I'm going to copy a lot of what follows and condense it from a running thread I made on a gun forum I frequent but before I do:
I decided recently to try my hand at making real black powder. All I have ever used so far is Pyrodex. My every day carry piece is an 1851 Navy (.36 caliber) cap and ball and happens to be my most fun to shoot. Pyrodex runs me $20-25 a lb. Real black would be similar if I could find it near me, and exorbitantly priced if I had to have it shipped due to haz mat fee's. So it just seems logical that I should try my hand.
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Formula was KNO3 - 168 gr, C - 33.6 gr, S - 22.4 gr. Spectracide Stump Remover for kno3 (Labels and MSDS | Spectracide), Bonide 90% garden sulphur (http://www.bonide.com/lbonide/msds/msds141.pdf), Red Ceder charcoal.
This is just the components mixed into powder, did not mill, but thoroughly mixed after running through fine mesh. I have some I wet mixed that is drying waiting to be screened into grains. My main concern is identifying the residue.
Could it be from just not milling the ingredients fine enough? Or that 10% bentonite clay in the sulphur? Any constructive advice would be appreciated!
(Note: At this stage rough mixed, the screened fared no better than this next test)
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I improvised a morter and pestle using my shaving soap bowl and a screwdriver handle. Then I ground a bit for a while while watching a movie and without wetting and screening, ran the same fine powder through the same test. It seem to me from point of ignition to end of burn I have a 50% increase and much less residue, which I have read is KNO3 due to not having an "intimate" mixture.
Here is the second burn test.
Not wanting to shell out the big bucks for a good mill, or waste money on a cheap one, I have a drill press like the one in this video. Next time I go into town, I will be picking up 1/2" round and pipe insulation and PVC/end caps and making this mill:
https://www.youtube.com/watch?v=I9S2fToAmWA Video is 3 mins.
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(At this point I made the mill and ran it in that)
Much much better.
Built the ball mill, tweaking it currently. This is after 1 hour of milling with .36 caliber round balls, 1 water bottle full, in a 4 inch pvc pipe with slip caps, bout a foot long.....
Ill mill it some more, then wet and screen it. Lookin good, I think!
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Success!! Milled it till it stuck together on it's own, screened it, wetted it to get it to stick together really well, Then screened with window screen last nite. Seemed fairly dry so I re-screened it with window screen this morning to get uniformity of granules since some was a bit over wet last nite and globbed up.
I used paper this time so you could get an idea of granule size.
This is the tail end of second screening, the lager granules. Once this dries I'll be ready to test fire!
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Next I'll load some up at some point and try to get a video of me firing it. Also to note, Normal percussion caps work fine on pyrodex, but the red plastic caps for toy cap guns didn't even scare it, let alone set the Pyrodex off. Never got even 1 chamber to fire no matter what I tried.
I am hoping and expecting the real black powder to be able to be set off with toy cap gun caps, since it has a MUCH lower ingition temperature and is more sensitive by far than the pyrodex. This would also be a huge savings as toy caps are dirt ceap and real caps run me about 6.99 per 100. And rather than the $20-25 a lb if I get my chems from ebay, the purity will go up and my final cost should be around $2.47 a lb or just a measly 10% of what I pay now.
Hope ya'll enjoyed, add a new hobby to the list for me, lol !