Help! How do I tumble?

Greetings,

With regards to your questions:

1. Will this grit work on your rocks? Sure, it will grind them.  Silicon Carbide Cuts, and Aluminum Oxide smooths.
2. Can you tumble Noiyo Cobble Rocks?  Yes.  Would I recommend it for beginners or for a classroom?  No.   Sure, you can probably smooth them down, and they might look nice wet, but, from what I see online they are unlikely to hold a polish from a rotary tumbler.  And I'm also not sure what your kit is using for Polish, but, I would assume that since Dan&Darci are hiding their grit specs.-that they are probably not good.  You can buy good aluminum oxide polish from The Rock Shed online, all grits prior to polish do not have to be fantastic.
3.  Stage 1: Coarse takes as long as you want until you have the shaped the stone to your liking. Timetables are just an estimate, *you* will decide when to move the stones on to the next stage.
Duration often depends on the mohs hardness of the material (harder=longer) with most agates and jasper taking several weeks and sometimes months in coarse grind.

The Rock Shed online is a good place to buy grit and crushed stones in small quantities.
RoughStone Rock LLC online is a good to place to buy stones cheap, but, you may have to break them yourself into small enough pieces for tumbling (which is work).

I would recommend regular Quartz/Smoky Quartz/Rose Quartz for a classroom.  I consider these to be pretty easy to tumble/polish together in small barrels and observe the progress each week as you go...   Agates and Jaspers will give you better results in the long run, but, your students may have lost interest by then...

Everyone will have their own opinion.  This is just my two cents.  

Sure, you bet!

I can't comment on the level of difficulty of Fire Quartz.  I have not tumbled it before.  Some quartzes suffer from instability due to composition or heat treatment.  Perhaps another member can chime in if this a good choice?    

I buy most of my grit in bulk, and I don't really care about the quality until I get to polish.
When I was running *small* Rotary Tumblers only-I was using:

Stage 1 Coarse: #80 Silicon Carbide (#60 if I could get it cheaper)
Stage 2 Fine: #120/220 Silicon Carbide (or #120 or #220-whichever is cheapest)
Stage 3A Pre-Polish: #500 Aluminum Oxide or #500 Silicon Carbide (Whichever is cheapest)
Stage 3B (Optional) Pre-Polish 2nd round: #1000 Aluminum Oxide
Stage 4 Polish: #8000 Aluminum Oxide-TRS  (TRS = The Rock Shed)

You will use more Coarse grit than any other type-because that is where your rocks will spend the most time.

I have not tumbled Blue Quartz either:  It is my understanding that the blue is usually caused by fibrous magnesioriebeckite or crocidolite...I have NO idea what that does to the tumble Lol!  

I was just recommending Regular Quartz, Smoky Quartz, and Rose Quartz because I know it is pretty common and easy to get good results in a rotary.  There are several types of quartz variants that are not easy to tumble-they chip-they fracture-you get them to polish and then they crack and ruin the batch and you are back to Stage 2.   There is also crackle quartz and dyed quartz which is a mess to tumble because it is unstable.

The great thing about rock tumbling as a hobby is that there is always something new to learn.  If I was just starting out though: I would want to build my confidence with easy stuff and then once I know that I am doing everything right: move on to more challenging tasks.  A lot of people fall into the trap of trying to polish difficult stones in the beginning, fail, and lose interest...if I was a teacher I would try and avoid this in the classroom....  

Thank you so much! I definitely tell my students that this is also new to me and we are all learning at the same time and we may fail! I also emphasize that we will keep trying haha! I try to encourage a bit of failing to figure out what went wrong. I found the grit you recommended and the rose quartz as well to test out first! Its good prices I feel as well. I am going to order 2 pounds and hope thats enough for 19 kiddos to be able to each take one home. I also am going to get the grit too! Thank you again for the advice! I feel a lot better on the starting out slow part! Just figuring out where to slow start was tough! I am glad I found this group!

You may want to check out Michigan Rocks on Youtube. Rob does a lot of great videos on learning how to tumble.

Hi from Australia

I envy your students. We never did anything cool with rocks at school.

First of all, good for you doing this with your class. You’re doing well so far and sounds like you have an order into the rock shed or similar. As mentioned once above, Bahia agates are fantastic for a class rooms tumbling experience. They tend to tumble fast and well. Few two are alike so they give a neat variation, and they are fairly cheap. Other agates can take much more time to tumble, I mean months in course grit alone. Quartz type rocks can be difficult or downright irritating at first. You may have better luck but if not, don’t get frustrated. Just get different rock. Remember, above all this is a lesson in patience so keeping it interesting is the challenge.

There are many recipes for tumbling on this site, but here's a basic one:
3 tbl stage 1 grit (60/90 silicon carbide) Run as long as it takes to get the shape you like, (most of your time will be spent here).
3 tbl stage 2 grit (120/220 silicon carbide), 1 week.
3 tbl stage 3 grit (500 silicon carbide), 1 week.
3 tbl pre-polish (1000-1500 aluminum oxide), 1 week.
3 tbl polish (most use aluminum oxide polish, but you may use tin oxide, cerium oxide) 10-14 days.
I like to burnish between each stage. That is, after a cleanout, I will run the rocks with ivory soap and clean water overnight.
This should work pretty good for you. 

Mike

Sounds like you and your students are well on the way. You have come to the right place to ask questions and get lots of help.

One thing that has not been mentioned and that you most likely already know but here it is (possibly again)

When you do the "washouts" between stages, DO NOT wash your slurry down the sink or into any plumbing  ... it will settle and harden and plug up the pipes.

One other thing ... when you get to the "burnishing" (which is washing between and after stages) many use Borax and Dawn liquid and find that it really makes a difference in final results.

I have a Chicago Tumbler and after having two lemons know more what to look for ... it should NOT be incredibly loud ... all you can really hear is the sound of  tumbling rocks . Being sure to oil the ends of the  turning spindles with a light machine oil (not WD40) between stages  and making sure that the belt tensions are right should keep you all good to go. 


Happy tumbling!