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Post by bobby1 on Oct 10, 2015 22:49:47 GMT -5
I just finished this one. It is 5" tall, a bit larger than usual. Bob
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Post by Pat on Oct 11, 2015 0:16:50 GMT -5
It's a beauty! Thanks.
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Post by orrum on Oct 11, 2015 3:43:07 GMT -5
Yowser wowser big baby!!!
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bsky4463
fully equipped rock polisher
Member since September 2013
Posts: 1,696
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Post by bsky4463 on Oct 11, 2015 7:36:14 GMT -5
Massive, awesome. Great capture in that one. Cheers
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,681
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Post by Fossilman on Oct 11, 2015 9:19:59 GMT -5
Beautiful and full of character....
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Post by snowmom on Oct 11, 2015 17:17:52 GMT -5
WOW!
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Post by captbob on Oct 11, 2015 22:20:57 GMT -5
Now THAT'S a cab! Very impressive.
I have all the equipment to make cabs, have had for years. But I have never made even one. No desire. What the heck would I do with them?
Seeing this gives me a new interest though. Display specimens that aren't the size of a quarter. Intriguing possibilities.
Is this piece the normal thickness of a standard cab or somewhat thicker? If normal thickness, do you have added concern with breakage when working on a piece this size? Any "tricks" to going big?
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iamnoone
having dreams about rocks
If it's not shiny, it's not finished
Member since October 2013
Posts: 69
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Post by iamnoone on Oct 11, 2015 22:39:06 GMT -5
Beautiful!
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adrian65
Cave Dweller
Arch to golden memories and to great friends.
Member since February 2007
Posts: 10,774
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Post by adrian65 on Oct 11, 2015 22:50:10 GMT -5
Beautiful!
Is there a sagenite pocket in it?
Adrian
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timloco
has rocks in the head
Member since April 2012
Posts: 545
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Post by timloco on Oct 11, 2015 22:50:46 GMT -5
gorgeous, and well photographed!
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Post by bobby1 on Oct 11, 2015 23:03:32 GMT -5
Capt Bob, Unfortunately many of the slabs that I make these very large cabs from are the standard thickness - about 3/16" - so I have to do more work to get a good dome on them. I only use flawless (no fractures) slabs to make them so I haven't had any failures in many years of making them. It does require a cab machine with at least 2" between the wheels. I use a dry sanding process when I sand them and I only use 3" wide silicon carbide belts. I use respiratory protection suitable for my personal respiratory health (perfect for my age) and I do not dry sand the edges of the dome or the girdle because there isn't a large enough mass to absorb the heat. Dry sanding goes quite fast because I don't have to stop sanding, dry the piece off and observe for grinding/sanding marks that remain.I can see them as I go. Another reason that dry sanding goes so fast is related to one of the characteristics of water. It acts as a lubricant thus the sanding belt tends to slide over the cab rather than digging in as it would do dry. In one of my upcoming columns in Rock and Gem magazine I have described my dry sanding process. Bob
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Post by captbob on Oct 12, 2015 9:09:22 GMT -5
Thank you for taking the time to explain this Bob. You did this dry from start to finish!?
Could you please post here when your article is on the news stands? I would very much like to read it.
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Post by bobby1 on Oct 12, 2015 10:17:11 GMT -5
Adrian, There is only a small crystalline pocket above and to the left of the sagenitic feature. Captbob, I have to write the articles three months in advance of when they get published so it will probably be out by December or January. I grind wet but when I'm finished with the grinding I go to a very well worn dry 80 grit belt. The belt is so well worn it has a shiny surface. I keep these dry to maintain the surface. If the cab is larger like this one I use a less worn belt to make the process go quicker. In the case of this cab I noticed that I had some contour problems so I wet sanded the contour down with a much newer 80 grit belt to quickly remove the material. I went back to the very well worn belt and sanded from the center out to the edges with a pulling action until all the grinding marks were out. This goes quickly because of the aggressive (but smooth) action of the dry process. The surface is surprisingly smooth after this sanding. I then go to a wet 220 grit to sand the girdle and the upper edge of the dome. I make all of my cabs with a 1/8" flat (but slightly tilted in ) bezel so they can be easily bezel set, though I don't expect that this size cab will ever be set that way. The sanding of the back of the cab is also done dry. It also goes very quickly if the saw has cut a fairly smooth surface. Bob
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icatz
spending too much on rocks
Member since October 2015
Posts: 453
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Post by icatz on Oct 19, 2015 13:31:54 GMT -5
What a stunning stone! Gorgeous.
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Tom
fully equipped rock polisher
My dad Tom suddenly passed away yesterday, Just wanted his "rock" family to know.
Member since January 2013
Posts: 1,557
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Post by Tom on Oct 30, 2015 18:19:00 GMT -5
super nice Bobby
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