulfur present. When I tested the difference the first time I was amazed too. A 0,5 gram pile of flash made with 5413 H did 'Whomp', while the same amount of flash with 8 um black aluminium litterally gave a loud bang.
WarezWally Posted January 12, 2009 Posted January 12, 2009 Fairly sure, it is finer than my Indian stuff. I leaning towards some sort of aluminium powder cut with lampblack but I could be talking out my ass for all intensive purposes here.
Swede Posted January 12, 2009 Posted January 12, 2009 Hmm, that's interesting, so the Indian is superior? I thought the Ekhart was supposed to rule. What is the black color anyhow? I've read so many different opinions - added carbon, a byproduct of processing, etc. Anyone know the reality of the black coloration? Is it really just added lampblack?
WarezWally Posted January 12, 2009 Posted January 12, 2009 In my experience Indian gives better reports and seems to be a tad faster, I'm fairly sure I could pick the two in a blind test using the aluminiums I have. Don't forget that Indian dark flake is just a description and not a brand name of any sorts, I'm sure there is more than one manufacturer pumping out barrels of the stuff.
psyco_1322 Posted January 12, 2009 Posted January 12, 2009 So last year I bought some 5413 H at the convention, being the first dark Al I bought, it was pretty good. This year I bought some from another guy, it may be labeled 5413 H Super though, not sure off hand, but it seems to have a noticable amount of coarse flakes in it. Just from the looks, its not as fine, its not really that hot either. Someone said that the Al meshes actually have change quite a bit over time, and the 5413 H you bought 5-10 years ago, is not the same crap you buy now days. Logically I would say the finer the Al the better. So the 5413 H is a coated Al? I believe the black color comes from the process used to make it. The way I understand it is that thin sheets of Al are baked in an oven until they become covered with an oxide layer and become brittle. It is then hammer milled? to a powder.
Mumbles Posted January 13, 2009 Posted January 13, 2009 All the flash grade aluminums are coated to some degree. If you look at some of the barrels or COA's it's right there. It's how they remain so reactive, less oxide coat, plus the particle size and shape. These particles are so fine if they were fully exposed to air they'd be mostly Al2O3. >92% Aluminum Psyco, I think you mean stamp milling. A hammer mill only works on brittle materials. I had always heard the paper backing was burned off after stamp milling, but I'm not an expert in flash aluminum. The paper backing was to make it more solid so as to not just reform into larger chunks again.
Pyro55 Posted January 16, 2009 Posted January 16, 2009 I have a bag of German Blackhead that I bought from Square Lake Enterprises several years ago. This weekend I will try to examine it and some new German Black under a microscope. If I can get a good photo, I will post. So last year I bought some 5413 H at the convention, being the first dark Al I bought, it was pretty good. This year I bought some from another guy, it may be labeled 5413 H Super though, not sure off hand, but it seems to have a noticable amount of coarse flakes in it. Just from the looks, its not as fine, its not really that hot either. Someone said that the Al meshes actually have change quite a bit over time, and the 5413 H you bought 5-10 years ago, is not the same crap you buy now days. Logically I would say the finer the Al the better. So the 5413 H is a coated Al? I believe the black color comes from the process used to make it. The way I understand it is that thin sheets of Al are baked in an oven until they become covered with an oxide layer and become brittle. It is then hammer milled? to a powder.
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