Obsidian????

[tanyafrench]

I have a box of Rainbow Obsidian and I want to tumble it but the pieces are too big for the tumbler. Without a saw is there a way to break this without destroying it. I guess I mean, what will happen if I take a rock hammer and chisel to it? Will it break okay or shatter?

Tanya

[jakesrocks]

Tanya, there's a very good chance that you'll end up with a pile of very sharp chips and splinters. If you do decide to hit them with a hammer, be sure to wear safety goggles and heavy gloves.

[gr]

Tayna, it seems to me that MaryAnn had commented a while back about someone that had come to buy from them had a good way of breaking rock. I think it was obsidian that is what was broken. You might see if she makes a comment to your thread or PM her before you try it. If you do decied to go for it, use a heavy leather glove to hold it and hit it litely at first with increasing force till it gives. And definitle put those safty glasses on! Good luck

[ColtChainmailJewelryDesigns]

I find putting something your going to smash, into a 1gal baggie keeps things from flying around!

[cpdad]

im about to bust some obsidian also...what im going to do may work for you also....works for other stuff also.. ;D...please wear eye protection.

wrap your stuff in old towels...or a croaker sack....and smash away...with a hammer....just be carefull not to smash the stuff to bits.

whack a few times....check sizes...whack some more....of course as you know....you need a little of all sizes for a good tumble....kev.

[tanyafrench]

Thanks all, I do have some safety glasses and I will wear them. I just didn't want to ruin the obsidian. I have wanted to tumble some but most of what I have is just too big. I will try it Kev's way on just a piece or two and see what happens. After all, I do have a MFRB and the pieces aren't too big just too big for the tumblers. If it shatters a piece or two, I will save it until maybe one day I get a saw.

Tanya

[lparker]

I've got no experience making tumble sized pieces from obsidian. I would not smash rainbow. You might think there is an unlimited supply of it. It is hard to get. I believe that if you hit it indiscriminately, you will waste half of it. Add tumbling to that and you get about a quarter of what you started with. I'd hold onto it until I got a saw to handle it. It's too pretty to wreck. I do make stone points from it and I prefer cutting it into slabs before knapping it just to conserve the material.

Lee

[cpdad]

going on what lee said...if what you have is uncommon stuff...forget what i said.

im talking normal stuff....dont go busting extra nice stuff ;D...im still going to bust mine tomm.... ;D....kev.

[rockhound97058]

You need to remember this is glass. Once you smack it with a hammer not only with it break, but will send fractures through the rest of the material. The best way I know of to downsize obsidian is to cut it - but as you said that's not a option so the other best way is using the technique like the knappers use. If your piece has angles to it (non water slicked piece), if you hold one of these angles or faces at a 45 degree angle and using copper or another heavy stone, you can strike it in a downward motion and peel spalls off it. The only draw back to this is the pieces you take off will be thinner and sharp on the edges.

If all fails for you and you need more obsidian let me know LOL - I have several hundred pounds on the ground and soon heading down for another Ton! - My rainbow selection is a bit shy though ;D

[Dr DG]

I have some tumbling size, MOHOGANY OBSIDIAN , and some sheen , I could trade for the rainbow.

[tntmom]

Tanya, do you have a dremel? Get a diamond cutting wheel and it cuts obsidian like butter. I think trying to bust it with a chisel would ruin it. Rainbow is very beautiful, good luck!

Here's the wheel, 1.5" $2.97 each at Widget Supply


~Krystee

[tanyafrench]

I got it from Mary Ann at Stones that Rock so I'm sure it is Rainbow and Krystee, I do have a Dremel and a Dremel Press just like the one you posted. Now I will have to get the 1.5 cutting wheel and I am in business. Mary Ann did not send really large pieces so that should work great. Thanks so much! I've never used the dremel for cutting, only drilling rocks but there is always a first.
Tanya

[stonesthatrock]

I think Krystee has the best suggestion. The man who broke down a 68 lb. piece was for knapping, so it have very shape edges like rockhound said... If any of you want some rainbow we have tons left in all sizes. not too scare here right now... lmao.
mary ann

[gr]

Tayna, did you ever get these going?

[tntmom]

Tanya....

I want to know too!!!!!!

~Krystee

[rocklicker]

I can't stress enough to wear protection when breaking up obsidian. I've had obsidian go through leather work gloves! Pretty stuff but dangerous.
Steve

[tanyafrench]

I sound so weak about this. I did get the cutting blades for the Dremel but so far I have not tried to cut them. I am a bit of a coward. At the show yesterday a friend came in and told me of a man who makes Cabochons fairly close about 40 miles and he said he would introduce me to him. I am going to see if he will cut some slabs for me in exchange of some Rainbow Obsidian. Cowards way out. Anyway thanks for asking. One day I will get a wet saw of my own.

Tanya

[jspencer]

I tried my Dremel last night on some rainbow obsidian. As said it cuts it like butter. I`m glad I read that tip. Dremel produces a lot less waste than a saw blade does. Thier glass etching diamond points are also handy in grinding oout small areas to be smoothed. I have 2 different bits. I have only found one grinding wheel by them that is silicon carbide. (the only grey grinding tips they have) It also works pretty well but etching tips are best I think. Good luck with polishing up what you have cut.

[bobby1]

Yes! Be Careful!
I was reaching into my slab saw to pick up a slab of Obsidian and I found a sharp edge! That was two days ago, but the good news is that it is healing.
Bob

[tanyafrench]

Ouch!! That is some sharp stuff, but I'm glad it's healing.

Tanya