Author Topic: Help needed cutting boulder opal please  (Read 193 times)


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Help needed cutting boulder opal please
« on: April 11, 2019, 07:31:45 AM »
Hi all!
This is my first post and have just joined so here goes!
My name is Lockie and I have been cutting opal for many years, but not boulder
I have the 6 wheels nova machine and dremels with the small pink, grey, orange etc small wheels and many extra bits
I also have boulder syringes with demand compounds ass colours I have never used and are about 15 years old
My question is about cutting boulder opal, how to tell the difference of matrix on the surface of colour or if its coming up through the stone.
I am having trouble with this stone and now am stuck!
In the photo you can see the patches of colour with matrix on top, well I think its on top. I cut down into it and I loose colour so i stop.
This is a very expensive way to go as every time I get it wrong it destroys the stone.
I also would like to ask about getting a hi lustre polish a surface when there is undulations stoping me from using the nova wheels, I have tried using the small pink silicon wheels that go with the dermel tool but can not get a hi end finish.
Thanks for reading and would love some help cutting this type of stone I will now will try and load a photo.
I have cut all types of opal ( just not boulder ) and have good experience cabbing if I can help with any question other members have.
Thanks again Lockie
« Last Edit: April 11, 2019, 08:57:37 AM by lockie5 »


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Re: Help needed cutting boulder opal please
« Reply #1 on: April 11, 2019, 08:59:05 AM »
Hi, Lockie I have a bit of experience and most boulder opal I have cut only has the opal for a couple of millimetres on the surface of the iron stone or host rock, what I usually do is slice off the opal layer with about 5mm of the host rock, I then shape it with my diamond wheels probably 400 and 600 grit.  I then use my dremel to even up the opal surface using a split mandrel with 400 wet and dry paper incerted and finally I use a tin oxide cloth wheel to polish the final stone.  This has worked for me, but I am only a novice been doing it for about ten years and there are a lot more experienced people on this sight than me, so they will have a different way of doing it to me.   The other thing I do is cut down to a seem, so if I see a line of opal through the host rock, I grind down the iron stone with a 240 grit diamond wheel until I hit the colour, then I work around the seem until I expose it. :)


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