goldfinger1
starting to spend too much on rocks
Member since November 2008
Posts: 154
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Post by goldfinger1 on Jul 26, 2021 8:15:19 GMT -5
Hello Everyone
I purchased 3 unpolished slabs in the 5"X 2" range. I'd like to either have someone polish them for me or perhaps I could polish them by hand without any lapidary equipment. Absolutely no sense buying equipment for just 3 slabs.
Has anyone had experience polishing by hand? Can it be done with good results? If so, what materials do you recommend?
Thanks in advance.
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JR8675309
freely admits to licking rocks
Member since August 2019
Posts: 807
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Post by JR8675309 on Jul 26, 2021 8:40:33 GMT -5
I've polished thunderers with my orbital and normal velcro backed sanding disks (wet the rock, sand, wet the rock, sand rinse and repeat. Of course, that's just one side you have to do, I'm guessing you would want to do edges as well and I think that would be hard w/an orbital. Just my 2 cents.
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Post by HankRocks on Jul 26, 2021 8:59:21 GMT -5
goldfinger1Polishing by hand would be a daunting, time consuming task. Not a route I would choose. Your best bet in my opinion would a Flat Vib Lap. I do have one and I keep it running year round mostly polishing geodes/ Pet Wood and a few end cuts that are too large to tumble. The problem with slabs, and with un-balanced pieces is that they need weight added. I caulk lead weights to the pieces to either add weight or to provide balance for even grinding/polishing. I allow a week or more for the caulk to dry. The thicker slabs are better as they tend to not have the caulk continually contacted by the slurry in the pan which can cause the caulk to release. There is also the cleaning and rinsing between each stage, more effort. This is a bit too much info for you, however just trying to point out the work involved in Vib Lap polishing. These factors are probably why no one has volunteered to do this for you. In addition to the time involved, shipping the rocks twice would add to your cost. Plus any complication with breakage and whose fault, etc, etc.... I have polished(and cut) a few selected pieces for friends now and then. No pressure and no money, just a favor. Do you have a Gem and Mineral Club close to your location. A lot(not all) can be helpful and they have equipment.
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on Jul 26, 2021 9:29:14 GMT -5
I have done it by hand and it is a tiring process. I have done it entirely by hand using wet sandpaper on a smooth backer and it is not something I would like to do frequently.
The easier way to do it is using diamond polishing pads with an orbital sander/polisher. That method is not too bad and is what I have done several times face-polishing coprolites. I try to do several at a time so I can work on the same pad longer without changing. I dip the rock in water frequently and don’t move to the next higher grit until I am pleased with the way it looks. I made the mistake of rushing it once and having to go back 5 steps to fix a scratch is not fun.
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jul 26, 2021 11:16:10 GMT -5
When I was in grad school I did several slabs by hand with grit 120, 220, 400, 600 on a flat glass plate while watching Sunday football. I takes lots of time but it can be done. Just join a rock club and use their shop. Meet some great people and learn so much. If you have real good material someone may do it for you in return for some of the material.
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Post by greig on Jul 26, 2021 11:25:48 GMT -5
I have done it by hand and it is a tiring process. I have done it entirely by hand using wet sandpaper on a smooth backer and it is not something I would like to do frequently. The easier way to do it is using diamond polishing pads with an orbital sander/polisher. That method is not too bad and is what I have done several times face-polishing coprolites. I try to do several at a time so I can work on the same pad longer without changing. I dip the rock in water frequently and don’t move to the next higher grit until I am pleased with the way it looks. I made the mistake of rushing it once and having to go back 5 steps to fix a scratch is not fun. Good point. You don't notice the imperfections until later grits and the only solution is to go back a few grits to correct.
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goldfinger1
starting to spend too much on rocks
Member since November 2008
Posts: 154
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Post by goldfinger1 on Jul 26, 2021 12:05:24 GMT -5
I'm wondering if I could just coat the slabs with some type of epoxy which would leave a glossy shine.. This way I might be able to eliminate the sanding and polishing aspect.
Does anyone think that might work and be better? These are just slabs for display and not going to be cut into cabochons.
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Post by Peruano on Jul 26, 2021 13:12:58 GMT -5
coating with epoxy would work (unless it turned yellow), but no it would not be better (unless better is defined as easier).
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Post by parfive on Jul 26, 2021 13:13:25 GMT -5
Epoxy = blasphemy around here. : ) Give this a shot just for the hell of it . . . sprinkle some polish on a piece of denim or any old rag for that matter and give one of those slabs a good rub for a minute. You might spiff it up enough for the back of a shelf in a dark corner.
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jul 26, 2021 15:20:41 GMT -5
Please do not spray them with a clear coat you will never be happy with the results and you will make it harder to have them polished in the future. Put them in a jar of water to display till you find someone to polish them for you. Where are you at maybe someone near you can help you out.
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goldfinger1
starting to spend too much on rocks
Member since November 2008
Posts: 154
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Post by goldfinger1 on Jul 26, 2021 16:18:36 GMT -5
goldfinger1Polishing by hand would be a daunting, time consuming task. Not a route I would choose. Your best bet in my opinion would a Flat Vib Lap. I do have one and I keep it running year round mostly polishing geodes/ Pet Wood and a few end cuts that are too large to tumble. The problem with slabs, and with un-balanced pieces is that they need weight added. I caulk lead weights to the pieces to either add weight or to provide balance for even grinding/polishing. I allow a week or more for the caulk to dry. The thicker slabs are better as they tend to not have the caulk continually contacted by the slurry in the pan which can cause the caulk to release. There is also the cleaning and rinsing between each stage, more effort. This is a bit too much info for you, however just trying to point out the work involved in Vib Lap polishing. These factors are probably why no one has volunteered to do this for you. In addition to the time involved, shipping the rocks twice would add to your cost. Plus any complication with breakage and whose fault, etc, etc.... I have polished(and cut) a few selected pieces for friends now and then. No pressure and no money, just a favor. Do you have a Gem and Mineral Club close to your location. A lot(not all) can be helpful and they have equipment. I'm sure there's a gem and mineral club or two in my area but don't know anyone. I'm retired and don't drive anymore as I readily fall asleep from my prescription medications. I have a lot of time on my hands and am never afraid to work at something as long as I like the results. This is one project I might like. I'm going to order some grits and diamond powder and try my hand at manual polishing. I don't think they could turn out worse no matter what I did.😉
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Post by parfive on Jul 26, 2021 20:03:44 GMT -5
Three unpolished slabs, six faces.
First suggestion – pick the very best face for your first attempt. Saw marks are a royal pain to remove by hand and it takes a fair amount of elbow grease for every thousandth on the road to flat enough to polish.
When it’s time for your first re-charge—arm or grit—clean and dry the slab and hold it up to a light. You’ll easily see how true the slab is and what’s left to deal with.
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goldfinger1
starting to spend too much on rocks
Member since November 2008
Posts: 154
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Post by goldfinger1 on Jul 27, 2021 7:40:35 GMT -5
What is the minimum sized grit required to get a mirror polish on agates?
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Post by hummingbirdstones on Jul 27, 2021 10:32:25 GMT -5
What is the minimum sized grit required to get a mirror polish on agates? Here is a good discussion of polishing slabs by hand on Ganoskin using either a piece of glass and silicon carbide grit or using SIC sandpaper. It may give you some ideas.
Getting a mirror polish on a slab by hand is going to be difficult, but I would say you need to take the slab up to 14,000 diamond and then finish polishing with cerium oxide or aluminum oxide. If you have a buff (like a car polishing buff) that would fit into a hand drill, that would be the best way to get the best polish you can on your slabs with CeOx or AlOx.
His Glass Works also has a video up on lapping glass. I'm giving you this link just so you can see the technique used if you go with the glass/SIC grit scenario. The lapping technique would be the same.
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goldfinger1
starting to spend too much on rocks
Member since November 2008
Posts: 154
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Post by goldfinger1 on Jul 27, 2021 16:06:01 GMT -5
I'm wondering if I could just coat the slabs with some type of epoxy which would leave a glossy shine.. This way I might be able to eliminate the sanding and polishing aspect. Does anyone think that might work and be better? These are just slabs for display and not going to be cut into cabochons. It looks like the epoxy route is going to be the best, easiest and cheapest way to get a suitable mirror finish on my slabs. I've talked to a number of people they recommend a product called HXTAL. It's A two part epoxy that doesn't yellow over time. If I'm not satisfied I can always start over again and try the long, manual polishing method.
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brotherbill
spending too much on rocks
Member since October 2018
Posts: 382
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Post by brotherbill on Jul 27, 2021 16:44:48 GMT -5
If you decide to go down the epoxy road you might want to consider Art Resin. It is more economical than Hxtal, cures faster and is generally way easier to use. Fencejumper started a thread recently promoting it as a stabilizer so I gave it a try to stabilize some dino bone and was blown away by the finish after it hardened.
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goldfinger1
starting to spend too much on rocks
Member since November 2008
Posts: 154
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Post by goldfinger1 on Jul 27, 2021 20:56:22 GMT -5
If you decide to go down the epoxy road you might want to consider Art Resin. It is more economical than Hxtal, cures faster and is generally way easier to use. Fencejumper started a thread recently promoting it as a stabilizer so I gave it a try to stabilize some dino bone and was blown away by the finish after it hardened. I wish I could find that thread.
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Post by hummingbirdstones on Jul 27, 2021 21:27:45 GMT -5
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jul 27, 2021 23:20:13 GMT -5
goldfinger1 Before you spend a dime on putting plastic on slabs that are probable millions of years old lets make sure we know what we are dealing with. This is a lapidary forum we can do better then to tell you to spray them with clear plastic.
What type of material are the slabs? Rock type and /or lapidary name? How much did you pay for them and where did you get them. Do you know where the material is from or who you got it from. As you can not get out to get help from a local rock club I will have our Southern California club polish them for you. We have several Lapidary artists ( I am only a geologist) and a full shop with the latest diamond equipment. I have learned so much from this group over the years that I have used to keep our shop and equipment in top shape it is time to pay it back. Send me a message or give me an email and we will set it up. You can ship the slabs in a small flat rate box and I will have one of the members polish them and mail them back to you. We will not have the shop back open until September 1 and it should only take a few weeks after that depending on what the material is.
Save the rocks! No dyes no plastic
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Post by tims on Aug 2, 2021 4:29:27 GMT -5
I've done a 5"x3" end cut (1 side) by hand using tumbling grit on a piece of glass. It took approx 30 hours, but at least half that time was just getting it past the 1st stage ... as mentioned saw marks are a pain. It's the first stone i cut and first i polished, and i'll treasure it until i die.
I know a guy that just rubs oil on his rocks to make them shine. Epoxy might give you good results. Whatever floats your boat.
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