First batch in stage 4 - pew....

[chaosdsm]

So I've used silicon carbide for the first 3 stages, ending with 500/600 mix.  No smell through those stages.   

Then I get to Stage 4, I'm using MJR Tumblers 12,000 grit Aluminum Oxide - I thought it was 1,200 grit when I ordered the kit....  I used about 1/2 as much powder as I needed in the first round, I noticed a slight odor when I checked it after 7 days.  I then added the right amount, and 7 days later, it smells like someone puked in the drum then tumbled it overnight.  

Only other thing different, is I'm using felt polishing pads (1/2" cylinders for Dremel) as filler.  I've never smelled anything like this from wet felt.  I have 2 unopened packs of the felt left, and when I smell those, I don't detect any smell coming from them.  However, when I smell the jar of 12,000 grit AO, it does give off a slight odor...  Is this normal for Aluminum Oxide?   

As a test, I put some water in 1 of the packs of felt and sealed it again to see if it develops a similar smell in a couple of days.

[saaz]

First, be glad you got 12000, that's actually better for the final polish. For some rocks, I've seen 1200 recommended as an additional step, but I think most people generally jump to 8000 or so.

I've never noticed any weird smell from AO, so I suspect your felt pads.

[chaosdsm]

Jul 1, 2024 16:46:08 GMT -5 saaz said:

First, be glad you got 12000, that's actually better for the final polish. For some rocks, I've seen 1200 recommended as an additional step, but I think most people generally jump to 8000 or so.

I've never noticed any weird smell from AO, so I suspect your felt pads.

Almost all the "grit kits" I've seen, have 1200 AO as a "final polish". 

The MJR kit I got is the only one I found with a really fine grit so far.   I think 1200 would have been much better, or at least much faster.  12,000 after two weeks has barely made any noticeable progress.  I put it back on for another week at speed 3 on the tumbler, maybe it will at least burnish the rocks...  

I did find some 1500 grit SiC, should be here next Monday.  If I don't see noticeable difference by then, I'll switch to the 1500, then go back to the 12,000 grit after. 

[HankRocks]

I assume you are tumbling the rocks. Questions, what size grit did you use for the first 3 stages? what type and size tumbler are you using? and is it new? and what type of rocks are you trying to polish? I assume you emptied the rocks after each SiC stage and washed them before running the next stages.

As noted by saaz 12000 Ao is a real good polish. 1200 Ao is not a polish although some vendors include it as such, everyone switches to 12000 after not getting proper results with the 1200. 

I have never smelled anything from AO or SiC for that matter.

[chaosdsm]

In stage 4 are: Agate, Topaz, Garnet, Jasper and a half dozen unknowns.  

36grit SiC > 80/90grit SiC > 220grit SiC > 400/600grit SiC > 12,000grit AO 

Rinsed, brushed, examined between stages

This batch was only rotary tumbled for all stages. Rest of my rocks are going into vib tumbler after the 80/90 grit.

The 1500grit SiC came in early, so I cleaned & rinsed the batch, no noticeable change in the rock texture.  Then I put 3oz of the 1500 SiC in the 3lb drum and put it back on highest speed.  I'll check it again next Monday (next day off), to see what kind of progress the SiC makes.

[Wooferhound]

Jul 3, 2024 14:03:25 GMT -5 chaosdsm said:

The 1500grit SiC came in early, so I cleaned & rinsed the batch, no noticeable change in the rock texture.  Then I put 3oz of the 1500 SiC in the 3lb drum and put it back on highest speed.  I'll check it again next Monday (next day off), to see what kind of progress the SiC makes.

SiC will not polish rocks no matter how fine it is , I've tried.

forum.rocktumblinghobby.com/thread/78394/using-recovered-slurry-polish-experiment

[chaosdsm]

Jul 4, 2024 9:05:37 GMT -5 Wooferhound said:

Jul 3, 2024 14:03:25 GMT -5 chaosdsm said:

The 1500grit SiC came in early, so I cleaned & rinsed the batch, no noticeable change in the rock texture.  Then I put 3oz of the 1500 SiC in the 3lb drum and put it back on highest speed.  I'll check it again next Monday (next day off), to see what kind of progress the SiC makes.

SiC will not polish rocks no matter how fine it is , I've tried.

forum.rocktumblinghobby.com/thread/78394/using-recovered-slurry-polish-experiment

Mild water flow will carry even large(in relation to SiC grit) heavy pieces of gold (6x as dense as SiC) a very long distance if there's no place for it to get trapped.  Unless you're using filter screens to filter through different grit sizes, your recovered slurry can easily have grit sizing ranging from 200 to 50,000 grit, so basically all the coarser grits in the slurry are making it impossible to polish.  You'd need to filter your slurry through at least a 500 mesh screen to get a "polishing grit" without having the coarser grits included.  

Here's a Petosky waiting for stage 4, this is pretty much how all my rocks in stage 4 looked after finishing with the 12,000 grit - unchanged from when they went in.

very flat/matte no shine at all.

Here's one of the harder rocks after a 5 days in 1500 SiC:
  

Only thing I did was rinse it off, scrub it with a toothbrush, then use some denatured alcohol & a shop towel to wipe it down to ensure that there was no oils from my fingers giving a false shine.  The white line is the overhead LED shoplight, notice that it doesn't show up at all on the Petosky.   While it's still not polished (wouldn't be after just 5 days), but it is definitely showing significant improvement with a satin like shine to it!  Tigers eye from the Nat-Geo kit has also taken a strong satin shine to it, even better than this rock.  Most of the quartz, agate, and amethyst are closer to semi-gloss at this point!!!

[dshanpnw]

I would have to agree with saaz that I suspect the felt pads to be the smelly culprit. It could be all the different types of rock dust, water, the grit, and tumbling action in a closed barrel combined with the felt pads. Anxious to hear what becomes of the little test. You could always remove the felt pads and try stage four with the 12,000 grit again.

[chaosdsm]

Jul 4, 2024 9:05:37 GMT -5 Wooferhound said:

Jul 3, 2024 14:03:25 GMT -5 chaosdsm said:

The 1500grit SiC came in early, so I cleaned & rinsed the batch, no noticeable change in the rock texture.  Then I put 3oz of the 1500 SiC in the 3lb drum and put it back on highest speed.  I'll check it again next Monday (next day off), to see what kind of progress the SiC makes.

SiC will not polish rocks no matter how fine it is , I've tried.

forum.rocktumblinghobby.com/thread/78394/using-recovered-slurry-polish-experiment

5000 grit SiC will put a mirror-like shine on most metals, pretty sure 10000 grit SiC will polish hard stone very well, and I'm gonna find out!  

[pebblesky]

It would be fun to experiment on 10000 grit SiC. Some earlier threads are helpful in understanding the difference between SiC and AO in polishing: forum.rocktumblinghobby.com/thread/91807/1200-silicon-ccarbide-aluminum-oxide

[chaosdsm]

Here's a few from the last round of the 1500 grit.  First one is shinier than it looks, actually, all of these are shinier than they look in these photos.

Looks almost satin in this photo but it's closer to semi-gloss


The rest are definitely glossy - Montana Moss Agate:


Another Montana Moss Agate:


Chunk of mostly Quartz: cut off of a larger Agate


After drying off with paper towel, I used on old soft t-shirt to burnish each rock for about 15 seconds.  So yes, the 1500 grit SiC does a very nice job of leaving a smooth surface that can be glossy after burnishing step.