JCrewPyros Posted March 25, 2008 Posted March 25, 2008 I have intro'd myself and stated I am new to the community and hobby so please play nice with me (= The question that I have is a newbie question... When pressing the BP Pucks is there a cut off for pressure needed? I am asking this because instead of a regular hydro jack/pump we have a machine that can Press/Bend 1/2 inch steel... When is too much toooo much? Can we over press the pucks or would we have more concern on damaging the puck die? We haven't made BP nor have the stuff to do it yet as we will be learning to make it this weekend at the PAT event here in Texas... But I wanted to get this question answered before attending... Thanks!
InRainbows Posted March 25, 2008 Posted March 25, 2008 I think it would be really useful to post a picture of the press, to see if it looks like something you could use in pyrotechnics. I've never heard anyone say anything about over pressing, but depending on the piston jack you should get different puck diameters based on what I've heard. I think it's somewhere around 6 tons for a 2 inch puck, around 12 tons for a 3 inch puck. I think the optimal density to press it to is 1.7 grams per centimeter. I actually think if you "over pressed" it, it would work better . You'd have more dense pucks, which breaks up into denser powder.
qwezxc12 Posted March 25, 2008 Posted March 25, 2008 Most people refer to the 1.7g/cm as the standard. Some notes from "A Comprehensive Review of Black Powder" published by the Army Ballistic Research Lab at Aberdeen Proving Ground suggest otherwise. I'm sure the actual charcoal composition is far more of a variable than the extra pressure:http://www.apcforum.net/files/BPburnrates.jpg The pdf is available at Dan Regan's page...Danny / Lady Kate's site is highly recommended reading BTW. As an aside, I have no dog in this fight; all of my lift is pulverone now. I did not notice enough performance difference to warrant the extra effort of pressing / corning.
Mumbles Posted March 25, 2008 Posted March 25, 2008 I cannot for the life of me get the page to come up, but some very basic unscientific testing I did gave the best results at 1.7g/mL. I tested riced, 1.4. 1.7, and 2.0. 1.7 came out the best with 1.4 close behind. Despite the larger grain size, the pressed material gave better results than the simply riced. There are a lot of factors involved. From what I've seen, and others have seen it seems that for some reason pressing seems to increase performance. Might have to do with increased intimacy, KNO3 leaching, rougher edges, etc. A lot of factors play a role. I think the biggest advantage to pressed BP is that it is stronger and more consistent. It is harder and thus less likely to break during handling or storage. This will allow for more consistent performance.
JCrewPyros Posted March 25, 2008 Author Posted March 25, 2008 I cant get a picture today but just to give you the scale of this machine(Not a small machine at all)... Its about 15 foot wide and 9 foot tall... they use it to bend large plates of metal to make Frac Tanks... If you dont know what those are they are huge metal containers say 50 foot by 15 foot that hold salt water for oil drilling operations... The machine is massive... they have 2 of them... along with about the same size machines that shear/cut huge peices of flat metal up to 1/4 thick... Needless to say I could very well add WAY more pressure than needed... thats why I was asking if you could over press pucks... *EDIT* Here is the link to the press... its the one on the left (= BTW we can fabricate a die to fit it to make 10-20 pucks at a time... http://www.fmsweb.com/Atlantic01.htm
TheSidewinder Posted March 25, 2008 Posted March 25, 2008 His main page loads for me, but clicking on the PDF locked up my browser. Twice. Fair warning to anyone who wants that PDF: RIGHT-CLICK and SAVE-AS to your desktop or whatever, then open with Acrobat Reader or similar. JCrewPyro - My god, you could probably press diamonds with that monster! Yeah, definitely overkill, lol. Everything that's been said so far should be helpful. As was said, the target density for your BP is 1.7 grams per square centimeter, but I know there's wide variance in what people make. Personally, I just mill for 24 hours then "rice"** the result. **Ricing - many posts about it here already, I won't repeat them, but basically, add ~ 5% Dextrin to your milled BP flour, wet with ~ 10% alcohol/water, grate it through a correct-size screen, let dry. TS
Mumbles Posted March 25, 2008 Posted March 25, 2008 That should probably be grams per cubic centimeter sidewinder. Grams per square centimeter is a pressure unit. It should also be noted that a cubic centimeter is equivalent to a milliliter.
JCrewPyros Posted March 25, 2008 Author Posted March 25, 2008 Sidewinder: Yeah its huge... But thats the perks of having someone in the welding fabricating business (= Btw I have read every last newbie question post in the last 2 days so... lol I got the gist of most of the terminology and or abbreviations... Thanks for all your information... Glad to see a board with some life in it... (= Take care and be safe!
TheSidewinder Posted March 25, 2008 Posted March 25, 2008 Ooops. Yep, you're right. I was thinking the right term, But somewhere between brain and butt it got transmogrified. That's why I'm the code monkey and you're the Chemist. M
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