meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Jun 26, 2010 2:34:07 GMT -5
Does anyone have any experience using an additional stage of 1000 Silicon Carbide grit in rotary tumblers? Do the rocks come out shinier than the standard 600 --> polish method?  |
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Brad
starting to spend too much on rocks
Member since July 2006
Posts: 161
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Post by Brad on Jun 26, 2010 7:16:39 GMT -5
I do not have this experience, but I'm pretty sure the results would depend on the type of rocks.
Almost all of what I tumble is some variety of chalcedony (agates, jaspers, etc.). For them, I use only 60/90 grit. After five weeks, the rocks and the grit have all worn down to the point that the rocks are ready for polish (two weeks in Ivory soap) and the grit is ready to be discarded.
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meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Jun 26, 2010 8:46:00 GMT -5
I don't understand how such hard stones could be ready for polish after only 60/90?
Additionally, I thought any type of grit is worn down after 10 days or so?
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Post by johnjsgems on Jun 26, 2010 9:07:16 GMT -5
S/C breaks down but stays sharp so will get finer and finer. I had a neighbor that only tumbled Montana Moss agate and only used 60/90. He threw in a spoonful every few days and ran it at least 30 days. The tricky part would be keeping slurry from getting too thick. With your 600 you could run it a little longer and it would be 1000 or finer. I've tried only 60/90 and not washing out between 60/90 and 220 and both work fine with agates/jaspers.
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meta7
starting to spend too much on rocks
Member since June 2010
Posts: 164
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Post by meta7 on Jun 26, 2010 12:54:46 GMT -5
So how many days/weeks (approximately) does it take for a grit to work at the next finest level?
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snuffy
Cave Dweller 
Member since May 2009
Posts: 4,319
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Post by snuffy on Jun 26, 2010 13:27:05 GMT -5
In my 12lb'er, I run coarse 1 week, washout, recharge coarse again 1 week, sometimes a third recharge. After the last recharge,I let run for 3 weeks,then I go to polish. Works great for me.The grit after 3 weeks seems to be broken down fine.
snuffy
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Brad
starting to spend too much on rocks
Member since July 2006
Posts: 161
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Post by Brad on Jun 27, 2010 16:19:09 GMT -5
Meta7:
In regards to your 1st question: I agree w/ John's answer. The 60/90 grit doesn't go away, it just breaks down into smaller pieces. The difference between 60/90 grit and 600 grit is that the 600 grit has smaller pieces. It seems to me to be wasteful to get rid of one batch of small pieces of grit and replace it with another batch of small pieces of grit.
In regards to your 2nd question: I have no idea. I just know that by the end of five weeks, the rocks are ready for polish. That means that the grit must be broken down enough to do the job of fine grit.
I have to confess that I have modified the simple "5 weeks in 60/90, then polish" system a bit. I found 2 problems with that technique: 1) many rocks were not rounded enough, and 2) many rocks were getting chipped. In hopes of dealing with those problems, I added some steps. Here is the full process that I'm trying now in my 12# tumbler:
1. Start w/ 9# of rock, 1 cup (about 1#) of 60/90 grit, & enough water to almost cover the rocks.
2. Run 2 weeks.
3. Pour out most of the slurry. Add 2# of rock (preferably either small pieces or ones that are already somewhat rounded), 1 cup of 60/90 grit, and water.
4. Run 2 weeks.
5. Add 2# of rock (preferably rock that is already well rounded).
6. Run 3 weeks.
7. Clean up & get ready to polish.
This produces about 10# of rock. I split that up into two batches for my 6# polish barrel. Seems to work pretty well so far.
(This looks pretty similar to snuffy's system. I might have to try shortening steps 2, 4, & 6.)
Please let me know if you have any questions about this.
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revco
starting to spend too much on rocks
Another Victim Of The Rockcycle
Member since February 2010
Posts: 162
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Post by revco on Jun 28, 2010 2:43:16 GMT -5
Funny you should ask!
I fairly recently started using a 1000AO stage in my process and completed my first batch with it in the mix about two weeks ago. While I wouldn't say that this batch had more gloss, although there were some differences in quality (for the better), it did help with one aspect. I've been really focusing on trying to get mixed batches down and have been trying different methods/materials. I felt that the 1000AO stage helped because I had a far larger success rate than I've found typical in previous mixed batches where a single pre-polish was used prior to polish. My estimation is that it helped lay down a better foundation for the polish and may have helped rocks that are typically not great with just CO take a better polish. It's hard to say that it also couldn't have been the rocks in this batch or perhaps even the additional burnish stage prior to the 1000AO.
It is true that you could just extend a 500/600 load of SiC for another week or so and I'd bet it would provide a similar result. Snuffy's method would work as well due to the properties of SiC and how it breaks down. When I run out of 1000AO, I will be trying a longer 500 pre-polish and comparing results to see if the AO truly adds anything to the mix or whether the fine particles are what matters.
P.S. I would argue against any kind of "recipe" as far as time for the rough stage. They're ready when they're ready and it's different for different types of rocks and personal preferences. Some take 3 weeks, some will tumble for months until they're ready! I've got some agates turning right now that seem to have been in the tumbler almost 3 months!
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Post by 150FromFundy on Jun 28, 2010 13:04:41 GMT -5
I always use 1000 Aluminum Oxide prior to my Polish with lots of ceramic media in my UV-10. After a few days in 1000 AO, they almost don't need the polish when they come out. I have a better oveerall success rate with a UV-10 batch (250 to 300 pieces) when I do the extra step.
Darryl.
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Post by rocklicker on Jul 2, 2010 13:20:08 GMT -5
I use multipule grits instead of just 60/90. Some people here use 1000 grit as a prepolish. I prefer tripoli powder because it's cheaper and you can use less.
Still keep meaning to try a two grit stage, but stick to the usual grits. Old habits die hard I guess.
Steve
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Post by Jack ( Yorkshire) on Jul 5, 2010 0:35:02 GMT -5
Hi
I agree with this from revco totaly
[glow=red,2,300]P.S. I would argue against any kind of "recipe" as far as time for the rough stage. They're ready when they're ready and it's different for different types of rocks and personal preferences. Some take 3 weeks, some will tumble for months until they're ready! I've got some agates turning right now that seem to have been in the tumbler almost 3 months[/glow]
I gererally run my rough on the "assembly line system" when they are ready they come out and fresh stones go in to make up the load , everytime I recharge
Works for me
I havent run 1000 in the rotary but do in my Vibe, I know grit breaks down but there is always the problem in long runs of mud getting in the way of a good grit cut ,
Or that is what my mind works out I may be wrong others please comment
Jack
Yorkshire uk
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Post by Toad on Jul 5, 2010 8:01:14 GMT -5
I agree with Jack, the rocks are ready when they're ready. Why move rocks on that have obvious defects that won't be removed in subsequent stages?
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slabcabber
has rocks in the head
Member since April 2010
Posts: 590
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Post by slabcabber on Jul 5, 2010 8:19:55 GMT -5
I have figured out one thing, everyone has different recipes for tumbling But I go back to this... The length of time it takes has a lot to do with the tumbler you use, and what your tumbling. If I left this batch of Arizona petrified wood I am doing now in the tumbler I am useing in 80 grit for 2 weeks there would be nothing left. I go 5 days to one week in 80 then 5 days to one week in 220, 5days to one week in 600,5 days to one week in polish ( T/O, A/O, C/O, depending on the stone ) and 24 hours in borax, and so far has worked out great for me. I know the graded grits cost more but as of now that is what I am useing..... And I like the end results
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