meviva
Cave Dweller
Member since July 2013
Posts: 1,474
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Post by meviva on Dec 10, 2013 11:01:23 GMT -5
Hi,
I thought I finally had enough rocks to go to final polish. Then I started looking at picture on here. I am going through my rocks and have decided to put most of them back in 60/90. Lots of them have pits, cracks or are chipped. Some have a gash that looks like someone took a knife and just sliced at it. I know that a lot of the gashes weren't there going into pre polish. That batch had plastic pellets in it and don't know why they are gashed or chipped. I think I moved a lot of them on because I was afraid they would grind down to nothing, and a lot of them that were good are now chipped. How do you decide which ones to move on? Do you wait for perfection in 60/90? Or move along your favorites even if not perfect just to save them?
I know a lot of these will be gone or too small to bother with after they go through 60/90 again. I guess they will just have to sacrificed as smalls for the bigger ones that still have hope of improving. Some of the imperfections aren't too bad and hopefully will smooth out soon. I started tumbling at the end of July and don't have anything finished yet. I really appreciate all of the input that I have gotten here.
Thanks
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Post by Drummond Island Rocks on Dec 10, 2013 11:53:28 GMT -5
Sorry to hear your having a hard time with it. I do run most of my stuff in 60/90 till all imperfections are gone but there are also times where I like a certain feature showing on the rock and if I continue to 60/90 tumble I might lose them so in those cases I do move stuff on that is not 100 percent perfect. You just have to pull those ones aside at each cleanout to make sure all the pits/cracks and voids are cleaned out real good before moving them on.
You did not add a picture or describe what type of rocks you had in there but I hardly ever get damage at pre-polish. I do always have 25-30 percent of my volume filled with ceramics at that point though.
Chuck
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meviva
Cave Dweller
Member since July 2013
Posts: 1,474
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Post by meviva on Dec 10, 2013 16:44:33 GMT -5
Here are a couple of pictures: Chips Gashes
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Post by Drummond Island Rocks on Dec 10, 2013 18:43:33 GMT -5
wow! looks like there was some violent action going on in that barrel for sure. Filling to 3/4 full and then adding some plastic filler in your 120/220 and 500 stages should cure that.
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meviva
Cave Dweller
Member since July 2013
Posts: 1,474
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Post by meviva on Dec 10, 2013 21:12:39 GMT -5
There were pellets in the barrel, but it was only about half full. I guess got too excited to get them done so I could add them to the others that were ready. Hard lesson learned.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,473
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Post by Sabre52 on Dec 10, 2013 21:42:56 GMT -5
Meviva, I know the coarse grind phase is boring and tedious, but it's really the single most important step in getting a good tumble batch. All those pits should be ground away. Rocks with major cracks or crevices should be broken up or discarded as yard gravel. If you go into fine grind with well rounded well smoothed rocks ( which can take six or more weeks with weekly grit recharges) you've won most the battle in front of you. Go into fine grind with pits, cracks etc, you will get polished rocks with pits, cracks etc and if those pockets full of grit are not properly cleaned between stages, you will contaminate your load and your barrel and not get a polish at all. I like to use one barrel for coarse grind, one for fine, and a third for only prepolish and polish.
I know a lot of folks here run barrels 3/4 or so full for coarse but I run half full since I run almost exclusively agate and jasper which is tough stuff. I seldom see problems. Things like quartz crystal or obsidian I run fuller only homogeneous batches with lots of plastic pellets cause those material are more delicate.
Prepolish and final polish, fuller barrels are the ticket, with lots of pellets and really a lot of small rocks, or ceramic too. The smalls increase surface to surface contact and really polish all those surfaces. If you run slabs, you will get a much better polish if you run a few slabs with a lot of smalls. I got careless recently and tried to run a load of mostly all slabettes with lousy results. Again, you need the smalls for increased contact to rub them surfaces nice and smooth and polish them up.
Don't lose heart and you will see improvement. Also helps to write down what you are doing to analyze where you screw up when you do. And you will. When a batch turns out crappy, its not bad luck, it's something you screwed up *L*......Mel
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Post by connrock on Dec 11, 2013 8:26:07 GMT -5
It's pretty hard to do small rocks that are thin to begin with,,,,especially when the edges are thin before roughing them. If the edges of a rough rock aren't 3/16"-1/4" thick you will most likely see the edges being "chipped" like yours are. The first rock that has a "gash" in it is normal and just needs to be roughed in more,,,NOTHING out of the ordinary. The second rock that has a "gash" is typical for that type of rock which is naturally "flawed" to begin with. The "flaw" that's touching your index finger will take 3-4 more times in rough to get rid of if your lucky. The "flaw" in the center of that same rock will also take about the same time to get roughed in because it looks like it's in a "concave" area of that rock and doesn't get as much "wear" in the tumbling as the edges of a rock would get. What you're seeing with the rocks that have a "gash" is normal and only take a lot of time to be ready for the next step. The thin edged rocks won't "heal" much unless you do this type of thin rock using methods that someone new to this shouldn't get into yet.
DO NOT get discouraged,,,,,it took me years before I mastered rock tumbling! You'll get there but it IS a slow process and you'll have a lot of set-backs. connrock
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meviva
Cave Dweller
Member since July 2013
Posts: 1,474
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Post by meviva on Dec 11, 2013 9:50:48 GMT -5
Thanks for the encouragement!
Sabre: When you say weekly recharges, do you mean completely washing out the slurry and starting with new grit or adding a tablespoon or two to the existing slurry?
connrock: I put all the bad ones back in 60/90. I was worried about the ones with thin edges, maybe if I had a fuller barrel and more cushioning it wouldn't have been as bad. I know it takes a long time. I'm ok with that but I was getting so close. Oh well back to square one. :/ Thanks.
Good news: I do have about a pound and a half of rock that is perfect and ready to go into final polish. I guess they will have to wait a while to get there.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,473
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Post by Sabre52 on Dec 11, 2013 10:48:02 GMT -5
meviva: As Connrock said, those thin edged ones will probably keep chipping no matter what. Re the grit changes: Yes, I totally clean the rocks and then totally recharge with grit. I did some experiments, as I used to reuse a lot of slurry to thicken the mix, and found keeping the slurry cushioned the load but also reduced the cutting action of the grit. Grind was much more efficient if I used clean rock and fresh grit every recharge. Figure on using five or six times as much coarse grit as you do fine grind, prepolish or polish. I use a bin to accumulate rocks ready for fine grind. Each time I recharge, I remove rocks ready for stage two and add more rough rock to replace what is removed. In that way, I accumulate enough nicely ground stones for a nice full fine grind load, though it may take a few weeks to do so. I have a larger tumbler I use for nothing but coarse grid and it runs 24/7, 365. I do the last three stages in a UV-10 vibe as the gentler action produces good results with ease..Mel
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Dec 11, 2013 12:54:58 GMT -5
Connrock and Mel are right on with what they've said. This does take time to "master". When I first started I thought I'd never get it. Your way ahead of me though because your asking questions.
I clean my barrels out and add fresh water grit and rock as well. I have found that in my QT66 that the grit is broken down by the 5th day so I generally do a clean out every 5 days. Running longer sometimes if I'm pressed for time on a particular day.
I think that the 1/2 full barrel was a contributor to your chips and such. Lortones instructions say to fill the barrels from 2/3rds down to 1/2. I don't agree. From 2/3 to 3/4 is better. I was roughing some Rutilated quartz in my QT66. As the volume got down I decided to let them run at 1/2 full. The directions said I could after all. I got chips and cracks in the rocks where I didn't have them before. I always keep the barrels "full" now.
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meviva
Cave Dweller
Member since July 2013
Posts: 1,474
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Post by meviva on Dec 11, 2013 13:28:00 GMT -5
Sabre: Ok good, I have been cleaning out the barrel and using fresh water and grit each time also.
tkvancil: I have a QT66 also. I have a 60/90 barrel going that is on its 8th day. I was going to wait another couple of days to open it but I guess should open it today. I think I was doing pretty well until I tried to rush it and run the half full barrel.
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Dec 11, 2013 13:43:44 GMT -5
Sabre: Ok good, I have been cleaning out the barrel and using fresh water and grit each time also. tkvancil: I have a QT66 also. I have a 60/90 barrel going that is on its 8th day. I was going to wait another couple of days to open it but I guess should open it today. I think I was doing pretty well until I tried to rush it and run the half full barrel. The 5 day cycle is my thing. I'm impatient and want fresh 60/90 as soon as possible. There is nothing wrong with letting a barrel run longer. The grit breaks down into smaller and smaller particles. It doesn't stop working but produces finer scratches. There are members here that skip the 220 step altogether by letting the rocks run in the 60/90 for an extended time period, say 10 days or more. If you are happy with your results running 8 or more days there's no need to change what's working.
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Post by Hard Rock Cafe on Dec 11, 2013 13:55:57 GMT -5
All good advice. I have one more bit to add: some rough (not necessarily yours) will continually develop new pits and vugs no matter what you do. It's just poor quality rock that is best used in a landscape.
Chuck
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herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Dec 11, 2013 15:09:51 GMT -5
I always try to let my 60/90 run at least 10 days, sometimes 2 weeks or even longer if I can't get out to check it.
Part of this is because if I am running a load of softer rock I will still have grit that hasn't broken down if I go shorter. If you are all agates and jaspers then maybe less is fine, but I always try to err on the side of waiting.
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Post by pghram on Dec 11, 2013 22:17:01 GMT -5
The three most important ingredients in tumbling are patience, patience, patience. I also like to run 10 day charges to ensure all the grit has broken down & a good finish is achieved, it also helps in case some courser grit has snuck in. As others have said, the most important & tedious step is course grind. Every time I short this step I end up being disapointed.
Rich
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Jasper-hound
starting to spend too much on rocks
Member since June 2010
Posts: 208
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Post by Jasper-hound on Dec 15, 2013 11:37:52 GMT -5
I am known to run 60/90 for more than a month. I will "harvest" out rocks every couple weeks and add in new rough material to the barrel. When I am tired of running it all, I will do a wash up and shut down, setting aside the unfinished rocks until next time I am ready to fire up.
I know a lot of members on RTH follow this same procedure. Many people just leave a rotary running all the time, doing harvests every two or three weeks, and recharging with fresh grit.
There is even someone on here who just tumbles forever with 60/90, after which the grit is so broken down that the stones can go right to the prepolish or polish phase.
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