haskins02
off to a rocking start
Member since August 2009
Posts: 4
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Post by haskins02 on Aug 10, 2009 11:00:33 GMT -5
I have 2 or 3 small (1 inch or so) naturally-smooth beach rocks that I would like to polish to a glass-like sheen without a rock tumbler. I read elsewhere that I can accomplish this by polishing them by hand using sand paper of different grit sizes, starting from course, then to the next less course, etc., finally ending up with “fine grit diamond-ingrained sandpaper.”
My question is: Will this process result in a glass-like sheen, since it seems like diamond-ingrained sandpaper would be too hard and scratch the surface? Or perhaps the last step of the polishing process should be to use super fine steel wool, or even a non-metallic cloth of some type in order to get that bright shiny look. I don’t know.
I would appreciate any advice on how I could accomplish this without a rock tumbler and with the least amount of hassle. (I also have a rotary Dremel, but I am not sure if using it would make the job easier, since I do not have any polishing attachments and I do not know which ones to buy anyway, should they even exist, that would result in the glass-like shine I desire.) Thanks!
Greg
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tomcloss
starting to spend too much on rocks
Member since October 2008
Posts: 158
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Post by tomcloss on Aug 10, 2009 12:05:06 GMT -5
I've hand polished petoskey stones using wet / dry sand paper (some know this as Emery cloth) Start with a rough grade and work your way down to a finer grade a little at time. The key is to get all the pits out before moving from your first rough grade to the finer grades. For the final polish I use a damp piece of felt with some polish (Aluminium Oxide or Tin oxide). Hope this helps
Tom
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Post by johnjsgems on Aug 10, 2009 12:46:55 GMT -5
Greg if you are in US best to try an auto supply or auto paint supply. They will have wet/dry sand paper to pretty fine grit. Use every grit available to finest and then polish as Tom said. If you have a swimming pool, you can polish using the diatomaceous earth for the filter if you don't have a polish compound.
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haskins02
off to a rocking start
Member since August 2009
Posts: 4
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Post by haskins02 on Aug 10, 2009 17:42:36 GMT -5
Thanks for the suggestions. Some follow-up questions, if you don't mind:
I don't have that kind of swimming pool media, so where would I buy (including any specific brands or types) Aluminum Oxide or Tin Oxide? Is one better than the other to get a bright mirror-like finish?
Instead of damp felt (I don't have any felt), would a damp soft cloth work as well for the last polish step?
Is there a reason why a wet/dry sandpaper (or emery cloth) is better than normal dry sandpaper? Do I need to keep it wet while I polish? Thanks again.
Greg
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lparker
fully equipped rock polisher
Still doing too much for being retired!
Member since March 2008
Posts: 1,202
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Post by lparker on Aug 10, 2009 19:49:58 GMT -5
Then again, after all the trouble buying and hand sanding..you're rocks might NOT be able to be polished. They might be too soft or have the wrong grain structure. To guarantee a polish on a rock, spray it with a couple coats of Krylon Clear acrylic.
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tomcloss
starting to spend too much on rocks
Member since October 2008
Posts: 158
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Post by tomcloss on Aug 10, 2009 21:24:13 GMT -5
The Emery coth is better because you want to keep the rocks damp to cut down on the dust. as for a soft cloth I've always used felt or leather for buffing. You can use a piece a felt which can be purchased from most frat stores. last time I bought a piece it was $0.10 for a 10 x 12 inch piece. You can buy the polish fromany rock shop. I don't know where to buy it since I use the same polish I use when tumbling.
Iparker does have a point some rocks just won't take a shine.
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Post by johnjsgems on Aug 10, 2009 21:31:21 GMT -5
And, really hard rocks that will polish easily won't be easy to work by hand.
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carloscinco
fully equipped rock polisher
Member since July 2008
Posts: 1,639
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Post by carloscinco on Aug 10, 2009 21:42:54 GMT -5
I've hand polished agates before. The polish looks more organic because it is not perfectly flat. Drip water on the stone or paper often to keep the mud washed off. Johnjsgems is right that auto body paint supply stores have the best paper for this. Stick with silicone carbide. Look for the plastic backed Japanese paper that is as fine as 2000 grit. Get a paper called Polishing paper at a place that sells machinist supplies. This will put the final finish on your stones. You'll be able to crack geodes with your fingers when you're done.
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Post by connrock on Aug 11, 2009 6:31:40 GMT -5
Beach rocks can be very deceptive.When you see them wet on the beach they look so pretty but in a lot of cases they are too soft to get the type of shine you're looking for.
I think the 1st thing you should do it to do a simple scratch test to determine the hardness of your rocks.
You can do this with a steel file or a VERY good knife. Just try to scratch each rock and if it doesn't scratch it will shine up very nice for you.
If it does scratch either spray it (as mentioned) or keep it in water.
The "scratch" MUST be an actual scratch and NOT just a white streak hat can be wiped off with your finger.
All that being said,To hand polish a hard rock is a tough task which is VERY time consuming not to mention the cost of the wet paper you'll need.
Why not consider sending you rocks out to be tumbled?
If your rocks DO NOT scratch with a file or knife I will GLADLY do them for you with NO cost to you. ;D
connrock
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haskins02
off to a rocking start
Member since August 2009
Posts: 4
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Post by haskins02 on Aug 11, 2009 16:34:10 GMT -5
Thanks for all the great advice. The reason I don't simply buy a tumbler is because I only have two rocks (perhaps really just one rock) about an inch in diameter that I want to polish up (without painting with an artificial coating) just to see if it can be done. It would be hard to justify buying a tumbler for one small rock.
Greg
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carloscinco
fully equipped rock polisher
Member since July 2008
Posts: 1,639
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Post by carloscinco on Aug 11, 2009 18:21:07 GMT -5
Tape the paper down with duct tape so it doesn't slide around. Keep it wet. 200 grit was the best place for me to start. You'll work about an hour before your fingers cramp up. Post the result!
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Aug 11, 2009 18:49:38 GMT -5
Thanks for all the great advice. The reason I don't simply buy a tumbler is because I only have two rocks (perhaps really just one rock) about an inch in diameter that I want to polish up (without painting with an artificial coating) just to see if it can be done. It would be hard to justify buying a tumbler for one small rock. Greg If you feel like giving up after 6 hours or so with the sandpaper (that is about how long I lasted at the hand polishing game) you can always mail your one or two rocks off to just about anyone on this board and have them tossed into a tumbler batch- might be faster to just do that.... |
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haskins02
off to a rocking start
Member since August 2009
Posts: 4
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Post by haskins02 on Aug 13, 2009 11:47:10 GMT -5
Thanks. I'll see how it goes. I realize what I plan to do is unconventional, but I look forward to the challenge. I already ordered the polishing papers.
Greg
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Post by Jack ( Yorkshire) on Aug 17, 2009 3:17:49 GMT -5
Hi Greg,
I have a friend up Scotland who dosent sleep to well he polishes Scotish Agates by hand but it is weeks of "Hours"
If your in UK I would pop it in the tumbler for you I did one for one of my silversmithing ladies in May of this year ,
I think it would be the quickest and most eficent way
Rocks have been polished for years by hand befor electricity came along ,
Polishing by hand is mentioned in a few books and use grits (rather than papers)and use inside of round objects to give more area coverage, especialy on beach rocks
Have a good day
Jack
Yorkshire uk
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RockyBlue
fully equipped rock polisher
Go U.K.
Member since June 2006
Posts: 1,719
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Post by RockyBlue on Aug 18, 2009 8:07:21 GMT -5
Hey Greg! What you want to do is a lot of work,The best place to get SC sandpaper is Supergrit.com and when you sand by hand don`t skip grades of sandpaper ti just makes more work,also put a few drops of Joy dish washing soap in your water it makes your sandpaper last longer and keeps the grit cleaner.Hope this helps!.........Rocky
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