Post by aDave on Nov 16, 2019 22:01:16 GMT -5
Who knew tumbling was gonna be so hard? I thought 'You puts the rocks and grits in the barrel and hit go!' I knew I shouldn't have put those NatGeo rocks in with the pack I bought from that rock store, but I wanted a bigger variety. Some rocks are now ground to nothing, and some are barely affected. I'll post some pics when I figure out how to get around work's website security.
I'm having fun too, even when I'm looking through my yield and going hey wait, weren't these 300x bigger!?
This is probably going to be a long post, so please bear with it. If it falls within TLDR, the end summary is don't follow Nat Geo's instructions (and material provided) if you are looking for polished rocks. If you use their stuff, that's not going to happen.
These two quotes of yours really go to what I alluded to in my first reply to you. Sure, my reply wasn't detailed enough to address all of these concerns...I only spoke to sub-par instructions as it relates to the real world. There are a number of different variables as it comes to providing a (successfully polished) finished product, and what you were given by Nat Geo with instructions and material is not something you can get good results from. Instructions from Nat Geo aren't the only ones lacking. Lortone, for instance, also mentions that a coarse run can be accomplished in one week. It's all well and good that's mentioned, but real world results say otherwise.
First, let's speak to what you have seen after only three days in a coarse grind. You mentioned you have rocks that are nicely shaped, well rounded, and are seemingly ready to move on after only three days in the coarse grind. What you found may be true, but if I found what you did, there would be huge red flags. Let me digress a bit.
For the beginner, most of us here would recommend jaspers, agates, quartz, and other hard stones that are typically on the Mohs scale around 7 or more. Such material usually produces nicely finished material at the end of the polish stage. However, to get this stuff well rounded, less flawed, and almost crevasse free, it takes weeks, if not months to do so. This is especially true in a tumbler such as yours, as a 2 lb tumbler can't process material as fast as larger tumblers. If your material is being rounded after only 3 days, there's a problem with it. Mainly, this means it's too soft...probably at a Mohs scale of 5 or less. In pretty much no uncertain terms, such rocks won't polish in a rotary tumbler.
My suggestion to you is to pull the material and live with smooth and matte finished rocks. Don't waste your grit and continue them. They won't polish no matter what you do.
So, what should you do? I would look to obtain material that is a known quantity. I truly believe that Nat Geo provides its rocks without regard to final product, and the material is truly a hedge against customers who buy their stuff and ultimately complain about bad results. They'll be able to point to some rocks being rounded, but when there is no polish, it can be blamed on the consumer (since some shaping took place.)
Nat Geo (IMHO) is selling a sub-par product with sub-par material which really cheats the consumer at the end of the day. When nothing comes out polished based upon what was provided, they can simply point to user error since (too soft) rocks have been shaped. That's my opinion.
Where should you go from here? Get rid of any material that was provided with your kit. It probably won't polish at the end of the day. You can stick with the grit kits you were provided, but I'd recommend going to some place like the Rock Shed to get your grit. Nat Geo simply provides different packs without any information about the size of the grit. That's important...more important than simply listing a stage for the grit use.
For example, I believe their grit pack may be labled as "polish." That's all well and good, but without knowing the size of the grit, you may be getting cheated at the end of the day. In regards to rocks and grit, size matters. I'd never use a grit pack labled a particular way. I look for particular sizes. That's just me.
I hope this helps you a bit. Thanks for your description of what is happening to your rocks (from Nat Geo) after only a few days. Most folks who come here to complain about not getting a polish on said material did not provide such details as you did. This is very helpful at the end of the day.
We, here on RTH, have often speculated that the rocks Nat Geo provides may not even be able to be polished. You've pretty much confirmed this in that you are seeing stuff rounded after only three days and nearly disappearing. Good material that will take a polish will take far longer than that.
You may still be able to use your tumblers down the road, but you'll have to make some adjustments.
Get good known (hard) material that is 7 or better on the Mohs scale. Get new grit, focusing on extraordinary amounts of 60/90 SiC when compared to other grits for remaining stages. For your size barrels, start with 5 lbs of 60/90 SiC, and then smaller amounts of 120/220 SiC, 500 AO, and then 13,000 to 14,000 AO polish. I could weigh you down with other info, but start with this.
AO is aluminum oxide, SiC is silicon carbide.
Good luck.