taiwanluthiers Posted July 5, 2012 Posted July 5, 2012 I made some black powder yesterday with a ball mill... this is the burn test.Burn starts somewhere around 3s and ends before 4s, less than half a second. Used 75 Potassium Nitrate, 15 airfloat willow charcoal, and 10 sulfur. Ball milled 75 potassium nitrate + 5 charcoal, then 10 charcoal and 10 sulfur. The resultant powder was combined with screens and then 5% dextrin was added and the powder was slightly wetted and pressed through a screen. The finer rice was separated out and tested here, while the coarser ones are placed elsewhere for something else...
Mach25 Posted July 10, 2012 Posted July 10, 2012 I made some black powder yesterday with a ball mill... this is the burn test.Burn starts somewhere around 3s and ends before 4s, less than half a second. Used 75 Potassium Nitrate, 15 airfloat willow charcoal, and 10 sulfur. Ball milled 75 potassium nitrate + 5 charcoal, then 10 charcoal and 10 sulfur. The resultant powder was combined with screens and then 5% dextrin was added and the powder was slightly wetted and pressed through a screen. The finer rice was separated out and tested here, while the coarser ones are placed elsewhere for something else... I did basically the same thing only used 2% redgum with Alcohol worked great. I only ball milled for 3 hours each mix. Looks good
pyrojig Posted July 10, 2012 Posted July 10, 2012 One test of efficiency is to see how much dross or solid material is left behind after the burn. The more solid= less efficient . The goal is to get a simi-clean coco stain left after burning, that has little to no solids left behind. It should be able to burn on a piece of paper w/o igniting it. I find that the charcoal is a variable in these tests and its particle size needs to be airfloat .
taiwanluthiers Posted July 10, 2012 Author Posted July 10, 2012 One test of efficiency is to see how much dross or solid material is left behind after the burn. The more solid= less efficient . The goal is to get a simi-clean coco stain left after burning, that has little to no solids left behind. It should be able to burn on a piece of paper w/o igniting it. I find that the charcoal is a variable in these tests and its particle size needs to be airfloat . Like this? (no solids left behind, some blackening of the paper and little holes burnt into the paper)
Mumbles Posted July 10, 2012 Posted July 10, 2012 With that much blackening and burning, it still doesn't look like great powder. The burn test looks alright though. Possibly a little too sparky.
Potassiumchlorate Posted July 10, 2012 Posted July 10, 2012 Hm, I did the "newspaper test" too now, just to compare, and even my "4FA" leaves almost as much black on the paper as taiwanluthiers'. My ballmill is very good, so I guess it's the PITA humidity here, that makes the potassium nitrate and charcoal moist and hard to integrate
taiwanluthiers Posted July 10, 2012 Author Posted July 10, 2012 I dont know what is a great powder because that is as good as I can get it. It works well as a lift powder for star guns, and it burns as fast as the 4fg goex I had. The humifity is very high here so it could be that they can not integrate that well...
Potassiumchlorate Posted July 10, 2012 Posted July 10, 2012 Mine works too, but I realise that others have more powerful stuff. It's humid as hell here too. Yesterday I discovered that my magnalium smells a bit of ammonia, and that is supposed to be way more resistant to moist than magnesium. My magnesium doesn't smell anything, though. All new Mg is put in airtight glassjars to protect it.
bob Posted July 10, 2012 Posted July 10, 2012 really there are a lot of things you can change one that makes a BIG diffrens I find is charcoal some times willow just does not cut it and of course ball milling you want to ball mill it for at least 24 hours taking a little bit out ever hour or so and then after the 24 see which one is best getting the powder to wet in the screening part (wet and then screen) can make it burn slow to and of course this two piece milling is going to make it slower too drying it faster can help to (not really fast) like one a hot day in the shad with a good breeze (don't put in the sun)it should not burn through the paper at all what mesh did you burn (large stuff like 4 mesh burns slow and makes really bad lift for most shells (bigger ones must use larger mesh) it took me months to get my powder burning like it is know it's not some thing you get perfect in a weekbob
dagabu Posted July 10, 2012 Posted July 10, 2012 really there are a lot of things you can change one that makes a BIG diffrens I find is charcoal some times willow just does not cut it bob Interesting... I find willow (any kind) to be faster then pine which has become somewhat of a the bench mark for BP. -dag
Potassiumchlorate Posted July 10, 2012 Posted July 10, 2012 (edited) This latest BP is pretty fine. It passes through a 10 mesh kitchen strainer and is retained on a 40 mesh kitchen strainer. I mill it for 3 hours at ~85 rpm. I use 6 kilos of brass media for 1 kilo of composition. But maybe 6,12 or 24 hours would make a much faster powder. I know some people mill up to 60 hours, but that seems almost absurd. Edited July 10, 2012 by Potassiumchlorate
dagabu Posted July 10, 2012 Posted July 10, 2012 This latest BP is pretty fine. It passes through a 10 mesh kitchen strainer and is retained on a 40 mesh kitchen strainer. I mill it for 3 hours at ~85 rpm. I use 6 kilos of brass media for 1 kilo of composition. But maybe 6,12 or 24 hours would make a much faster powder. I know some people mill up to 60 hours, but that seems almost absurd. Wow! An hour max for me. 100% will pass a 60 mesh in that time and 90% through a 100 mesh screen. -dag
Mumbles Posted July 11, 2012 Posted July 11, 2012 I assume he's talking about material that has been granulated after it comes out of the mill.
Potassiumchlorate Posted July 11, 2012 Posted July 11, 2012 (edited) Haha, yes, I mill, wet with a little bit of water+alcohol, press pucks, dry them, crush them and sieve them. My BP is airfloat when it comes out, so I wonder where it can be wrong. I also use willow charcoal from FREAKYDUTCHMEN. It's awesome for H3 but doesn't seem as good for BP. One funny thing is that BP made with it smells exactly like BP in Chinese firecrackers used to do. Maybe I shouldn't press but instead add 2% of SGRS, wet it, make a ball and just granulate it in a colliander. I think Ian von Maltiz wrote that pressing makes the powder more uniform in performance but not faster. Update: I just tested some Triple Seven, which is a very fast KP substitute for BP. It burned the paper just like the BP did. Maybe that test isn't so reliable anyway. Edited July 11, 2012 by Potassiumchlorate
taiwanluthiers Posted July 13, 2012 Author Posted July 13, 2012 I made some Palownia... I am impressed with it so far. Newspaper test attached. On the left is Palownia charcoal, on the right is BBQ charcoal made as a comparison of how bad things can be!
Potassiumchlorate Posted July 13, 2012 Posted July 13, 2012 (edited) That was fast, but I don't trust the "newspaper test" anymore. Triple Seven is a fast powder, KP based and without sulfur. Yet it burns the paper about as much as BP does. Edited July 13, 2012 by Potassiumchlorate
taiwanluthiers Posted July 13, 2012 Author Posted July 13, 2012 Well, I am not sure what's a better way of testing the performance of the powder. Slow powder has its place though, like priming stars. I used to find these palownia wood everywhere and because the wood is very soft and light, I could find very few use for them... it just isn't good mechanically and it gives me the impression that they're cheap. So now the only use I've found for these cheap but crap wood is making high performance black powder!
Potassiumchlorate Posted July 13, 2012 Posted July 13, 2012 What I meant is that the "newspaper test" doesn't seem like a proper way of testing the burning speed.
Mumbles Posted July 13, 2012 Posted July 13, 2012 To me it tests both speed and cleanliness of burning. It is true that not all fast powders are clean burning, so perhaps it is not the end all test. I do generally prefer actual applicable tests like using baseballs or some other sort of projectile to test powder.
Potassiumchlorate Posted July 13, 2012 Posted July 13, 2012 If I don't start making much more shells, I have BP for years, although not top performing. Would be interesting to tune it up, though. More and more I think that it shouldn't be pressed but be in the form of pulverone. And more charcoal than 15%, unless it is absolutely top performance charcoal. And not less sulfur than 12%.
pyrojig Posted July 14, 2012 Posted July 14, 2012 (edited) To me it tests both speed and cleanliness of burning. It is true that not all fast powders are clean burning, so perhaps it is not the end all test. I do generally prefer actual applicable tests like using baseballs or some other sort of projectile to test powder. This is good advise . I too dont consider this the end all test either. It is merely a test , and tells if the powder burns clean and fast. I use paper for printers. It is thicker than newspaper. The cleaner and faster tests where based against Goex fff and ffff Black powder. My paulownia is superb as well , as it surpasses anything I have ever put against it (B.P.) . Willow is hot stuff, and poplar as well. Both prove to be very fast, commonly faster than commercially available Geox. Super fast Powder doesnt always mean better. Too fast and your hard work gets smashed or blown to pieces .To slow, and your gonna want running shoes to dodge a shell that plopped out of the tube 10' up. The mortar/ baseball test has proven the most effective and reliable test of them all. Gas -output is the key , some powders give off larger quantities of gas when burned. This = better lift and break . Some dirty burning powders are great and awesome performers !!! dont let this test dictate your views. Put the mortar/ baseball test to use for a better idea of its power. Paulownia is good for both speed and gas-output. It contains a high carbon content, which I'm sure contributes to is fuel value. Edited July 14, 2012 by pyrojig
taiwanluthiers Posted July 14, 2012 Author Posted July 14, 2012 The problem with Paulownia is that the wood is very light while taking up a huge volume, so one plank yields 80g of charcoal when finished (size 1.4x80x100 cm) I will have to readjust the ball milling amount to account for the increased volume.
pyrojig Posted July 14, 2012 Posted July 14, 2012 (edited) The problem with Paulownia is that the wood is very light while taking up a huge volume, so one plank yields 80g of charcoal when finished (size 1.4x80x100 cm) I will have to readjust the ball milling amount to account for the increased volume. LOL ....This is true !!! I was amazed at the volume it takes up!!! Now, this is a very good thing when building shells that have need of lots of burst. It takes up more volume , and I have burst shells with just paulownia bp coated hulls. It is truly a good burst. Edited July 14, 2012 by pyrojig
Potassiumchlorate Posted July 14, 2012 Posted July 14, 2012 What do you think about the ratio of the components? According to Ian von Maltiz the "Watson formula" ("standard" 75:15:10) is not optimal, especially not for lifting display shells. The question is whether the "PGI formula" 74:14:12 or the "Ulrich Bretscher formula" 100:18:16 are optimal either. Especially Bretscher's formula is for muzzle-loaded firearms, not display shell lift, although very similar to the "PGI formula". How much should the composition be changed depending on the type of charcoal, given that the potassium nitrate and sulfur are of high quality?
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