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Post by perkins17 on Dec 11, 2021 22:48:26 GMT -5
I got a obsidian teardrop cab domed but was having trouble after the 400. I had scratches and flat spots. I went from a 600 nova to a 800 sic belt and was shaving issues with flat spots and scratches after that. Any suggestions? I got frustrated and quit for the night. Thank you in advance.
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Post by holajonathan on Dec 12, 2021 12:41:40 GMT -5
Frustration with cabbing obsidian... you and everyone else.  I've never had much luck with the stuff, and I've tried a number of times. Many suggest using old / heavily worn wheels to prevent scratches. Few of us have a complete set of old wheels lying around, and changing a bunch of wheels is a pain. Even if you manage to get it well domed and free of scratches using diamond and SiC wheels / belts, you will never get a good polish on it without some sort of buffing wheel or disc, together with cerium oxide or very fine grade aluminum oxide polish. Cerium seems to work best. Obsidian simply does not polish with diamonds, best I can tell, and it is not easy to polish no matter how you go about it. I don't mean to be negative about your cab. I'm just offering a dose of cold reality based on personal experience. Hopefully someone else chimes in with more helpful advice. |
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Post by hummingbirdstones on Dec 12, 2021 12:49:43 GMT -5
What grit did you start cabbing with? Obsidian is glass. If you started with 80 grit or some such you most likely have a great deal of subsurface damage that you will have to grind out before the scratches go away. Like holajonathan said, you will need an oxide polish as your last step (cerium preferably). |
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Post by holajonathan on Dec 12, 2021 13:04:30 GMT -5
What grit did you start cabbing with? Obsidian is glass. If you started with 80 grit or some such you most likely have a great deal of subsurface damage that you will have to grind out before the scratches go away. Like holajonathan said, you will need an oxide polish as your last step (cerium preferably). I agree. Stay away from the 80 grit hard wheel with obsidian. Best to start with a worn 220 wheel if you've got one. I've never used SiC belts, but I suspect they would cause less subsurface damage than diamonds. Might be best best to dome with a 220ish grit SiC belt. Obsidian is pretty soft, so it shouldn't be hard to dome with something other than diamonds. If you already used a coarse grit hard diamond wheel, I would give up on the cab before trying to grind out all of the subsurface damage. Obsidian is usually pretty cheap, and you'll spend a long time trying to fix an obsidian cab that has a bunch of subsurface fractures (they look like scratches, but don't disappear when sanding). |
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Post by perkins17 on Dec 12, 2021 13:50:21 GMT -5
Frustration with cabbing obsidian... you and everyone else. I've never had much luck with the stuff, and I've tried a number of times. Many suggest using old / heavily worn wheels to prevent scratches. Few of us have a complete set of old wheels lying around, and changing a bunch of wheels is a pain. Even if you manage to get it well domed and free of scratches using diamond and SiC wheels / belts, you will never get a good polish on it without some sort of buffing wheel or disc, together with cerium oxide or very fine grade aluminum oxide polish. Cerium seems to work best. Obsidian simply does not polish with diamonds, best I can tell, and it is not easy to polish no matter how you go about it. I don't mean to be negative about your cab. I'm just offering a dose of cold reality based on personal experience. Hopefully someone else chimes in with more helpful advice. Thank you for the advice. I have a cerium belt that barely fits on but works. You are not being negative. It's actually very helpful. |
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Post by perkins17 on Dec 12, 2021 13:52:12 GMT -5
What grit did you start cabbing with? Obsidian is glass. If you started with 80 grit or some such you most likely have a great deal of subsurface damage that you will have to grind out before the scratches go away. Like holajonathan said, you will need an oxide polish as your last step (cerium preferably). Shoot. I started with a hard 80 🙄. Maybe I'll go back to 220 and get it fixed up. Thank you for the advice. |
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Post by perkins17 on Dec 12, 2021 13:55:21 GMT -5
What grit did you start cabbing with? Obsidian is glass. If you started with 80 grit or some such you most likely have a great deal of subsurface damage that you will have to grind out before the scratches go away. Like holajonathan said, you will need an oxide polish as your last step (cerium preferably). I agree. Stay away from the 80 grit hard wheel with obsidian. Best to start with a worn 220 wheel if you've got one. I've never used SiC belts, but I suspect they would cause less subsurface damage than diamonds. Might be best best to dome with a 220ish grit SiC belt. Obsidian is pretty soft, so it shouldn't be hard to dome with something other than diamonds. If you already used a coarse grit hard diamond wheel, I would give up on the cab before trying to grind out all of the subsurface damage. Obsidian is usually pretty cheap, and you'll spend a long time trying to fix an obsidian cab that has a bunch of subsurface fractures (they look like scratches, but don't disappear when sanding). Dang it! Maybe I'll bring it back to 220. Mine is some gold sheen obsidian. I might work on it to see if I can get it fixed. It probably isn't worth it like you said though. Thank you for helping me out. |
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Post by holajonathan on Dec 12, 2021 14:03:40 GMT -5
I agree. Stay away from the 80 grit hard wheel with obsidian. Best to start with a worn 220 wheel if you've got one. I've never used SiC belts, but I suspect they would cause less subsurface damage than diamonds. Might be best best to dome with a 220ish grit SiC belt. Obsidian is pretty soft, so it shouldn't be hard to dome with something other than diamonds. If you already used a coarse grit hard diamond wheel, I would give up on the cab before trying to grind out all of the subsurface damage. Obsidian is usually pretty cheap, and you'll spend a long time trying to fix an obsidian cab that has a bunch of subsurface fractures (they look like scratches, but don't disappear when sanding). Dang it! Maybe I'll bring it back to 220. Mine is some gold sheen obsidian. I might work on it to see if I can get it fixed. It probably isn't worth it like you said though. Thank you for helping me out. It's worth a try. I don't know how deep the damage might be. Just don't be surprised if what look like scratches don't disappear as you sand them. When happened to me I felt like I was going crazy. I would sand, sand, sand, and while the stone was still wet, it looked like the "scratches" were gone. As soon as I dried the stone, the scratches were still there! That is how you know they are little fractures (subsurface damage) and not true scratches. And that is the point when I give up. |
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Post by perkins17 on Dec 12, 2021 14:07:22 GMT -5
Dang it! Maybe I'll bring it back to 220. Mine is some gold sheen obsidian. I might work on it to see if I can get it fixed. It probably isn't worth it like you said though. Thank you for helping me out. It's worth a try. I don't know how deep the damage might be. Just don't be surprised if what look like scratches don't disappear as you sand them. When happened to me I felt like I was going crazy. I would sand, sand, sand, and while the stone was still wet, it looked like the "scratches" were gone. As soon as I dried the stone, the scratches were still there! That is how you know they are little fractures (subsurface damage) and not true scratches. And that is the point when I give up. You described my experience exactly. I've got an 80 belt that I can take it back to. maybe I'll get it out. I've already invested a lot of time so it can't hurt to spend some more time on it. |
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Post by hummingbirdstones on Dec 12, 2021 15:57:18 GMT -5
I've shared this article before, but I think it's worthwhile to post it again. It was written for facetors, but the principle applies to every stone no matter how it is cut: Fine Cabinet Makers Don't Use Chain Saws |
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Post by MsAli on Dec 12, 2021 18:49:38 GMT -5
I absolutely love obsidian and there are others here better than I am at it. It is possible to get those scratches out. I know because I've done it SIC works better on obsidian when worn a tad. If they are new, do some agates on em 1st. Then, if you want to salvage it. Go back down to 220. Be soft and gentle with it. You may have to spend some time there, but patience is key. The rest of your steps are ok, but it really requires a light touch. Check it in between steps when it is dry and preferably with good light. I like polishing with AO 1st and the CO Hope that helps. jasperfanatic is really really good at obsidian. Maybe he will chime in |
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Post by perkins17 on Dec 12, 2021 19:18:06 GMT -5
I absolutely love obsidian and there are others here better than I am at it. It is possible to get those scratches out. I know because I've done it SIC works better on obsidian when worn a tad. If they are new, do some agates on em 1st. Then, if you want to salvage it. Go back down to 220. Be soft and gentle with it. You may have to spend some time there, but patience is key. The rest of your steps are ok, but it really requires a light touch. Check it in between steps when it is dry and preferably with good light. I like polishing with AO 1st and the CO Hope that helps. jasperfanatic is really really good at obsidian. Maybe he will chime in My belts are super worn. I will run back through that for sure! I have an AO 1200 belt that I use before final polishing and a CO belt that doesn't fit perfect. I truly appreciate the help, thank you! |
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