Vibratory tumbler denting 6061 T6??

[woodchucker]

I'm not sure what is going on here. When I put these in, they were not dented, or blackened.
Originally started with large ceramic triangles, then after went to the plastic to see if I could get into the lightening areas.. Unhappy I switched to the ceramic balls. I am not sure why everything is dented and blackened to the point I can't scotch brite it off. Normally I can get rid of the black, just oxidation..
BUT really unsure why it dented.

 

[Jake M]

I'm NOT pretending to be an expert here, my experience is with a drum style rotary tumbler and a vibratory one with more of a square basket, where the media "rolled" around a horizontal axis, not like what I think is a more standard style such as you have. But my first thought, looking at the tumbler, the dents, the shape of the parts, the size of the parts (scaled what I can from the photo), my first thought (for whatever that's worth) is that the dents are from the parts contacting each other, not so much the media. And less likely (nothing I've ever used that a center rod/post through it), "maybe".... It's possible that the parts got laid up against that post for some period of time?

I'd try a round with just one in there to see if it cleaned up, or did the same thing.

 

[woodchucker]

I'm NOT pretending to be an expert here, my experience is with a drum style rotary tumbler and a vibratory one with more of a square basket, where the media "rolled" around a horizontal axis, not like what I think is a more standard style such as you have. But my first thought, looking at the tumbler, the dents, the shape of the parts, the size of the parts (scaled what I can from the photo), my first thought (for whatever that's worth) is that the dents are from the parts contacting each other, not so much the media. And less likely (nothing I've ever used that a center rod/post through it), "maybe".... It's possible that the parts got laid up against that post for some period of time?

I'd try a round with just one in there to see if it cleaned up, or did the same thing.

Great point about hitting each other. I hadn't thought of that. Everything I have done in the past was smaller, and with less mass less likely to do damage to each other. Thanks for hitting me on the side of the head, I missed the forest for the trees.

 

[GeneT45]

Happened to me several years ago and I chalked it up to parts banging against each other. My tumbler (Thumler's) bowl is molded up around the center post, so it definitely wasn't that. I've pretty much given up on tumbling for finish / deburring - it just never does quite what I want.

GsT

 

[ChazzC]

Great point about hitting each other. I hadn't thought of that. Everything I have done in the past was smaller, and with less mass less likely to do damage to each other. Thanks for hitting me on the side of the head, I missed the forest for the trees.

Makes sense: I don't have a tumbler, but those that I have seen in action have a lot of media volume vs. part size. Almost hypnotic watching the parts move around in the media.

 

[woodchucker]

Happened to me several years ago and I chalked it up to parts banging against each other. My tumbler (Thumler's) bowl is molded up around the center post, so it definitely wasn't that. I've pretty much given up on tumbling for finish / deburring - it just never does quite what I want.

GsT

I modified my tumbler. This is my largest pieces. I needed to get some edges that I was too lazy to debur softened up and some flat faces inside the bottom of the weight relief. It didn't work. But no big deal, it's in use.

 

[Flyinfool]

Those parts are also pretty big for that little tumbler. I have the same tumbler that I use for cleaning brass before bullet reloading, even my 7mm rem mag cases are a bit big for that tumbler. I wonder if there is even enough room for the parts to actually tumble in there. I can see where areas of the parts would rise well out of the media and then fall back down possibly hitting the other part or even leaning against the center post and/or wing nut.

 

[Nesse1]

I've used a similar tumbler to polish golf club heads. These heads are either stainless steel or a nickel alloy, though, so much harder than aluminum. I use coarse ceramic media, wet. The parts in question look to need more time in the machine. I usually allow about 30 minutes machine time for the work I do.

 

[Flyinfool]

I had another thought.
The amounts of media shown back in the first post is no where near enough media for vibratory tumbling. I do not know if that is how much you used or if that was just as a sample to show the types used. The tumbler should be near full when loaded whether there is just one part or 100 parts in there. I usually use ground walnut shells in mine as they work great on dirty brass and bring it to a near polish, AL is also soft and the walnut might also work good for that. I have never tumbled AL. I have also never tumbled with liquid in there.

 

[woodchucker]

The ceramic balls require liquid. Just water and dish soap.
I find if I put too much in, I don't get enough action, so it's trial and error to find the correct fill.

I also have walnut, did not use it for this.