jbrian
off to a rocking start
Member since November 2014
Posts: 11
|
Post by jbrian on Nov 19, 2014 22:31:01 GMT -5
Hello everybody I'm new to the forum and have found this to be a great resource.
Anyways I have been tumbling rocks with my daughter for about a month or two and we just recently bought a vibratory tumbler.
We are trying to polish some calcite and some limestone which we found while hiking.
My question is... Will my ceramic shapes be too hard for the calcite and limestone which both have a hardness of about three on the Mohs scale?
Thank you for any information!
John
|
|
jbrian
off to a rocking start
Member since November 2014
Posts: 11
|
Post by jbrian on Nov 19, 2014 22:37:29 GMT -5
Also we have some lapis that we are trying to polish which has a hardness on the Mohs scale of 5 to 6. Is that too hard to polish with the limestone and calcite which are hardness of 3?
|
|
|
Post by Jugglerguy on Nov 20, 2014 7:02:15 GMT -5
I don't think you'll be able to polish limestone or calcite in a tumbler of any kind. My experience with limestone is with Petoskey stone. I've never heard of anyone successfully tumbling it. It tumbles very quickly in the first stage in a rotary tumbler, but then I finish it with a flat lap grinder. I've heard of people hand sanding it to a finish too.
It's suggested that beginner tumblers should start with agate or jasper to start with. It takes a long time, but takes a great shine.
I have no idea about lapis.
|
|
|
Post by fantastic5 on Nov 20, 2014 8:36:00 GMT -5
Welcome to the board jbrian! I am new-ish to tumbling myself, but I am sure the more experienced amoungst us will lend a hand. One thing I did learn the hard way is to start with some good hard agate or jasper for your first tumbles. The softer materials are difficult to manage and downright impossible for a beginner (personal experience).
|
|
tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
|
Post by tkvancil on Nov 20, 2014 11:19:26 GMT -5
Can't speak to the calcite or limestone, haven't ever done those. With a hardness of 3 they are going to be a challenge to get a shine on. Haven't done lapis but have done things with a similar hardness. So I can say that the ceramics work with things in that 5 to 6 hardness range.
We have one skilled tumbler on the board who uses a Lot-O vibe. He has mixed obsidian and agate with ceramic and gotten excellent results on all the material. In theory that is not supposed to work but it did.
|
|
jbrian
off to a rocking start
Member since November 2014
Posts: 11
|
Post by jbrian on Nov 20, 2014 11:53:59 GMT -5
thank you guys! Yesterday I took out all the ceramic and just had the soft rocks with plastic pellets and pre-polish. They have been in the vibratory tumbler for about 24 hours and nothing good is happening...lol
I will definitely go with some agates and jaspers so we can have some success. I don't want my eight-year-old to lose her interest.
|
|
tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
|
Post by tkvancil on Nov 20, 2014 13:11:31 GMT -5
Sounds like your on the right track. Best of luck.
For future reference plastic pellets and a vibe don't usually work well together. Plastic for rotary ceramic for vibe.
|
|
jbrian
off to a rocking start
Member since November 2014
Posts: 11
|
Post by jbrian on Nov 20, 2014 17:50:06 GMT -5
oh man, another nice bit of info! thanks ken.
|
|
|
Post by iant on Nov 21, 2014 2:27:36 GMT -5
Try to only use the same hardness of rocks in a batch, otherwise your softest rock will wear away quicker than others and never take a shine. Lapis is difficult to deal with as it is made up of a number of different minerals with different hardnesses. So you sometimes get pits where the softer material has worn. Sorry if it's not what you want to hear.
I made the mistake of putting some Skye marble in with my agates, just to make up the batch, and the marble wore away to practically nothing in the process!
|
|
|
Post by connrock on Nov 21, 2014 9:15:36 GMT -5
As has been mentioned,,,tumbling rocks with a different hardness isn't a good idea and seldom works. I don't really know how to explain it but Moh's scale can be a little confusing. For example,,,,corundum (ruby and sapphire) is a 9 on the scale and diamond is 10 yet diamond is 10 times harder the corundum!
I don't know what the real "hardness" is between calcite and limestone but both are very soft for successful tumbling,especially for a beginner. I think some of the best advice you've got so far is to stick to agate and jasper right now. Starting out with a good quality tumbling rough is a must and as the saying goes,,,junk in,,,junk out. I would start with a good quality agate or jasper but I wouldn't mix them in a load. I would buy 1 type of agate or jasper and do it alone for starters.Make sure you buy enough so that you have some to add after some of your rocks are roughed enough and you have to take them out,,, while the rest of the rocks get roughed in enough to go to the next stage.
The rough stage is the most important stage of the entire process,,,if you want perfectly shaped,highly polished rocks.It may take months to do this but it is what it is and that's that!
ALWAYS remember that at LEAST 1/3 of the load HAS to be very small rocks in the rough stage and ceramic media can be used in the following stages. Good luck,,,, connrock
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Nov 21, 2014 9:26:49 GMT -5
Using glass for media connrock in the vibe with the Mohs 7 coral. Coral shiny, glass not. But, the glass shinier than in the rotary. And the instructions for the Viking said you could mix various hardnesses. I don't think so, but time may polish the glass too, will see.
jbrian: the hardest material in the tumbler seems to steal the polish. Never had it go the other way. But it is good to put a couple of softer test rocks in every load to see how it reacts. No harm. I would not put a couple of harder rocks in with a load of softer rocks though, may dull the whole load.
|
|
jbrian
off to a rocking start
Member since November 2014
Posts: 11
|
Post by jbrian on Nov 22, 2014 10:52:00 GMT -5
thanks guys. My daughter and I went on eBay and found some pretty green aventurine to try. This way they're all from the same batch and should all be the same hardness and everything. One website said it's a good stone for beginners but then right after I bought it ( like 10 seconds after I hit 'buy') my daughter read from a different website that it can be difficult to polish because of the mica inclusions. Too late now- I guess I will find out. I'll try to post pictures if we have success!
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Nov 22, 2014 11:06:59 GMT -5
Agates are about the easiest. You can run the adventuring in rough grind and round it with no problems. You may want to run it with plastic pellets in the last two stages(probably 500 and polish). It can frost like rose quartz or amethyst, but it is easy to tumble. No matter, you will get an education, but it will do fine if you avoid frosting it. Here is rose quartz that has some frosting. It was run with a load of 'tougher' agate as a test rock to see how violent the tumbler was treating the agates. The agates were fine, but the 'frost sensitive' rose quartz had visible damage. I intentionally wanted the tougher agates to tumble hard/violent enough to slightly damage the rose quartz to wear the agates faster. The harshness of the tumble was adjusted by running the barrel less full, say just less than 2/3 full. i would run the adventurine a bit over 3/4 full barrel. The fuller the gentler the action. And as mentioned,plastic pellets in the last 2 stages. A link to the agatized coral that was run with the rose quartz www.flickr.com/photos/67205364@N06/sets/72157640716464923A photo of the abused rose quartz :
|
|
jbrian
off to a rocking start
Member since November 2014
Posts: 11
|
Post by jbrian on Nov 25, 2014 20:38:47 GMT -5
Thanks James. I'm going to try some aventurine with some agates. I'll watch out for frosting on the aventurine and take them out of it happens.
|
|