NightHawkInLight Posted March 11, 2008 Share Posted March 11, 2008 So I have just this last month been using a new mill. With my equipment upgrade I have also upgraded to 50cal lead ball media. The lead is significantly harder to clean than the smooth nickel plated surface of the quarters used in my old mill, so after milling up ammonium perchlorate cleaning has turned into a bit of an issue. After rinsing, soaking and rinsing again over about a half hours time once the media dried it still had a white film over it. This could all be from my softener salt, but I don't want to go and start milling a fresh load of BP with AmPerc contamination. Multiple reasons for that. I believe my media is clean as it is now because at the same time as rinsing off the perc I also rinsed some media used to grind charcoal and there are no traces of that left. Regardless, for future use, what cleaning steps should typically be used when changing oxidizers in your mill? Link to comment Share on other sites More sharing options...
jacob Posted March 11, 2008 Share Posted March 11, 2008 Well, the best way to avoid cross-contamination would be to have separate media for each chemical you want to mill, if you have a source for cheap Lead that should be easy, this is what I plan to do when I get my new jars up and running. But besides that, did you try hot water? or a detergent of somekind?I don't know the solubility of AP but I think that would help. Link to comment Share on other sites More sharing options...
NightHawkInLight Posted March 11, 2008 Author Share Posted March 11, 2008 Unfortunately lead is fairly expensive for me. About $15 for 100 lead balls (i know, it's a ripoff) It takes 200 for my mill. Maybe when I get some more cash in the summer I'll buy more. I did use hot water and a little bit of dish soap. I believe all the AmP is off, but I was wondering if there was a specific way that is best. Link to comment Share on other sites More sharing options...
Mumbles Posted March 11, 2008 Share Posted March 11, 2008 Ammonium perchlorate in general is one of those chemicals I would keep separate media for. However, I am sure they are clean. Ball milling with something else will help to get it off. Chose your cheapest chem, usually KNO3. Ammonium perchlorate isn't really a "dangerous" contrminate. It will render your comp useless, not more dangerous, well unless you're milling chlorate, which really is something that necessitates separate media. Ammonium perchlorate is pretty soluble as it is, so you probably got most of it. The white stuff is likely just lead oxide or something from the drying process, or from softened water like you said. Might want to dry mill the media a bit, and run them over a screen quick to knock of any loose debris. Link to comment Share on other sites More sharing options...
NightHawkInLight Posted March 11, 2008 Author Share Posted March 11, 2008 I've heard from a couple people that ammonium perch is one of the oxidizers you never want to mill with any fuel. Is that untrue? Would I be safe to mill ammonium perc with charcoal or the like next time? I was more afraid of a mill explosion with AmP contaminated BP rather than composition sensitivity afterwards or kno3 conversion to ammonium nitrate. Link to comment Share on other sites More sharing options...
FrankRizzo Posted March 11, 2008 Share Posted March 11, 2008 It's not safe to mill any oxidizer with any fuel, the exception being BP mixes. That white coating you see on the outside of your media is likely just an oxide coating on the lead, not residual AP contamination. You really should have separate media for fuels, oxidizers, and BP. A good way to clean the media and the jar is: fill the jar with media, put in a drop of dishsoap, then fill with warm water to just over the height of the media. Put it on your mill and let it run for ~10mins., then rinse off the soapy water with plenty of clean water. Link to comment Share on other sites More sharing options...
NightHawkInLight Posted March 12, 2008 Author Share Posted March 12, 2008 Thanks for the cleaning tip. I do plan on different media eventually, but my cash is low right now in the winter months. Cleaning is an inconvenience I'll have to live with for now. Link to comment Share on other sites More sharing options...
TheSidewinder Posted March 12, 2008 Share Posted March 12, 2008 It should be pointed out (given this is the Safety Forum) that the "exception" for BP doesn't excuse you from milling far away from anything that could get damaged if the mill blows, and following all the other normal safety precautions. Milling BP is much less dangerous than other comps, but there's stil some danger. Stay safe. Link to comment Share on other sites More sharing options...
Bonny Posted March 12, 2008 Share Posted March 12, 2008 I use brass media and clean regularly. I really only mill BP mixes and once in awhile a straight nitrate. My main concern would be trace amounts of sulfur that soap and water may not remove, if at some point I use chlorates.What would be the best way to ensure there is no residual sulfur left on the media? An acid bath maybe? Link to comment Share on other sites More sharing options...
Mumbles Posted March 12, 2008 Share Posted March 12, 2008 I would absolutely get new media for chlorate. Besides residual sulfur on the media, the brass will also react with the sulfur to make copper sulfide. You may notice your media tarnishing after a while to a blackish or greyer color. I absolutely would not mill chlorate with media that has been being used for BP or sulfur. Link to comment Share on other sites More sharing options...
Bonny Posted March 12, 2008 Share Posted March 12, 2008 I would absolutely get new media for chlorate. Besides residual sulfur on the media, the brass will also react with the sulfur to make copper sulfide. You may notice your media tarnishing after a while to a blackish or greyer color. I absolutely would not mill chlorate with media that has been being used for BP or sulfur. I have noticed some tarnishing on some pcs of the brass, black-blue colour. I'll definately get a new set of milling media before doing anything with chlorates. Link to comment Share on other sites More sharing options...
justanotherpyro Posted March 12, 2008 Share Posted March 12, 2008 A good way to clean the media and the jar is: fill the jar with media, put in a drop of dishsoap, then fill with warm water to just over the height of the media. Put it on your mill and let it run for ~10mins., then rinse off the soapy water with plenty of clean water. This is what I usually do as well. I crank the RPM's on the mill up to about double or triple that of normal operation. If there is some serious crud in there you can use something abrasive like a small amount of sand in the water but I don't really recommend it. Link to comment Share on other sites More sharing options...
TheSidewinder Posted March 13, 2008 Share Posted March 13, 2008 Yes, bonny, that's what you're seeing. I have Brass media too, and it's stained as described. I won't ever use them with Chlorate. I still have a few feet of my rod stock left. When I get inspired, I can cut it up. I should get enough for use in ONE tub off my Lortone, at least. Link to comment Share on other sites More sharing options...
Swede Posted July 8, 2008 Share Posted July 8, 2008 This is an old thread, but I tried something last night with my brass media that worked spectacularly well. When I bought my ball mill, it came with abrasives to fulfill its design feature of being a rock tumbler. With my brass black and stained with sulfur compounds (I believe it is sulfur that stains it badly), I loaded a jar with all my brass media, added 3 tablespoons of 500 grit (pre-polish) abrasive, and let it turn for two hours. The brass was as clean as a whistle, and no doubt the abrasives took off a few thousandths inch (0.05mm) of brass, so contamination was physically removed. If you are concerned about contamination, try some 500 or 600 grit tumbling abrasive in H20. Works great. Link to comment Share on other sites More sharing options...
Sylar Posted July 8, 2008 Share Posted July 8, 2008 I always found charchoal or coarse dry sand pretty effective in cleaning my media (soft iron round stock, for the time being) The charchoal leaves a thin dust layer that keeps everything free flowing and protects the iron against rust to some degree. Obviously, cleaning with water is a nono with iron media. Rust forms faster then you can dry the remaining water. I plan to upgrade my media to lead filled copper pipe or brass round stock sometime in the future. And make a perchlorate cell. And a fuse machine. And a star roller. And a babington style burner to make MgAl alloy. And a device that makes extra time and money for pyro ... Link to comment Share on other sites More sharing options...
TYRONEEZEKIEL Posted October 4, 2008 Share Posted October 4, 2008 Milling Ammonium Perchlorate? Ive heard from quite a few rocket guys that when small enough, it will fuel-air explode! Link to comment Share on other sites More sharing options...
tentacles Posted October 4, 2008 Share Posted October 4, 2008 (edited) How can an oxidizer have a fuel-air reaction? It doesn't work that way. To have a fuel-air reaction, you need a fuel. Edited October 4, 2008 by tentacles Link to comment Share on other sites More sharing options...
TYRONEEZEKIEL Posted October 5, 2008 Share Posted October 5, 2008 Maybe it becomes pyrophoric or something, I knew a guy who blew up his ball mill doing milling AP. Link to comment Share on other sites More sharing options...
tentacles Posted October 5, 2008 Share Posted October 5, 2008 Tyrone: You're not understanding the situation here. AP is an oxidizer. It cannot burn. When it decomposes, it releases oxygen, which causes things nearby to burn. Making it finer only increases the potential speed at which it can decompose. Now, if the AP reacted with the milling media, or residue inside that jar, that's another matter entirely. Mill AP as fine as you want, even if you milled it down so fine that the particles were individual molecules, it still would not burn - as in, uptake oxygen from air. It's already far more oxidized than atmosphere can achieve, thanks to the miracle of electrolysis. You need to learn, right now, the difference between a fuel, and an oxidizer, if you're going to be a pyro hobbyist. Link to comment Share on other sites More sharing options...
optimus Posted October 5, 2008 Share Posted October 5, 2008 Isn't it also technically an explosive? http://cameochemicals.noaa.gov/chemical/10471 I'm sure I've read accident reports where built-up AP on equipment has exploded due to high impact... Mabye if the jar/media was contaminated? Just throwin' some ideas out there Link to comment Share on other sites More sharing options...
Miech Posted October 5, 2008 Share Posted October 5, 2008 It's considered a very insensitive explosive, and under normal circumstances there is no reason to be worried. Of course, take care in avoiding incompabilities, and you can safely use it. Link to comment Share on other sites More sharing options...
TYRONEEZEKIEL Posted December 11, 2008 Share Posted December 11, 2008 Sorry about the confusion, I was curious, and wanted to be safe than sorry.I know the difference between fuels and oxidizers. I am very involved in high power rocketry, and making APCP. I have just heard a story recently about the incident. I probably did not get all of the details of what had happened. Poor chap most likely did forget to clean his media and mill out first. Also, I know sand to be an excellent way to clean media, as said previously, it will literally remove the residual composition from the media. Link to comment Share on other sites More sharing options...
tentacles Posted December 11, 2008 Share Posted December 11, 2008 Sand is possibly not the best way to clean media - after the media and jar are clean of the chemicals, what will you use to clean off the sand? The sand dust as a small % contaminant is probably quite a lot more dangerous as a friction/impact sensitizer than a microscopic % of ammonium perc. I would recommend charcoal, or KNO3, depending on what you want to mill next, fuel or oxidizer. Link to comment Share on other sites More sharing options...
Bonny Posted December 11, 2008 Share Posted December 11, 2008 You can also use bentonite/kitty litter to clean the media. Mill a batch, throw away the kitty litter and then wash the media with water. Link to comment Share on other sites More sharing options...
FrankRizzo Posted December 11, 2008 Share Posted December 11, 2008 I've used sawdust as well. Link to comment Share on other sites More sharing options...
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