Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,484
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Post by Sabre52 on Jun 10, 2013 21:06:11 GMT -5
Howdy folks,
Seems funny to me to admit this, but in fifty years of cabbing, I've only cut one obsidian cab. After seeing Randy and Krystee's incredible rainbow obsidian cabs, I've got the bug to try and cut me one for my collection. Roy sent me a great looking hunk of rainbow but I don't want to mess that one up so I've been trying to cut some crappy Mexican Rainbow I got years ago from the E-Bay gal who used to always flaunt her cleavage in her sales adds. I didn't mind the flashing but God they sent me high priced crappy obsidian with lots of flaws and bubbles. *L*. Anyway, I tried to cut the first piece today and found I haven't a clue how to get the flash.
The stuff, though flawed, shows fantastic electric flash in the conchoidal fractures at an angle to the layering. Tried to cut it at a slight angle and no flash, just kind of banding. it does show some flash if I move it all around though. next, I tried to cut it parallel to the banding an danged if it didn't come out looking just the same. Now does the flash not show till I crown the cabs or what? Any help on properly orienting this junk would sure be appreciated....Mel
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Deleted
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Post by Deleted on Jun 10, 2013 21:12:22 GMT -5
Mel, I have been studying this for about a year. In that time I have successfully cut about 10# of flashy material.
The flash is oriented parallel to the bands. I haven't cabbed any, but seeing recent cabochons posted it seems the rounded nature of the cab allows for a little flexibility in the cut.
My rather limited and youthful advice is to cut a slab as I described and cab a portion to see.
========================further and perhaps more useful information===========================
someone said to stand outside with the sun behind you and wet the stone. Rotate it until "get the flash" and the slab on that plane.
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Post by paulshiroma on Jun 10, 2013 21:29:24 GMT -5
Scott helped me out with this ... at least, I think it was Scott. Anyway, I dunked the pieces in some water and then rotated them in bright, direct sunlight until I could see the color. I tagged that location with some painters tape and then used that as my starting point, cutting along that plane ... in other words, what Scott said LOL!
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Deleted
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Post by Deleted on Jun 10, 2013 21:46:09 GMT -5
Scott helped me out with this ... at least, I think it was Scott. Anyway, I dunked the pieces in some water and then rotated them in bright, direct sunlight until I could see the color. I tagged that location with some painters tape and then used that as my starting point, cutting along that plane ... in other words, what Scott said LOL! Yeah, what he said! I don't remember where I learned it.
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Post by paulshiroma on Jun 10, 2013 21:46:58 GMT -5
Why does it feel weird giving advice to Mel? That's like me correcting the folks who write for Wikipedia ... And I'm excited to see your work, Mel! Paul
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,484
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Post by Sabre52 on Jun 10, 2013 22:06:01 GMT -5
Dang, I cut a slab parallel to the banding and it didn't seem to show the flash that shows in the chipped areas. Going to have to look at it again in different light I guess. Thanks for the advice....Mel
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Deleted
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Post by Deleted on Jun 11, 2013 11:42:02 GMT -5
Dang, I cut a slab parallel to the banding and it didn't seem to show the flash that shows in the chipped areas. Going to have to look at it again in different light I guess. Thanks for the advice....Mel Make cuts parallel to the flash. But it's more than that. There isn't flash in every band. Put the sun behind you and have a new go at it. Yes, Paul it feels very weird to be in a position to help Mel. He is my guru for so many things. Feels good too. Paul, I will bet there are some topics you SHOULD be writing for at wikipedia. Tell me I am wrong.
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Post by Bikerrandy on Jun 11, 2013 14:19:55 GMT -5
I've been trying to cut some crappy Mexican Rainbow I got years ago from the E-Bay gal who used to always flaunt her cleavage in her sales adds. "Teresarocks", she did have a nice pair eh? lol.... I slab mine exactly like you mentioned, at a slight angle parallel to the bands. After you cut a slab, take a spray bottle with you and go out in the sunlight and get the slab wet. Rotate it until it flashes, and draw an arrow pointing up with a sharpy marker. This will be the top of your cab(s). The flash always shows up better when cabbed (unless there's no flash to begin with). If you haven't done so, I highly recommend ordering a large flat rater from Tony. At the price he's selling, it's the best deal on the internet!
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Tommy
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Post by Tommy on Jun 11, 2013 15:51:23 GMT -5
This is a timely thread so thank you Mel for starting it. I feel a bit like what Paul said – when Mel speaks I tend to shut up and listen.
At the rock sale I showed you guys pictures of a couple weeks ago they have a huge pile of obsidian all collected at Davis Creek – the old gal was trying to convince me to buy some. She pointed out all the banded pieces and said they were rainbow and that in order to achieve a perfect rainbow the cut needed to be performed at a 12% angle to the bands…She also went on to say that her husband had tried for 40 years and never successfully found it hahaha.
So anyway I’m trying to get back in there and this time I will pick up a few pieces to try. I feel a lot better knowing that it’s not as easy as it seems :-)
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Don
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He wants you too, Malachi.
Member since December 2009
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Post by Don on Jun 11, 2013 16:19:46 GMT -5
There are two theories on cutting this stuff; first is to cut parallel to the layers. the second is to cut 15 degrees off parallel. 15 degrees off parallel will give you bands of colors across the slab.
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Deleted
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Post by Deleted on Jun 11, 2013 19:55:04 GMT -5
"Teresarocks", she did have a nice pair eh? lol.... Wowzers!! Nice specimens!! sorry Mel, OT, but I couldn't resist!
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Post by Bikerrandy on Jun 11, 2013 20:15:30 GMT -5
Yep, somehow they end up in every one of her pics. lol
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Post by frane on Jun 12, 2013 7:32:54 GMT -5
Mel,
One thing I haven't done yet and think I should try is something that I learned a long time ago on here. Someone said that while they are looking at the best flash in the piece, they dip the bottom in a can of old paint. That gives them the best line for cutting. I really need to try that because I cut some about 7 degrees off the paralel because it worked for me not long ago but didn't seem to work this time...Time to try the paint trick.
Fran
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Post by bobby1 on Jun 13, 2013 0:28:09 GMT -5
You can dip the piece in water and use the water line as the orientation... Not quite as messy as paint. If you cut the material at an angle to the bands you do get the multiple colors but it is a very directional slab. You can only get the multiple colors in one orientation. Rotate it any direction off that plane and the color extinguishes. Its great for a color orientation if it worn as a pendant because it stays in only one orientation, right between Theresa's ......UM,UH I got distracted.. If you cut it exactly on the color plane and the color bands are narrow you can get the rainbow of colors by using a high dome. I cut the material in thicker slabs because you need the density of thicker material to prevent the slab/cab from allowing light to pass through the piece thus dimming the colors. A lot of the bands in the material can be rather thick. Cut parallel to the band, 1/2" thick and with the slab wet look closely for minute parallel color lines. Cut a high domed very narrow (1/2") wide 1-1/2" long cab with these lines perpendicular to the long dimension (lines going across the narrow dimension). You will get a catseye cab. Check out the June 2010 Lapidary Journal and you can read these instructions accompanied by photos (my article). Bob
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,484
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Post by Sabre52 on Jun 13, 2013 8:58:36 GMT -5
More great advice. Thanks everyone! Somehow, I think I'll not be able to tell how this is going until I actually get to cabbing..Seems like this is going to take some experimentation. Still have to cut a bunch more slabs so i can get some clear areas in this crappy obsidian to try to cab and it sounds like very thick slabs are in order so I'll take that under consideration. Again, thanks for all the great info....Mel
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Post by paulshiroma on Jun 14, 2013 20:44:10 GMT -5
This is a timely thread so thank you Mel for starting it. I feel a bit like what Paul said – when Mel speaks I tend to shut up and listen. At the rock sale I showed you guys pictures of a couple weeks ago they have a huge pile of obsidian all collected at Davis Creek – the old gal was trying to convince me to buy some. She pointed out all the banded pieces and said they were rainbow and that in order to achieve a perfect rainbow the cut needed to be performed at a 12% angle to the bands…She also went on to say that her husband had tried for 40 years and never successfully found it hahaha. So anyway I’m trying to get back in there and this time I will pick up a few pieces to try. I feel a lot better knowing that it’s not as easy as it seems :-) Hey Tommy - Yeah, I ended up examine, mark, slab, re-examine, re-mark if necessary, reposition, slab, repeat. Can be kind of a pain sometimes
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Post by tntmom on Jun 14, 2013 23:24:20 GMT -5
Bob's right (I learned almost everything about obsidian from him!). Thick cuts on rainbow or sheens. If it's too thin then the colors will be washed out. If you cut parallel to the band and manage to get a good flash, when you high dome it it will reveal additional bands as you get closer to the girdle, bulls eye effect (like Randy's fire gold sheen cab). Or, very narrow (teardrop or oval) cab with SUPER high dome for cat's eye. And here is a good link that Jason posted a long time ago on how to cut/slab it..... forum.rocktumblinghobby.com/thread/42517/proper-cutting-sheen-obsidians
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