Kevin W Posted February 1, 2013 Share Posted February 1, 2013 Have any of you used a tumbler for polishing copper. What I'm looking for would just put a shine back on copper fresh out of the pickle. Just rinsing my piece in water and wiping it with my shirt a little while gets it mabey 40% where I want it. All my googling results are blast media. Your thoughts on sawdust and pumice? Kitty litter ( clean :) ? Thanks Kevin Quote Link to comment Share on other sites More sharing options...
SmoothBore Posted February 1, 2013 Share Posted February 1, 2013 Walnut Shells are a pretty safe choice for soft materials. . Quote Link to comment Share on other sites More sharing options...
rlbaker Posted February 1, 2013 Share Posted February 1, 2013 We did production investment casting for years and we used all sorts of tumblers for pre-finishing pieces. We didn't cast copper but the same principles should apply. To brighten up the raw castings prior to any real hands on finishing we would clip off the sprues and toss everything into our big steel shot rotary tumblers with shot and a soap solution.The shot comes in pins and cones etc and does a great job of burnishing the interiors of pieces where it is otherwise hard to polish. The best place to check for supplies would be Rio Grande Supply. We also would use vibratory tumblers with abrasive cones but it doesnt sound like thats what you need. Actually I've been out of that business for 20 years now so who knows what sort of advancements they have made. We used to make all of our master patterns,cut all of the molds,did production casting in house, we even made almost all of our tubing,plate and wire. We did this until we finally couldn't compete with imports from other countries, but I digress, a simple steel shot tumbler works great for burnishing soft metal;s like copper. I know I'm dating myself here but we also would strip oxides off of castings prior to tossing them in the tumbler by "bombing" them with a hot solution of cyanide and concentrated hydrogen peroxide. If you did it wrong it would explode and cover you with this nasty solution!! Hard to believe but the cyanide was available off the shelf in a white egg form, looked like white charcoal briquets.Anyway,steel shot is low tech and works great .Bob. Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted February 2, 2013 Share Posted February 2, 2013 How much do you need to do? Do you mind if it gets work hardened from the abrasive? Bits of rubber with polishing compound might be the ticket.... Quote Link to comment Share on other sites More sharing options...
Kevin W Posted February 2, 2013 Author Share Posted February 2, 2013 I was curious about the walnut shells, also corn cob. There are about 900 pcs of dead soft (from welding) #4 copper chain links in 3' + lengths and some water jet cut outs and some I've not used a tumbler before and hadn't even considered it hardening the material. And wouldn't mind it a bit, but, it's hard to imagine these pcs getting work hardened AND NOT getting mangled. Is this hardening/mangling more a result of the medias weight or hardness or is it the tumblers shape? Cyanide! Thanks folks. PS Belongs in copper alloys...check. Quote Link to comment Share on other sites More sharing options...
rlbaker Posted February 2, 2013 Share Posted February 2, 2013 Kevin, part of our product line consisted of cast chain links and normally we would tumble the pieces, rough sand,torch together,take to a higher level of finish depending on item toss back into steel shot tumbler,pull from tumbler,cut buff,ultrasound,polish,ultrasound clean one more time,steam clean,done. Some of the chains were quite heavy some were fine and we never really had any damage issues because the tumbler is spinning at a slow speed and the solution is soapy and foaming so what you really have is a gentle sliding down a slope action on the pieces. Worst case situation we would have to unthread a few tangles. The part of our line that was fabricated chain links from wire,not castings, it was even easier because of the smooth surface of the wire we started with, quite often just torch together chain links ,tumble and give a quick hit on polish wheel and done.That being said you have to make sure you have the right ratio of tumbling media to pieces being tumbled.Our tumblers held a few hundred pounds of shot so we could put a fair number of units in each drum. Even if you use a smaller tumbler it might help cause there is no labor involved other than rinsing out the shot and recharging unit. Load it and walk away and do other stuff. We tested walnut shell charged with polishing compound but it didn't really help for what we were doing. If you are into production work get the largest unit you can afford cause part of the equation is the weigh bear down on the pieces during the slow tumble cycles. Its called "tumbling" but it actually is a slow gentle cascading type slide. I have a brother who is still in the business, I'll ask what the current technology is now. Good luck.Bob. Quote Link to comment Share on other sites More sharing options...
Kevin W Posted February 2, 2013 Author Share Posted February 2, 2013 Well that's just something! Your latter process is just what I'm doing. My # 4 links are going to be attached to the cut outs with a much smaller 10 gauge copper link. The larger links are 3" dia and the 10g are 1". The longest chain all put together is 12'. One of my concerns is the #4 & 10g tumbling together . Rlbaker, what kind of ratio ? if you don't mind. Really something, Thanks Quote Link to comment Share on other sites More sharing options...
Jacques Posted February 2, 2013 Share Posted February 2, 2013 The gun people cleans brass cartridges in tumblers, maybe that will help. http://rocktumbler.com/questions/brass-cartridge-case/ Quote Link to comment Share on other sites More sharing options...
rlbaker Posted February 2, 2013 Share Posted February 2, 2013 Kevin, if you are interested I just sent you contact info.Bob. Quote Link to comment Share on other sites More sharing options...
Kevin W Posted February 5, 2013 Author Share Posted February 5, 2013 Thanks every one, There's the first batch to come out of the walnut media ( lizard litter @ -$1 a pound ) and a short length b-4 the pickle ( PH down, for pools - 93% sodium bi-sulfate ). 2 hrs in the pickle cold and 1 1/2 hrs in the tumbler. I've got a few pcs of that logo section pictured left in the tumbler now to see how the 10 gauge wire holds up. Again, thanks a bunch ! Quote Link to comment Share on other sites More sharing options...
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