Baldor Posted July 23, 2017 Posted July 23, 2017 I'm having difficulties finding good media in Europe. I can only find aluminium ceramic, and after reading other threads, decided against it. I found one supplier for antimonium alloyed lead, but it's expensive, too big for my jars, and the shipping is still more expensive. Casting is out of the equation for now, I can get all the lead I need, but will be soft and I'm not in the mod for casting with 28ºC plus and high humidity. I thought about using fishing sinks, but are soft, and the hole in the middle will only help with cross contamination. I work with small bathes, 1300ml jars, about 100mm diameter. I can get 2m 10mm diameter AISI-304 stainless steel for less than 5€ plus shipping. Since I´m purchasing other materials shipping is not a problem. I can cut this bars to make cylindrical media, I will be wasting a lot of material with every cut, but it's cheap, and my time is free. What do you think? Will 20mm long cylinder be Ok, or can I make them longer? Should I get bigger diameter media, say, 12mm, for this jar?
lloyd Posted July 23, 2017 Posted July 23, 2017 For 100mm i.d. jars, about 12mm is close to optimum. Cylindrical media should be close to 'square' -- that is, the length should be about the same as the diameter. De-burr freshly-cut metal media by milling an abrasive for a time. Carborundum powder mixed with water works well. Charge the jar 1/2 full of media, and use only 1/8 volume of the jar charge of the grit (a normal 'material charge' would be 1/4 the gross volume of the jar). "Undercharging" with material tends to exacerbate media wear, and this case, that's exactly what we're trying to accomplish! Mill until all the sharp corners are smoothed. Further rounding and 'easing' of the corners will occur with time. Thoroughly clean the jar and the media of any abrasive residue before using on your chemicals. Lloyd
Baldor Posted July 23, 2017 Posted July 23, 2017 Thanks. I'm thinking of using a "disposable" paint can for deburring the media, to avoid damaging the good jars.80 grade will be Ok for deburring, or do you think I will need a finer one?
lloyd Posted July 23, 2017 Posted July 23, 2017 Almost any grit coarser than 200-mesh would work, but the coarser the better at the beginning, because that's when you want the fastest wear. Yes, 80mesh, or even 50mesh would be just fine. The grit WILL be milled finer, and the process is self-limiting. Lloyd
Woodchopa Posted August 6, 2017 Posted August 6, 2017 Ok guys sorry if I missed this info somewhere else but here goes, bout a year ago I had lots of people in my ear telling me the danger of milling with my soft lead cast half inch balls, lead dust and smoke and so forth unhealthy. So I found a guy that made me 10 mm pewter milling balls made from lead free top quality pewter mugs and statues etc. They are obviously not as heavy as lead but still have a decent weight to them, they came to me looking to shiny and nice to use haha.I haven't used them yet because I was hoping for some seasoned pro info on pewter milling balls.The seller of these told me I should run a few percent water in the mill jar if milling bp, is that because pewter is harder than lead and it would be safer? should I stick these on the mantle piece for lesson learned and buy hardened lead from overseas? Cheers guys stay safe
OldMarine Posted August 6, 2017 Posted August 6, 2017 Pewter is a non-sparking metal like lead but is more brittle and much lighter. You'll need to mill your powder longer and your media will wear more quickly but it will work.I personally would cast the pewter back into a teapot and buy some lead.There are too many variables in this hobby already without our adding more. Just don't snort your BP or go around sniffing your mill jar and you'll live long and prosper! 1
DavidF Posted August 6, 2017 Posted August 6, 2017 The difference in density between pewter and lead isn't a big issue, as far as powder strength goes. I don't know how brittle pewter is, but with no edges on the spheres, it seems like it might be alright. Brass cylinders certainly do chip off on the edges, but I bet spheres would not. Since the OP already has them, why not try them? I would mill something like baking soda first, to clean the media up. I'd weigh the powder carefully before and after milling. I would discard the baking soda. Then, I'd wash and dry the media. The next test would be to mill just charcoal. Again, I'd weigh it before and after milling. The weight gain- if any- would be my guide as to whether or not I would use it for BP. Charcoal will wear the media way more than BP will. If there is no significant weight gain after milling the charcoal, there will be almost zero after milling black powder. When you know how much wear there will be, you can then wonder if tiny amounts of tin or bismuth could possibly be of concern. Since lead, copper, zinc, and antimony are not known to be problematic, I don't know how much I'd worry about the bismuth and tin. My .02
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