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Post by Jack ( Yorkshire) on Jan 11, 2009 5:07:31 GMT -5
Hi
I bought some opal over a year ago, havent had the nerve to get started on it.
I have been busy setting up a Silversmithing course here
Any tips on orentation and cutting the right way, also the progression of grits to Dimond paste much appreciated
Also any books that would be helpfull or Web pages
Many thanks
Jack Yorkshire UK
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Jan 11, 2009 12:14:14 GMT -5
There is a video in the general section in the "rock video" sticky post about cutting opals. I'm not sure how good it really is but I knew where it was so....
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Post by Michael John on Jan 11, 2009 13:10:39 GMT -5
What KIND of opal?
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Jan 11, 2009 13:31:55 GMT -5
Michael John nailed the crux- different types of opal demand different approaches in cutting. Approaching a chunck of Spencer Idaho opal is a whole different game than a piece of Australian Koroit boulder opal, while Mexican or Oregon"jelly" "contra-luz" or "fire opal", are all similar but still different than any of the more classical Australian precious opal. All opals are easy to screw up, which is why nicely finished stones go for huge dollars, but also because most opal rough is so pricy, you want to kind of know what you are doing going into it. This is a good book; www.amazon.com/Opal-Cutting-Made-Jewelry-Crafts/dp/0962531146/ref=sr_1_2?ie=UTF8&s=books&qid=1231698067&sr=1-2but the Amazon pricing is way out of whack, for cryin' out loud- its only 100 friggin' pages folks! Check around rock shops and swap meets, you should be able to come across a copy for more like $30 or so. yes- still expensive but its a good resource that covers a lot of aspects and techniques. (Otherwise look for my copy on e-bay next week...)
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Post by Jack ( Yorkshire) on Jan 12, 2009 3:29:29 GMT -5
Hi All, Thanks for the info sorry I was a bit schetchy I got 1/2 Kg of white green blue from Lightening Ridge. heres a photo (Photoed DRY ) there is a lot more colour than this shows. I will have a look at the vidio tutorial and the Amozone book but Ebay would be better ? thanks. I also got a bit of Boulder opal but thats different (Filthy stuff) Jack Yorkshire Uk
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Post by Tweetiepy on Jan 12, 2009 11:20:38 GMT -5
You got the jackpot there! Do they have to be kept wet?
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Jan 12, 2009 11:46:08 GMT -5
1) Opal (precious) doesn't like heat so use lots of water, and a light touch.
2) Don't chase color, if you see it work around it.
3) Hold the Opal in the way it is going to be used (ie a pendant should show color best when looking very slightly down at it compared to straight on: rings should show best straight on unless it is a directional ring (can only be worn one way) then you can direct the color towards the wearer slightly).
4) When it's done...leave it alone.
5) If a problem shows up, don't go back to square one unless you absolutely have too. Remember, there wasn't that much color there when you started and there is even less half way thru.
Practice...Pick out the pieces with the least amount of color, orientate them and try to get the best stone you can out if it with the least amount of grinding.
I do Honduran Opal and use :
.012 & .006 blades on trim saw w/oil (not a tile saw)(thin blades are fragile and need some experience, but are a necessity when working with precious materials, and trim close so you don't wear out your wheels)
100 Diamond hard wheel
360 Diamond hard wheel
600 Diamond belt on expanding wheel
1200 Diamond belt on expanding wheel
3000 Diamond belt on expanding wheel
8000 Diamond belt on expanding wheel
14000 Diamond belt on expanding wheel
50000 Diamond belt on expanding wheel
Cerium Oxide on a damp felt pad (spray lightly with water when you feel the stone dragging).
All run @ 1750 rpm (I have the option of 1150 rpm but hardly ever use it).
I don't see the reason for over-working wheels, hence the closer ratio of wheels.
And I still believe a worn 600 belt is just a worn 600 belt, and not equivalent to a 1200 belt. ;D
Again this is what works for Honduran Opal (Crystal, Andesite, Black Seam, Black Matrix, Nodules).
Just remember, cutting Opal is very satisfying, BUT, it can break your heart too! (but don't take it personally).
Dr Joe
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Jan 12, 2009 11:49:42 GMT -5
You got the jackpot there! Do they have to be kept wet? Quality Opal does not have to be kept wet unless your storing it in a de-humidified area. Dr Joe .
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mirkaba
spending too much on rocks
Member since August 2006
Posts: 321
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Post by mirkaba on Jan 12, 2009 15:21:45 GMT -5
The white opal seems to be a little softer I start it on a 22 sc belt. The small stuff black or white I statrt on a 600 hard diamond wheel. Works for me........Bob
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Post by Jack ( Yorkshire) on Jan 13, 2009 4:04:42 GMT -5
Thanks Dr Joe ,
Brilliant this is just what I need to know both sides of the coin so to speak.
Bob Thanks also
Twety pie, I havent kept it wet as it wont be when its finished, I mentioned it when photoing it as when wet it shows colour a lot more , I was in a rush .
Saskrock I found some good advice and tutorial vidios on U Tube thanks
Thanks all again
Jack Yorkshire UK
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Post by Tony W on Jan 14, 2009 1:22:15 GMT -5
I'll take any of the dirty boulder opal you don't want For the boulder opal use lots of water and keep a sprayer on hand to clean the stone well. Wear an apron. Look often, light touch, look often, use finer grits the most, look often, very, very gentle on grit under 600, look often. A trick I use is to photograph my rough wet, in the sun, before I begin. The camera sees color, and pattern your eye may miss, and that can often help you orient the dome. Tony
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Post by Jack ( Yorkshire) on Jan 14, 2009 4:15:03 GMT -5
Thanks Tony Thats a help it is very dirty stuff though and I need that "light touch"
Jack Yorkshire UK
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Post by Jack ( Yorkshire) on Jan 17, 2009 15:40:54 GMT -5
Excelent Tutorial Vidios on you tube,
on Opal Cutting ,Silversmithing , and Jewellery making in fact most aspects of the Jewellery trade
Thanks for the info again
I will have a go at cutting when this RH hand of mine heals up and the Silversmithing course I run ,( terms 2 & 3) come to a end.
Jack Yorkshire uk
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