thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on Mar 31, 2008 16:11:52 GMT -5
I just got some black tourmaline, and would like to tumble it. I've made some pre-forms too, but it cuts like glass! Have any of you tumbled black tourmaline before?
Thom
|
|
geogoddess
spending too much on rocks
Member since December 2007
Posts: 287
|
Post by geogoddess on Mar 31, 2008 20:57:35 GMT -5
I have...unsuccessfully.... its wayyyyyy too soft (even though it has a hardness of 6). It wore away very quickly, and while it has a half decent shine... it doesn't have any of the nice properties of tourmaline. This was in a rotary tumbler.
It might work in a vibe tumbler, under very close inspection....but I haven't tried that.
|
|
|
|
Post by Bikerrandy on Mar 31, 2008 21:34:44 GMT -5
You might try skipping the coarse grind and start with the 120/220, then check after a day or two.
|
|
thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on Apr 1, 2008 5:54:15 GMT -5
Thanks! I have a Raytech vibe. My book says Tourmaline is 7.5 on the hardness scale... I wonder why it tumbles so soft? It cut like glass... so SOMETHING seems odd about that! I have cut one preform cab, but fromt he way it cut, and from what you guys have said, it probably won't do well. That's a shame. I might just skip it and do some agate I bought Saturday! I KNOW it tumbles well!
Thanks for your help!
Thom Tapp
|
|
|
|
Post by Bikerrandy on Apr 1, 2008 6:35:40 GMT -5
Hmmm, what grit are you running with your vibe? In a vibe, 120/220 is the coarse stage. Maybe you should tryt starting out with 500.
|
|
thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on Apr 1, 2008 7:01:03 GMT -5
I haven't started it yet. I use 220 for my first grit, 600 for my second and then polish. Also, should I use ceramic or plastic pellets?
Thom
|
|
geogoddess
spending too much on rocks
Member since December 2007
Posts: 287
|
Post by geogoddess on Apr 1, 2008 7:41:20 GMT -5
Ok... its been a bit since my mineralogy class... most tourmalines vary between 7 and 7-5. I thought I read 6 somewhere, recently, but I can't find that book.
The way that it cuts, has alot to do with its crystal structure. For the similar reasons as to why agates are "tougher" than amethyst, even though they are the same hardness (and essentially the same material).
I've seen some nicely polished tourmaline, so if you do try it, good luck!
|
|
thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on Apr 1, 2008 8:03:51 GMT -5
Thanks! I'll give it a try. I appreciate your input!
Do you think I should use plastic pellets?
Thom Tapp
|
|
SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
|
Post by SirRoxalot on Apr 1, 2008 9:11:24 GMT -5
Some tourmaline will, I believe, tumble nicely. One occasionally sees tiny to small polished bits of pink and green. Whether these are in fact tumbled or polished by hand is the question. The other question is whether the elbaite variety is a bit tougher than the schorl variety; I suspect it's a lot tougher given it's popularity as a gem.
I'd say if you can get your black tourmaline to take a polish on the cabbing machine, might as well try it in the tumbler, at least if it's not nice xls or good for anything else. If it's crumbly though, don't bother.
Use lots of pellets, fill the barrel fuller than usual, don't let them drop down too hard or they'll fracture up, low speed if possible would be helpful as well. Using small material to make up about a third of the load is probably a good idea as well.
Give it a whirl, but don't expect too much, it's probably going to be a challenge!
SirRoxalot
|
|
geogoddess
spending too much on rocks
Member since December 2007
Posts: 287
|
Post by geogoddess on Apr 1, 2008 18:02:49 GMT -5
The stuff I bought was *Definitely* crumbly. Majorly so. Was not happy with the tumbler experience on it.
|
|
grayfingers
Cave Dweller 
Member since November 2007
Posts: 4,575 
|
Post by grayfingers on Apr 2, 2008 19:10:47 GMT -5
|
|
thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on Apr 5, 2008 9:12:03 GMT -5
I have a batch of black tourmaline in the vibe now. After one night, several of the preforms show "cat's eye!" The fellow I bought it from told me he thought some of it was, but this is great! The cabs seem to be doing well so far in the 220 grit, but I still don't know how they will polish! I'll post samples when they get "out of the oven!"
Thanks everyone for the tips!
Thom Tapp
|
|
Nov 14, 2024 18:17:57 GMT -5
*
Nov 14, 2024 18:17:57 GMT -5
*
Nov 15, 2024 17:44:51 GMT -5
Nov 15, 2024 17:44:51 GMT -5
