vance71975
freely admits to licking rocks
Member since September 2022
Posts: 760
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Post by vance71975 on Jul 22, 2023 10:43:16 GMT -5
Couple good smacks with a 3lb crack hammer and it will roll just fine lol.
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Post by Son Of Beach on Jul 22, 2023 18:37:09 GMT -5
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Post by Bob on Jul 23, 2023 21:21:09 GMT -5
You took good photos for us. I do a lot of large rocks. I recommend against this and predict extremely poor results if you go ahead. It will also take more than a year to get best results if was not slightly too large. By best, I mean no defects of any kind.
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Post by HankRocks on Jul 24, 2023 4:39:16 GMT -5
Here are two large rocks I have tumbled in a Model B, they were both in the 4 pound range at the start, I seem to remember it taking somewhere between 2 and 3 months from start to finished product. I had a mix of rock running with these two during coarse runs, moved to smaller rocks for final polish. The first is a river tumbled piece of Petrified wood which would be considered pre-tumbled thanks to the river; IMG_2622 by Findrocks, on Flickr IMG_2676 by Findrocks, on Flickr IMG_3373 by Findrocks, on Flickr IMG_3393 by Findrocks, on Flickr The next is a large beat-up Arkansas Quartz crystal, pictures do not do the finished product justice; tried to make a video of the finished product on one of the changing color light stand; IMG_0997 by Findrocks, on Flickr IMG_1805 by Findrocks, on Flickr IMG_2773 by Findrocks, on Flickr As I said the Petrified wood was decently pre-shaped by nature and I do not mind leaving some of the wood character, holes and some indentions. Quartz crystals tumble very fast and the smoothing process is much quicker than most Agates or Jaspers
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Post by Son Of Beach on Jul 24, 2023 19:14:29 GMT -5
I guess there is only one way to find out.
To Bob's point, yes, it's probably going to take a very long time, especially if you are looking for a nice finish. Those pits in the bottom have to go that depth all the way around andthat's a lot of rock to chew thru.
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,592
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Post by dillonf on Jul 24, 2023 19:24:55 GMT -5
Here are two large rocks I have tumbled in a Model B, they were both in the 4 pound range at the start, I seem to remember it taking somewhere between 2 and 3 months from start to finished product. I had a mix of rock running with these two during coarse runs, moved to smaller rocks for final polish. The first is a river tumbled piece of Petrified wood which would be considered pre-tumbled thanks to the river; IMG_2622 by Findrocks, on Flickr IMG_2676 by Findrocks, on Flickr IMG_3373 by Findrocks, on Flickr IMG_3393 by Findrocks, on Flickr The next is a large beat-up Arkansas Quartz crystal, pictures do not do the finished product justice; tried to make a video of the finished product on one of the changing color light stand; IMG_0997 by Findrocks, on Flickr IMG_1805 by Findrocks, on Flickr IMG_2773 by Findrocks, on Flickr As I said the Petrified wood was decently pre-shaped by nature and I do not mind leaving some of the wood character, holes and some indentions. Quartz crystals tumble very fast and the smoothing process is much quicker than most Agates or Jaspers Those came out real nice!
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Post by tims on Jul 24, 2023 20:21:49 GMT -5
HankRocks I followed the big pet wood tumble and was impressed with the result. Thinking this might be a good winter project since it won't require frequent cleanouts just lots of recharges and time. Though I'm having a hard time convincing myself this rock is worth the $ in grit, electricity, and time, even if it could finish with a decent polish.
Son Of Beach if this does get rolled I'd be happy to have the "top" 3/4 or so smooth since that's where it's got pretty banding. The divots out near the rind don't bother me. And besides us, no one else is likely to ever see it.
I appreciate all the input from everyone. Figured this was a quick fail and was fully prepared to let it go but you guys don't seem so eager to give up. Will spend some time going back through your suggestions and checking out the big boy tumble threads. If it clicks will give it another go.
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Post by HankRocks on Jul 25, 2023 5:12:28 GMT -5
HankRocks I followed the big pet wood tumble and was impressed with the result. Thinking this might be a good winter project since it won't require frequent cleanouts just lots of recharges and time. Though I'm having a hard time convincing myself this rock is worth the $ in grit, electricity, and time, even if it could finish with a decent polish.
Son Of Beach if this does get rolled I'd be happy to have the "top" 3/4 or so smooth since that's where it's got pretty banding. The divots out near the rind don't bother me. And besides us, no one else is likely to ever see it.
I appreciate all the input from everyone. Figured this was a quick fail and was fully prepared to let it go but you guys don't seem so eager to give up. Will spend some time going back through your suggestions and checking out the big boy tumble threads. If it clicks will give it another go.
One thing you need to consider is that with the large rock in the batch, there should be an increased amount of grinding of the accompanying rocks. To me it's a "hammer" effect. It will provide more pressure on those smaller rocks and grind them down quicker, creating more slurry. This is my theory based on some observations. It also means that you may still need to do some cleanouts otherwise the slurry would get two thick. You will be able to tell when you add more grit. I try and use this effect mainly in the 1st stage where increased grinding is desired. For subsequent stages I move to using smaller rocks as the fill which increases the cushioning factor. Think about dropping the big rock into a bucket of 1" to 2" rocks, there is going to be damage inflicted on all of those surface rocks and even the large rock. Now drop the big rock into a bucket of pea gravel, there is a lot more cushioning with the little rocks able to absorb better. What you could do is that if you do 3 or 4 cleanouts, set aside the smalls that are shaped after each coarse run and then for 2nd stage add them all back in replacing some of the bigger rocks, making your own bucket of pea of pea gravel. The above is all my theory and based on the the type and mix of rocks involved. You may observe slightly different effects with your batch. That's why I like cleanouts, I want to see what's going on in that barrel. and...remember, It's your rock to tumble, you decide when it is done and how much to grind.. In my case the petrified wood had a somewhat porous side that I knew I was not going to completely remove so I didn't. It also has a couple of soft streaks that do no take as high a polish. No matter to me as they all add character. The quartz on the other hand was going to go to smooth with less effort and so it did. And... I never considered how long it would take and I wasn't worried about wasting time, It was something I wanted to do. There is a good chance I will never sell those two. For my situation with 3 Model B's and being retired and having a ready supply of tumble material it was a "let's do it" decision. Been setting aside larger pieces as potential candidates for future "Big Rock" tumbles. Some I may take to perfection, others some of the flaws may stay. I have rambled long enough and I need to get ready for a scan for one of those pesky doctors!!, good luck and keep us posted. Henry
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Post by Starguy on Jul 25, 2023 11:45:53 GMT -5
Glad you weighed in on this one Henry HankRocksI think that rock can be successfully tumbled in the 12 pounder. I typically run stage 2 through polish in 3 pound barrels. They would definitely choke on that size rock.
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Post by Starguy on Jul 25, 2023 22:22:27 GMT -5
timsThis thread has been keeping me thinking. I’m glad you started it. I have a pretty big agate rolling in coarse. There isn’t a problem in the 12 lb barrel. It’s getting close to ready for stage 2. I’ll try to finish it in a 3 lb barrel in which case, it will look like your rock in your 12 lb barrel. The plan is to use all agate to fill around the bigger rock. I’ll probably limit the amount of medium size rocks and fill to 3/4 full plus a little with smallish agates. There will be a little volume loss in 220 and a tiny amount at 600. The rocks will have to play nice together for three weeks or longer. I’m pretty optimistic since it will be all agate.
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hplcman
spending too much on rocks
Just getting into this....
Member since August 2022
Posts: 413
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Post by hplcman on Jul 26, 2023 10:18:27 GMT -5
tims This thread has been keeping me thinking. I’m glad you started it. I have a pretty big agate rolling in coarse. There isn’t a problem in the 12 lb barrel. It’s getting close to ready for stage 2. I’ll try to finish it in a 3 lb barrel in which case, it will look like your rock in your 12 lb barrel. The plan is to use all agate to fill around the bigger rock. I’ll probably limit the amount of medium size rocks and fill to 3/4 full plus a little with smallish agates. There will be a little volume loss in 220 and a tiny amount at 600. The rocks will have to play nice together for three weeks or longer. I’m pretty optimistic since it will be all agate. Would you consider finishing it off in the 12 lb barrel? You could do the same thing with adding a bunch of smaller agates and then not worry about how the movement would be as you would using the 3 lb barrel to finish it off?
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Post by Starguy on Jul 26, 2023 10:51:27 GMT -5
tims This thread has been keeping me thinking. I’m glad you started it. I have a pretty big agate rolling in coarse. There isn’t a problem in the 12 lb barrel. It’s getting close to ready for stage 2. I’ll try to finish it in a 3 lb barrel in which case, it will look like your rock in your 12 lb barrel. The plan is to use all agate to fill around the bigger rock. I’ll probably limit the amount of medium size rocks and fill to 3/4 full plus a little with smallish agates. There will be a little volume loss in 220 and a tiny amount at 600. The rocks will have to play nice together for three weeks or longer. I’m pretty optimistic since it will be all agate. Would you consider finishing it off in the 12 lb barrel? You could do the same thing with adding a bunch of smaller agates and then not worry about how the movement would be as you would using the 3 lb barrel to finish it off? I think that finishing in the 12 pounder would be the smart thing to do. I don’t know if I have the patience to wait until there is enough material finished in coarse to fill the 12 pounder. I kind of like the challenge too.
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Post by Bob on Jul 26, 2023 11:42:35 GMT -5
Part of the reasoning for my time period comment was because of severe pitting not in the side of the piece, but on the edge of the piece. Getting those ground out takes much longer than if on the side. In fact, they can take so long that the rock can end up getting thinner than desired. A rock that almost is as wide as the barrel can experience very little edge grinding. This one reason I got a trim saw. I ruined too many large rocks by keeping going and going and going in rough grind until done and that 1/4" deep pit was gone, but in the process lost a whole lot of the rock that really didn't need any rough grind. In some cases, I lost pretty patterns and other features. Grinding out a 1mm pit in an edge can result I've learned in losing 2mm or more on a broad side.
I would trim quite a bit off that rock today if it was in my process using my 10" lapidary saw. There would be 1 week in rough grind to get the surface where I could clearly see things and make decisions, then I would take a Sharpie and make my saw cut marks and do it. Then another week in rough grind, then another saw cut if needed until I got all the sawing done. I don't like to saw off any more than necessary so often takes several goes like that to get it just the way I like it.
However, once rough grind is done, a large rock like that can process fine it seems in successive smaller grits, provided sufficient smaller pieces can circulate around it. This is one reason I not only have a succession of grits, but a succession of barrels. I have 40, 20, 12, and 6lb barrels. Almost everything starts in the 40, but after rough done, those rocks will go to the 20 or 12 next unless too big which is rare.
The plastic pellets are sufficient for circulation of grit I've learned, but not in grit larger than 220. So I use rock smalls in rough grind and 80, then in 220 I can take a rock that is almost as wide as--for instance--my 12lb barrel and do 220 or smaller in it with plenty of plastic pellets if my other material needing that grit size aren't small enough to circulate well. Weird things happen if plastic pellets are used with grit larger than 220--no matter what barrel size--at least that's been my experience so I avoid it. (I actually had some batches where almost nothing happened in a week and the grit was still there.)
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Post by tims on Jul 26, 2023 13:11:01 GMT -5
Starguy keep us updated. I've got some egg size and a bit larger quartz cobbles in the 12# now with a mix of really rough stuff, and was actually considering finishing them in 3# just because they're smoothing up already and the rest of the batch has a long way to go. Still have a couple weeks before the 3# is empty though it's got some of my most precious little tepees rolling right now.
Bob I do appreciate your input and agree about the pits on the "bottom" edge of that agate; to roll them out would take forever. That edge of the rock is thicker than my 10" will cut without flipping the rock and i'm afraid i'd just make a mess trying to trim it. Was thinking maybe could grind them out with the 110 hard diamond wheel but it'd be a lot of grinding. Will stew on it some more. And as mentioned, those pits wouldn't bother me a bit if the sides polished up ok.
Pondering on this rock i'm now concerned by the banding, it's a bit undercut between bands in its naturally smoothed state. Thinking the undercutting might get substantially worse in a long stage 1.
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Post by Starguy on Jul 26, 2023 14:35:26 GMT -5
timsWill do on the updates. It’s not as big relatively as yours but it’s going to be a dominant force in the batch. I still have a couple weeks before a decision on it needs to be made.
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Post by Bob on Jul 26, 2023 15:57:05 GMT -5
I do appreciate your input and agree about the pits on the "bottom" edge of that agate; to roll them out would take forever. That edge of the rock is thicker than my 10" will cut without flipping the rock and i'm afraid i'd just make a mess trying to trim it. Was thinking maybe could grind them out with the 110 hard diamond wheel but it'd be a lot of grinding. Will stew on it some more. And as mentioned, those pits wouldn't bother me a bit if the sides polished up ok.
In that case, you might enjoy the following technique. Clean out those pits as best as you can if they are not clean. I have an assortment of dental picks which work great. Turn on the oven, let it get to 100 degrees, then turn it off. Put the rock in there for maybe 10-15 mins. It will get warm. Now, mix up water clear 330 epoxy, and with rock tilted up start on the pits. It might take several times to get them all done. The warmth causes it to cure faster, but more importantly helps it to get runny when put in the pits and also helps bubbles come out, but don't delay after mixing before putting it in the pits or else the epoxy will start to get stiff and not penetrate as well. I use a toothpick to help work it down the sides of pits so as it starts filling sort of from bottom and doesn't trap a large bubble down there. After curing, you may find you are very happy with how it all turns out. Sometimes the epoxy plugs stay there and grind well and also polish well. Sometimes not. I've never tried that with pits larger than a pencil diameter, and they are usually smaller. I have no idea if it would work on large pits. I use this now regularly between 1,000 grit and polish. If there is a rock with 1 or 2 pinholes, and I hate to put it back in rough grind to make it perfect, I will do this and those pits often disappear and are hard to find coming out of polish. I've learned to have the epoxy in the pit just a tiny bit higher than the surface of the rock around it.
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