Petrified wood: should I tumble these?

[doublebluff]

I have a couple pieces of petrified wood that I would like to clean up. The top one especially. I include pics of them both wet and dry.

I have an AR-1 tumbler. I know they won't tumble in the classical sense, but will they... roll?  Also, in the middle picture... the yellowish material on the right of the top stone, do you folks think these are part of the wood or is it waste that accumulated there?

[brybry]

If you want to retain the texture look, tumble it with stage 2 grit for a week or two to clean off the outside. Go with stage 3 for a week or two then move to the other steps.

[rocknrob]

Boy, I'm not sure you're going to get enough friction happening to get a good polish on those even if you can fit it in the barrel. You probably are going to need a bunch of smaller rocks and possibly ceramic media to get it to start.

[Bob]

I do pieces like this lots. There is thick rind over 1/8" thick which will takes a couple of months in rough grind if you want really nice results.

[HankRocks]

The petrified wood will tumble and will take a polish as I have tumbled pieces that large before. I run them in a Thumler's Model B which is a larger barrel than your AR-1, here a couple of examples;

This piece of Palm Wood is about 1 1/2 pounds. It was not tumbled smooth as the white colored areas are mostly depressions.

IMG_6013 by Findrocks, on Flickr

Another piece about the same weight, first pic is after 3 or 4 coarse stage runs;

IMG_3374 by Findrocks, on Flickr

Same rock polished;

IMG_3388 by Findrocks, on Flickr

Petrified Wood can often have soft zones that will not polish. In some cases the contrasting color of the softer zone can hide the fact that it's unpolished except to very close inspection. As with the Palm Wood piece above it adds to the character and also hides the fact that the surface is not smooth.

[doublebluff]

Great thoughts, all. Thanks. Nice pics as well! I think I will dive in. I will post how it goes.

You are also making me think about getting a bigger tumbler!

[HankRocks]

May 26, 2024 7:41:46 GMT -5 doublebluff said:

Great thoughts, all. Thanks. Nice pics as well! I think I will dive in. I will post how it goes.

You are also making me think about getting a bigger tumbler!

One thing I forgot to add, there is Petrified Wood that is soft thru out and will not really be worth the time trying to polish. Learning to distinguish those pieces is a good part of the learning process. If I had the pieces you pictured in my hand I could tell which to tumble and which are yard rocks. I would say the last two could be tumbled.

Oh and look for fractures that could cause the big piece to separate into smaller pieces during the tumbling process.

and... You decide when a rock is ready to move to the next stage. Leaving some of the roughness on a piece can, IMHO, can add a bit of character to the piece.

A larger tumbler barrel will help with the bigger pieces as there will be more grinding as long as you have a good balanced size mix in the barrel.

Good luck.
Henry