rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 20, 2016 12:08:35 GMT -5
Howdy, I'm new on the Board. Thanks for the warm welcome.
Believe it or not, I own a company that makes a high-performance guitar pick that sells for $30.00 -- and we can't keep them in stock.
The product is made from a very expensive thermoplastic called Vespel, which is made by DuPont. With another material we use (totally different), I was able to have a fabrication house tumble these to round the edges of the material, instead of having to sand each one. These came out beautifully, but we haven't tried it yet on the material mentioned above. I'm wanting to experiment to see if I can do this at home.
I have a basic Harbor Freight rotary tumbler, and I am only going to do this test with maybe five (5) picks to see the results.
Here are my questions:
1) What sort of tumbling media might be best for this?
2) Is it possible to make my own compound at home for a test like this? If so, what basic recipe might I use? If not, what compound would you recommend I purchase?
Thank You! Scott
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Aug 20, 2016 12:53:08 GMT -5
We tumble stones. A very different animal.
Industrial tumbling as u describe is usually vibratory and uses ceramics of various categories.
I have zero specific info regarding polymers. But have been in facilities with cubic yard size vibes running polymers.
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dottyt
spending too much on rocks
Member since July 2016
Posts: 305
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Post by dottyt on Aug 20, 2016 13:45:34 GMT -5
Look into the Mohs scale, figure out the hardness of the picks, and tumble as if they were stones of that hardness? (Since it is an experiment just use the tumbler you have.) If they are $30 for you, as opposed to retail, you might want to do something more tried and true since I have ZERO idea if this would work!
Here is a list of gemstones with their hardness and density to see if you can find a stone that matches. If you can then research tumbling that stone. There might be better lists. This one is alphabetical and is for gemstones not industrial material.
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 20, 2016 15:07:51 GMT -5
Thanks to both of you. I realize that is an experiment.
Thanks Again! Scott
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,562
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Post by jamesp on Aug 20, 2016 17:23:56 GMT -5
A small operation near me used to tumble pencil erasers. He extruded his own erasers. I believe the eraser mix had an abrasive. I don't think he added abrasive. Mass tumbled them against themselves with no media. That won't work in this case. You got to have abrasives.
I would get a small vibratory tumbler. Sounds like you are doing small quantities. I would use plastic pellets and aluminum oxide.
Plastic and rubber is used on tumbling barrels and lasts a long time. Guessing it will wear slow. Maybe a search on tumbling plastics would get you closer to target process.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,562
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Post by jamesp on Aug 20, 2016 17:30:17 GMT -5
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Post by Peruano on Aug 20, 2016 17:44:13 GMT -5
Depending on how hard, it might be a dry tumble, and definitely a vibratory machine. Corncobs intended for pet bedding could be the carrier of whatever polish or grit was elected to try.
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 20, 2016 18:35:48 GMT -5
Thanks for the continued advice, and James, thanks for the Kramer link.
If I may ask for clarification:
1) In this instance, why would I want vibratory vs. a round tumbler? 2) I have some walnut shells I bought from Kramer last year. They didn't seem to do any cutting of the edges in a small vibratory machine when running it dry. Is there some sort of compound I could add to the walnut shells (or even soapy water?) to help them cut more?
Thanks so much for giving me a little education on this.
Scott
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 20, 2016 19:26:09 GMT -5
Look into the Mohs scale, figure out the hardness of the picks, and tumble as if they were stones of that hardness? (Since it is an experiment just use the tumbler you have.) If they are $30 for you, as opposed to retail, you might want to do something more tried and true since I have ZERO idea if this would work! Here is a list of gemstones with their hardness and density to see if you can find a stone that matches. If you can then research tumbling that stone. There might be better lists. This one is alphabetical and is for gemstones not industrial material. Dotty, thanks so much. I searched high and low on this. The material is rated E-45-60 on the Rockwell Hardness scale, but I could find no Mohs rating for it. Is there a way to do an approximate conversion on this number from Rockwell to Mohs? Thank You! Scott
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 20, 2016 19:39:23 GMT -5
Folks, someone had warned me that the picks, since they are flat, would stick again the flat spots on the back of the tumbler, and that seems to be what's happening. Would a small vibratory unit prevent this?
Thanks, Scott
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 20, 2016 19:52:16 GMT -5
Folks, someone had warned me that the picks, since they are flat, would stick against the flat spots on the back of the tumbler, and that seems to be what's happening. Would a small vibratory unit prevent this?
Thanks, Scott
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Post by mohs on Aug 20, 2016 20:04:37 GMT -5
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Post by Jugglerguy on Aug 20, 2016 20:08:47 GMT -5
I have a dozen stone picks in a Lot-O vibratory tumbler right now. This is only my third attempt at tumbling them. The others have turned out well. Rotary tumblers round off the edges of stones and make them more rounded. Vibratory tumblers are better at retaining the original shape of a stone. When you tumble flat things like cabochons or guitar picks in a vibe, you need more ceramic media to be sure that the flat sides get polished. I like to use at least 50% ceramics.
I also tumble Petoskey stones in a vibe. They're softer than most stones, and normal methods don't work. I tumbler them in corn cob with aluminum oxide grit and the. polish. I use 500 grit and then polish. When I tumble Petoskeys I use even more corn cob media to rocks, probably more like 70% corn cob. I try to get the stones to float around in the corn cob without touching each other much.
I have no idea how you should tumble your plastic picks, but that's my experience with rocks.
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Post by Peruano on Aug 21, 2016 8:11:00 GMT -5
Yes flat stuff will somewhat cling together, and thus you need small not flats to separate them frequently as they move. Vibes don't change the shape of things as much as rotaries, and are faster. I know soft stones that bruise easily can be tumbled in dry media like corn cobs. I'd guess Jugglerguy's advice above is a good start. I'd guess that ceramics might not work for your picks. In general words, I've always felt that the media that I use to 1. cushion the load; and 2. provide detail to get into spaces or keep flats apart, should be softer than the material being processed. If your picks are softer than the ceramics, you will have scratched picks. It certainly works that way when I process stones of two distinct hardnesses together. The hard ones polish and the softer ones stay a satin finish (i.e. are scratched by the harder ones). Make sense?
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 21, 2016 12:24:13 GMT -5
Peruano, thanks so much for responding.
Actually, I WANT the picks to be scratched on the flat surface (will explain in a second). I only need to round the edges, that's all. One of my fabricators has done this for me before, and I may go back to him to save time. However, I think he may have used a centrifugal disc machine.
The reason I don't need to polish the sides is our picks are so advanced and above the average that we are merely sanding down the sides with a 600 grit sandpaper and they're totally cool with that.
So, it's fine if the plastic is softer than the media. I'd actually prefer the HARDEST media I can find to cut this stuff, even if it dents the flat sides slightly, since I'll just sand that off. Any suggestions? I'm wondering about tumbling dry too.
thank you! scott
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Aug 21, 2016 12:45:58 GMT -5
Any suggestions? I'm wondering about tumbling dry too. thank you! scott Yes. Get to experimenting and report your results here! Get ceramic media with various grits to see what finishes as you desire. Vibratory tumbler has more desirable faster action overall. Action adjustable. In the huge vibes I witnessed they had perhaps 20-30% product and the balance ceramic media. Never saw an industrial rotary, all are vibes...
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 21, 2016 13:01:28 GMT -5
Can someone please send me instructions on how to set notifications? Right now I am not being notify via email when someone posts something new. This interface is different than any I've used before.
Thanks!
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Post by Jugglerguy on Aug 21, 2016 16:32:46 GMT -5
Here's a picture of my rock to guitar pick to ceramic ratio of the batch I just took out. It's hard to tell from the picture, but there's more ceramic in the load than anything else. My picks were shaped on grinding wheels and then tumbled. I just knocked the edges off all the way around and then tapered the business end to be thinner. I have zero experience playing guitar, but this is what my neighbor and the guy who runs the guitar shop both told me to do.
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 91
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Post by rockrockrock on Aug 22, 2016 0:06:22 GMT -5
Shotgunner, I will indeed report back. Gonna try running them dry with ceramic media in the round tumbler, then if that doesn't work go buy a small vibratory unit from Harbor Frieght. Thanks for taking time to post in this thread. Wow, Juggler, thanks for taking the time to take and post the picture. This is very helpful to me. May I ask: When tumbling with this media, were you tumbler dry, and if not do you also use some kind of compound with it, or just soapy water, or ....? Thanks! Not trying to sell you anything, but here's what our stuff looks like: www.charmedlifepicks.com/Thanks Again, Scott
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Post by Jugglerguy on Aug 22, 2016 7:40:03 GMT -5
I fill the barrel with rocks and ceramic, then fill it with water. Then I cover the opening with my hand and drain out all the water. While it's running, I add 1 tablespoon of borax (this is in a 4.5 lb tumbler). Then I add 1/2 teaspoon of 500 grit aluminum oxide. I run it for two days. Then I thoroughly rinse and repeat the exact same thing in a dedicated polish barrel using aluminum oxide polish from The Rock Shed.
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