transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 19, 2014 15:16:59 GMT -5
sorry, put this in the wrong spot. Ok so I made a pendant, it's not quite a cab more like a face polished slablet but think I can get my question answered here better than elsewhere in the forum. I have cerium oxide for final polish. Says 1 micron which is about 14,000 grit size, but I'm not getting the desired finish. Is it the stone? Is it the grit? What do you use for final polish? Here's what my shine looks like: Without shine: Taking suggestions. This is being done by hand. Started with 120 grit, then 500 grit, then 1200 grit silicon carbide wet/dry sandpaper. Polish is being done on a piece of leather.
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Post by rockjunquie on Aug 19, 2014 15:31:20 GMT -5
Is that dino bone? It would help to know what kind of stone your working on to know what kind of polish it might take.
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transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 19, 2014 15:43:20 GMT -5
Yes it is... whoops forgot to mention that.
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transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 19, 2014 15:50:03 GMT -5
If I was to guess at what's going on ....the area between the cells is undercutting, the area inside the cells is similar in hardness to what's between the cells and what's being undercut is scratching the surface inside the cells. I've been at this for several days now (about an hour a day). Improvements in finish have plateaued.
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Post by stardiamond on Aug 19, 2014 15:58:33 GMT -5
I learned to polish using tin oxide and I hated the undercutting. I only use diamond; 3000, 14,000 Nova and then 50,000 100,000 canvas pad with diamond paste.
The other cause of not getting a shine is poorer material.
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transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 19, 2014 16:09:56 GMT -5
Yeah I'm also wondering if it's too porous. Second pic bottom left you can see some light colored spots inside the cells. This was low end of prices I found on ebay so my expectations of it weren't all that high.
Where do you get the 50,000?
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Post by rockjunquie on Aug 19, 2014 16:17:56 GMT -5
If I was to guess at what's going on ....the area between the cells is undercutting, the area inside the cells is similar in hardness to what's between the cells and what's being undercut is scratching the surface inside the cells. I've been at this for several days now (about an hour a day). Improvements in finish have plateaued. If I am reading this right... I don't think the matrix is cutting into the cells if it is softer (aka undercutting). It would have to be harder to scratch the cells. The cells are agatized. I assume you are using your hands to do this? Try using a stiff piece of something behind your sanding, that will help with undercutting. Try to keep all the grits and all the water that you used with those grits separate. You could be getting contamination which is scratching the red cells.
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Post by rockjunquie on Aug 19, 2014 16:23:39 GMT -5
You can buy diamond paste up to 100,000 grit. Bone should polish pretty good by 12,000.
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Post by stardiamond on Aug 19, 2014 16:42:18 GMT -5
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transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 19, 2014 16:42:53 GMT -5
I have been very careful to not cross contaminate, maybe the porosity looks like what I'm seeing as scratches, not sure I can't find my loupe.
Yes I've been using my hand (holding the bone and rubbing the leather against it) I'll give it another go with something stiff under the leather and see if that helps any. If not oh well, still awesome stuff even if it's not high quality. Just figured I should try my best to achieve a good shine before giving up on it.
Thanks for the advice
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transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 19, 2014 16:57:26 GMT -5
Bookmarked, thankyou. At one point I had requested a catalog from raytek I think it's called. They are located in my state a couple towns over but there was no pricing in the catalog and it wasnt necessary for what I was trying to do so I ended up getting the cerium oxide.
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transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 20, 2014 10:01:59 GMT -5
Thanks for tip rockjunquie, definitely some improvement in the undercutting issue. I really think the material is too porous to get a really high shine, but it's WAY better than how it was when I got it so I'm happy with it. Here's update on it
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Post by mohs on Aug 21, 2014 11:20:49 GMT -5
did you drill that hole? fine shine bone pendant
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transcendental
spending too much on rocks
Member since June 2014
Posts: 459
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Post by transcendental on Aug 21, 2014 13:17:02 GMT -5
Thanks, yes I did, took forever! Bone is hard stuff!
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