FlareLauncher Posted April 2, 2017 Share Posted April 2, 2017 I understand that the TYPE of charcoal used is very important in making BP. Good enough, being hard headed I had to try for myself and made some really piss poor BP using carbon. My question specifically applies to dark Al. Is the TYPE of charcoal that I add to the Al to retard the oxidization during the grinding / ball milling process critical? I have a supply of Carbon I would like to use up. Is it appropriate for Al grinding?I have tried to research the sites archives, and can find no definitive answer. Likewise, what is the correct ration for Charcoal to Al during ball milling? Thanks, Bill Link to comment Share on other sites More sharing options...
lloyd Posted April 2, 2017 Share Posted April 2, 2017 The carbon in so-called "black aluminum" was originally from the paper backing of the wrapping foil used to make the product. But true "blackhead aluminum" is not called that for anything even remotely associated with its carbon content. I excerpt from an article by Mike Swisher on Dan Cregan's Wichita Buggy Whip site: "German black aluminum (Hummel "black head," so called because the head of the drum is painted black) is supposedly made bystamp milling foil to which a quantity of carbon black is added. It is a dark grey powder (about the color of antimony sulphide), and relatively dense compared to other flake aluminums. German "Blue head" is intermediate between German black and U.S. No. 809, and can be approximated by a mixture of half-and-half German black and No. 809. German "Yellow head" is a bright grade. These were all still in Hummel's catalogue the last time I looked. An old timer told me there once was a "Red head" grade, intermediate between blue head and yellow head, that was good for tremalons. All of these are or were made either by Gloria or Eckhardt, I think." More can be found here:http://www.wichitabuggywhip.com/fireworks/aluminums.html 1 Link to comment Share on other sites More sharing options...
FlareLauncher Posted April 2, 2017 Author Share Posted April 2, 2017 Lloyd, what an excellent answer! Thanks for clearing that up for me. Bill Link to comment Share on other sites More sharing options...
DesertCatUSN Posted June 17, 2017 Share Posted June 17, 2017 What about activated charcoal (often from coconut shells) as a carbon source, if you powder it? I know it starts out 'activated' because it absorbs impurities in all of the internal pores. If it's powdered fine enough, does that get rid of all the pores, or does having some pore space in the charcoal help bind the sulfur and Nitrate together, making a better black powder? Thanks, Roger Link to comment Share on other sites More sharing options...
MrB Posted June 17, 2017 Share Posted June 17, 2017 I believe activated charcoal is "overcooked" for our purposes. 1 Link to comment Share on other sites More sharing options...
lloyd Posted June 17, 2017 Share Posted June 17, 2017 MrB,Yes. It has had ALL the volatiles burnt out, specifically for making it 'micro-porous', so it will adsorb and absorb various chemicals. That makes it not nearly as energetic fuel as properly-cooked charcoal. It's not really suitable for pyro work, although some have made long-hanging sparks from it (too-long hanging, FWIW). Lloyd 1 Link to comment Share on other sites More sharing options...
DesertCatUSN Posted June 17, 2017 Share Posted June 17, 2017 Bummer. Thanks! So I'd be better off taking charcoal briquettes, breaking them up, then blending the chunks into powder? Definitely much cheaper. Or is the source wood not the proper type? And is there ever a problem with having the powder too fine? I should probably look that up, but it seemed pertinent to this discussion. Thanks again! Link to comment Share on other sites More sharing options...
lloyd Posted June 17, 2017 Share Posted June 17, 2017 Cat,I don't think you can mill charcoal "too fine", unless you plan to use it for extended sparks. In that case, it's important to screen-grade it to specific sizes ( 40-mesh, 80-mesh, 120-mesh, etc). But charcoal briquettes are not a good source. They are usually made from mixed hardwoods, but also contain binders and inerts (like clay) that can interfere with their use in pyro. I have found a use for briquette charcoal in long-hanging willows... but that's about all. If you wish to use commercial charcoal, use "natural chunks". Even then, they're usually over-burnt, and not as active as charcoal you can EASILY make in your own TLUD cooker (preferably from Cedar chips from the local home store). Lloyd 1 Link to comment Share on other sites More sharing options...
DesertCatUSN Posted June 17, 2017 Share Posted June 17, 2017 Lloyd, Very helpful! Thank you, Imappreciate it. Roger Link to comment Share on other sites More sharing options...
Arthur Posted June 18, 2017 Share Posted June 18, 2017 Charcoal used for BP and like compounds needs the cellular structure of the tree from which it came, hence the reason why people swear by specific charcoals for specific purposes. Milling aluminium has a self limiting particle size -after some milling the particles tend to re-agglomerate and never get any smaller. To change this a solid lubricant is added to keep the aluminium milling without agglomerating. It's purported that one process involves using fine Al coated tissue paper which is charred to carbon, but I've never seen reliable evidence. The bright flake Al that I have seen is apparently oily, is it made into flake in an oil lubricant, -mineral or vegetable??? It may be just a coincidence that charcoal/carbon is good for BP and carbon/graphite is a good solid lubricant. I did see once (on the web) a BSc level thesis on the production of pyro aluminium from drink cans (iirc from an establishment in SE Asia). They achieved product of sufficient fineness by milling with steel balls under oil for periods from a week (168 hours) to several weeks. Then some oils contain sulphur so you get more incompatibilities. 1 Link to comment Share on other sites More sharing options...
DesertCatUSN Posted June 18, 2017 Share Posted June 18, 2017 Thank you Arthur. That helps me see more of the big picture, just have to open the other eye now. Roger Link to comment Share on other sites More sharing options...
OldMarine Posted June 18, 2017 Share Posted June 18, 2017 I read that the lubricant used in flake Al is stearin. Smells like it's right! Link to comment Share on other sites More sharing options...
FlareLauncher Posted June 18, 2017 Author Share Posted June 18, 2017 I read that the lubricant used in flake Al is stearin. Smells like it's right! Maybe I wasn't clear - Im asking about what difference it would make to use carbon instead of charcoal in my dark aluminum milling. Link to comment Share on other sites More sharing options...
FlareLauncher Posted June 18, 2017 Author Share Posted June 18, 2017 Charcoal used for BP and like compounds needs the cellular structure of the tree from which it came, hence the reason why people swear by specific charcoals for specific purposes. Milling aluminium has a self limiting particle size -after some milling the particles tend to re-agglomerate and never get any smaller. To change this a solid lubricant is added to keep the aluminium milling without agglomerating. It's purported that one process involves using fine Al coated tissue paper which is charred to carbon, but I've never seen reliable evidence. The bright flake Al that I have seen is apparently oily, is it made into flake in an oil lubricant, -mineral or vegetable??? It may be just a coincidence that charcoal/carbon is good for BP and carbon/graphite is a good solid lubricant. I did see once (on the web) a BSc level thesis on the production of pyro aluminium from drink cans (iirc from an establishment in SE Asia). They achieved product of sufficient fineness by milling with steel balls under oil for periods from a week (168 hours) to several weeks. Then some oils contain sulphur so you get more incompatibilities. I have been milling cheap (uncoated) tinfoil that has been blended to sand size in my rock tumbler. I dump it out daily and sift it to 400 mesh. The rest goes back into the ball mill. It seems to be working real well, and I have been using Carbon. I just wondered it if worked better - or worse - than charcoal. Link to comment Share on other sites More sharing options...
OldMarine Posted June 18, 2017 Share Posted June 18, 2017 Sorry FL, I didn't read closely enough. I regret that I have no information on milling metals. My reading has led me to avoid it at all costs. Lloyd and August have both had bad experiences and both are far above my paygrade on the pyro scale. Be careful and good luck. Link to comment Share on other sites More sharing options...
Arthur Posted June 18, 2017 Share Posted June 18, 2017 Wikipe -"In fireworks, stearic acid is often used to coat metal powders such as aluminium and iron." You may well be right OM, various stearates are used as low melting lubricants. Link to comment Share on other sites More sharing options...
FlareLauncher Posted June 18, 2017 Author Share Posted June 18, 2017 OldMarine, No harm, friend. Im new to this myself, and treat it with maximum respect. ITs simple, NOT easy - but then, so is screwing up... Link to comment Share on other sites More sharing options...
Arthur Posted June 18, 2017 Share Posted June 18, 2017 Charcoal is only one form of graphitic carbon -you certainly don't have the tetrahedral form (diamond!). Carbon may be a good solid lubricant for Al foil -which form is better I have no idea, start with a cheap one! 1 Link to comment Share on other sites More sharing options...
lloyd Posted June 18, 2017 Share Posted June 18, 2017 FlareLauncher said:" I dump it out daily and sift it to 400 mesh."---------------------------------------------------------------- Really? You actually OWN a 400-mesh screen? Where'd you get it? (Please?) I already know where to get it, but I've tried screens under 200-mesh, and find them (basically) impossible to use in any sort of productive manner. Lloyd Link to comment Share on other sites More sharing options...
FlareLauncher Posted June 19, 2017 Author Share Posted June 19, 2017 Lloyd, It was a piece of scrap I picked up from work. nylon mesh, #400. I cut out the bottom of a plastic bowl and hot glued it to the outside. I screen out my marbles (those I haven't lost ) with a pasta colander. The rest all goes into a 200 mesh screen. What passes there goes to the blue bowl with the #400 screen in the bottom. Whatever passes there is #400 and goes into a small jar. ALL of the rest of it goes back into the tumbler for another ride. I wear mask (NIOSH) and latex gloves for the operation. Usually I get about a tablespoon of the #400 per 24 hours tumbling. I NEVER tumble longer, as I hate surprises. I'd be happy to send you a snippet of the nylon screen if you would like it. Just PM me your address. Bill Link to comment Share on other sites More sharing options...
lloyd Posted June 19, 2017 Share Posted June 19, 2017 Bill,Thanks, but no. I've never found a need to screen any pyro chemical (in commercial production) through anything finer than 80-mesh. I've tried it, and the results aren't worth the difficulties. Lloyd 1 Link to comment Share on other sites More sharing options...
Recommended Posts