richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jul 20, 2016 11:23:13 GMT -5
jdubs, I agree, I need to buy 50lb of 30 SiC. I wonder if anyone can offer a vendor who has good quality material at a good price?
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jul 20, 2016 11:11:12 GMT -5
I have been keeping a journal for my rock tumbler with information like what kind of rocks are in the barrel, what time and date it was started, how much grit was put in, how much water, media… I find it has been helpful in my learning process though I seem to be a slow learner. I have been doing this since February and still no shiny rocks. I do think I am starting to make progress and definitely think keeping the journal (as well as reading the posts on this forum) are keys to my improvement.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jul 20, 2016 10:57:16 GMT -5
Victor1941, yes as I understand it you are correct that the gabbro is composed of two materials. I am definitely limited on my knowledge of geology but I believe gabbro is usually a pyroxene that is usually pretty soft like 5 or 6 and feldspar that is hardness of around 6. It seems like there isn’t a huge difference between the base materials. However, from what I have been told gabbro refers to a pretty wide range of rocks so I don’t really know what I am dealing with. The material I am trying to tumble/polish was sold under the name “indigo gabbro” and was purchased from a seller on amazon.com.
I believe this material can be polished and I very much would like to polish mine. I appreciate that it might not be the easiest material to polish but I do have a strong desire to get the job done. I guess what I am looking for here is any tips from those experience polishing softer materials. My rocks are getting smaller and smaller as I keep trying to redo them and I hope I can get some shiny rocks before they are reduced to a pile of dust.
All: As an update, I ended up trying some jasper and agate in the Harbor Freight vibratory tumbler. It has published capacity of 5lbs. I used the following in the vib:
3lbs small ceramic media 1.5lbs of agates and jasper that had completed stage one (smooth surface with minimal cracks and chips…) 4tbsp of ALO 70 grit (black colored material purchased from Harbor Freight) ½ cup of sugar And water added (~1/3 cup) until the rocks were covered with moist grit and were rolling around in the vib at a rate that approximated what I saw in youtube videos showing how a vib tumbler should look when properly loaded.
I checked the rocks every two hours and added water to keep things running the way they seemed they should. After six hours I noticed that the nut that holds the lid on was starting to back out allowing the lid to loosen and for water/grit to start to splatter out of the tumbler. I spent some time getting everything running smoothly again and tried to get the lid on tight so it wouldn’t come open again. After one hour I noticed that the nut had worked its way loose again. Again I tried cleaning up everything and get the lid as secure as I could. The tumbler was started again and when I checked it in half an hour I checked on it and found that the lid had come completely off and slurry had sprayed all over the work area.
I am not sure what exactly went wrong. The vib tumbler was not “walking” around, it stayed exactly where I had placed it. I guessed that the loading might be too much so I took half a pound of rocks out along with half a pound of media making the total loading of the vib tumbler 3.5lbs of rocks/media. I also tried to make sure none of the rocks were particularly large. All of the rocks range from ½ to 1 inch in size.
This time I started it up and stayed with the vib tumbler keeping an eye on things. After a few minutes I saw that the nut was starting to turn again and re-tightened it. Again after a few more minutes it had worked its way loose.
At that point I decided it was time to seek help. I’m starting to think that a vibratory tumbler might be a bit too advanced for me at this time.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jul 19, 2016 8:28:31 GMT -5
I am still working on my agates in my rotary tumbler and the anticipation is driving me crazy. I have been checking them every three or four days and adding more coarse grit. It seems like after 3 days 90% of the grit has broken down to a fine powder and after 4 days there are no coarse grains left at all. I have been rinsing everything out and adding fresh coarse grit and things seem to be progressing nicely.
Before I started my agates I had been working on some gabbro and had the coarse stage (30-90 grit then 120-220 grit) complete and the rocks were looking and feeling silky smooth with no pits or cracks that I could see. Had moved to 500 grit and after three days I checked on the rocks to see how they were doing and to my disappointment I found that they were heavily pitted.
My formula was 1lb of rocks, 1lb of small ceramic media (non-abrasive), 2tbsp 500grit ALO and water up to the top of the rocks/media. I tried to be very careful not to overfill the barrel and when I rotated it in my hand it sounded like everything was moving nicely.
I then started again with the 120-220 grit and got them smooth again. This time I purchased a vibratory tumbler from Harbor Freight and placed the rocks inside in the following formula.
~1lb of gabbro ~3lb ceramic media 2 tbsp 500 grit ALO
Then I turned on the machine and added water until I could see everything was moving and coated with a thin film of ALO slurry. I let this run for 12 hours and once again I found that everything was pitted.
Any suggestions? My hope was that the vibratory tumbler would be gentler on the rocks but that doesn’t seem to be the case. Other than reduced cycle time, is there any advantage to a vibratory tumbler over a rotary tumbler? I must say that the vibratory tumbler makes a lot more noise than my little Harbor Freight rotary tumbler.
Thanks
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jul 10, 2016 23:02:28 GMT -5
Some very nice looking rocks. The finish looks a lot like what I have gotten so far. I'm trying hard to get them glossier. Keep up the good work, I love looking at these photos.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jun 30, 2016 20:07:06 GMT -5
Garage Rocker,
The grit pack that I purchased was from Tru-square Metal Products. It was from thumlerstumbler.com packs 310 “Coarse Grit” 311 “Fine Grit” 312 “Prepolish” and 313 “Polish” I also got a bag of 320 “Plastic Tumbling Beads”
They don’t give a whole lot of information about it and I just assumed they were appropriate for a high-gloss polish. However, from looking at photos posted in the photos section of this site I haven’t been able to achieve anywhere near the level of shine that others are getting. I have taken some of my better looking rocks and have started them through the process again. As was pointed out previously I don’t think I gave enough time in the first stage and wonder if that might have limited what I could achieve in the following stages.
jamesp
I definitely want to go back down to the river but it looks like it will be a while before I get another chance to. We have had some pretty serious flooding and the river has been extremely high for weeks. I am itching to get back and find some more jasper.
I am sure I rushed the first two stages. It totally makes sense. I think these rocks will look really beautiful with all those crevices and scratches worn away.
Thanks very much for the tumbling recipes, I am giving it a try.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jun 28, 2016 18:15:57 GMT -5
Thanks for all the great information, that is exactly what I was looking for. I did buy a four part grit kit and that is what I have been using. I will try to get some 500 grit and some actual polish and see how things go.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jun 27, 2016 19:32:12 GMT -5
Thanks to everyone who replied. I was on a family vacation and am just now able to read them.
One quick update, I had been working on some of what I believe to be jasper that I found in a river bank and the results seem much more promising. The rocks started out pretty rounded already so that probably helped. I tried tumbling nothing but the jasper and checked them when I got home and they actually look shiny! Not quite as shiny as I hoped but much better than anything I have seen so far.
A couple of additional questions I have are about washing off the excess polish. I believe I am using Aluminum Oxide polish and it looks like everything has a thin film of the polish on it. I tried tumbling for a couple of hours with a tablespoon of borax and that helped but there is still lots of residue in the crevices so I started over again with a tablespoon of borax but I also added a cut up paper towel. I will see how they look in the morning.
I also have a question about the different stages of tumbling. I have watched several youtube videos and advice seems to be all over the place. Someone please correct me but here is what I understand the various stages to be.
Coarse stage: Smoothes out the rough edges and gets the rocks to the proper rounded shape. This stage should be run until all of the major grooves and edges are worn away. At the end of this stage the rocks should have pretty much their final shape. I find that I get best results when I add an additional tablespoon of grit every third day. So far I have been using SiC 46-70 grit and it seems to work fairly well but seems somewhat expensive. I spoke to a geologist and he suggested using aluminum oxide as an alternative but I don’t really know where to buy it.
Fine stage: Cleans up any residual scratches and blemishes left over from the coarse stage. So far I find that my rocks come out very smooth by the end of this stage. There have been a couple of times that I almost wanted to go directly to the polishing stage from here. I have been using SiC 120-220 grit for this stage so far.
Pre-polish Stage: Not really sure what this does. The rocks don’t seem to look much/any different at the end of this stage than they did at the end of the fine grit stage. What I have seen on a few occasions so far is that the rocks have come out rougher after this stage than they were going in. I suspect that the problem might be that I have a mixture of rocks with varying hardness and the harder rocks are damaging the softer ones. I have been trying to match the hardness of my rocks in each batch but this has been quite a challenge so far.
Polish Stage: Gives the shine to the rocks. My biggest challenge here seems to be getting the excess polish off of the rocks.
I have a couple of questions about the “thickness” of my slurry. The various tutorials that I have read and watched all seem to suggest adding three or four tablespoons of grit or polish to the tumbler with 3lbs of rocks resulting in a tumbler that is around 2/3 to 3/4 full. To this water is added until it reaches the level of the top of the rocks after they have been shaken down to their lowest level in the tumbler. The resulting slurry is very thin/watery. From reading some of the posts here it sounds like it is desirable to have a thicker slurry to maximize the contact between the grit and the rocks. If this is true, how does one achieve a thicker slurry? What should the slurry look like going into each stage?
In addition I am very curious to know what the rocks should look like at the end of each stage. How do I know when a stage is completed and the rocks are ready to advance to the next stage?
I have been making an effort to clean out the barrel at the end of each stage before starting the next stage. To do this I have been rinsing the barrel and rocks as best I can and then tumbling them for an hour with water and a tablespoon of borax then rinsing the barrel and rocks again. When I run my fingers over the barrel’s inner surface I can’t feel any grit and visually I can’t seen any grit or discoloration, however, the barrel is black rubber so it would probably be difficult to see contamination anyway. I suspect this might indeed be part of my problem.
From reading the responses I am probably ending the first stage too early. I noticed when I tried to tumble quartz rocks it did take a very long time before I could really see them smooth out. I have also tried some softer rocks and they seem to break down and in some cases totally disintegrate within a week.
With the softer rocks I have tried using plastic beads to keep them from tearing up too bad but I haven’t quite figured out the proper loading for them. The softer rocks seem to never really smooth out. Instead they seem to get pitted as I go and I just wear them down to tiny pebbles without ever getting the smooth surface I am after. Any advice for softer rocks is very much appreciated.
For those tumbling in the rotary tumbler (I also have a Harbor Freight style 3# tumbler) do you add extra grit when doing the first stage for 3+ weeks? When I check the tumbler I see that after a few days the grit that I put in seems to be broken down into much finer particles. With the finer particle size the rate of smoothing seems to slow drastically. Is this normal?
The suggestion about polishing jasper/agate was a very good one. I happened to stumble on that one myself and it definitely gave me my best results to date.
Thanks again for the help, my excitement is once again kindled.
Richard
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Jun 21, 2016 17:11:16 GMT -5
I’m new to tumbling, got a tumbler for my birthday earlier this year. I have done a few batches and am getting a little discouraged as the results haven’t been quite what I had hoped for. I received a mixed bag of rocks from Madagascar that I tried and it seems like all of the softer rocks were basically destroyed/ruined. I tried separating them by hardness but my skill at doing so appears to need plenty of improvement. I posted some of my results here: s1097.photobucket.com/user/RichardRocks1/library/?view=recent&page=1I wonder if the rocks I am using are simply not suitable for tumbling? None of my rocks have come out of the process looking all that shiny. Even the best ones look a little dull. I tried putting plastic beads in with what I believe are the softer rocks and sent them through the entire process again and still got the same results. I am using a 3lb tumbler and have been working in four stages. #1 ~3lbs of rocks with 3tbsp of 60-90 grit SiC #2 ~2.5lb of rocks (what was left from stage 1) with 3 tbsp of 120-220 grit SiC #3 ~2.5lb of rocks with 3tbsp “prepolish” #4 ~2.5lb of rocks with 3tbsp “polish” The grit was purchased as “set” from amazon.com Each stage was typically run from 5-7days Any suggestions are appreciated. Richard
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