Rock polishing methods?

[OwenT]

I'm starting to accumulate some rocks and I want them polished. I have used silcarbide sandpaper to polish some small crystals but it's difficult to use on larger, odd-shaped things. I have some petrified wood chunks and some other odd river rock that I want to polish. I was wondering about micro mesh. I saw someone use it on epoxy and it seems like it might be easier than the regular sandpaper. What other options are there for polishing odd shaped stuff, any power tool mounted options?

 

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[willjo]

I polish mine in a rock tumbler and my petrified wood comes out fantastic.

 

[Eu_citzen]

Well, basically there are 4 methods of polishing rock.

1. Carving, using power tools, like a dremel.
2. Cabochon cutting, using a cabbing machine. Similar to the machines you use for sharpening metals (bench grinders).
3. Faceting, using a faceting machine.
4. Tumbling, using a tumbler.

 

[OwenT]

When tumbling, how much of the shape is preserved? I'd like the wood to still look like a piece of wood, not just a round shape.

 

[willjo]

Polished pet wood

It stays the same shape but polished. This is palm wood and some polish up better than other pieces.

 

[willjo]

Two more pieces

Two more pieces not palm wood.

 

[OwenT]

Looks nice, I just don't like how the corners get so rounded.

 

[galenrog]

There are two types of tumblers. Rotary or drum tumblers are what most are familiar with. The other type is a vibratory tumbler. A trip to your local rock shop or lapidary club will give you far more information than I can, since you would be able to look at the equipment while being given an explanation.

Time for coffee.

 

[Eu_citzen]

Basically that's what tumblers do. They round off stuff, to polish it. Rotary more so then vibratory.
With a cabochon machine you can do what your looking for. BUT it's an expensive piece of equipment.
Is there a local lapidary club?

 

[hvacker]

My wife likes to do free form on a cab machine but will also do more traditional shapes to place in a bezel. I slab the stones for her and she also buys some she likes.
I like free form as it seems to respect the stone. I do some similar things with wood.
She bought a six wheel cab machine used on Ebay but it wasn't cheap.

The Natural History Museum here has a rock club with a bunch of really nice machines and lessons for making cabs and jewelry. If there is something like that where you live it's worth looking into. I know most would like to work at home on their own equipment but for starting out you might want to find alternative options. I know learning from someone that knows saves a bunch of mistakes.
BTW it's very rewarding. Even though I only do slabs it's still exciting doing a cut.

 

[OwenT]

I think I will try to get to a club shop some day then. I think there are some a little over an hour away.

 

[Eu_citzen]

I think I will try to get to a club shop some day then. I think there are some a little over an hour away.

I'd say try it at the club, if you like it then you can invest in a cabbing machine to skip the drive to the club.