Advice with crack/fracture repair Options

[GuitarC]

Just attended 2nd class of a "Beginning Cabochon" course I am taking and I am learning a lot . I was working on the CabKing 280 wheel doming my 30-40mm oval jasper cab and class was ending so dried off stone and checked a small inclusion I was keeping my eye on and it is now a thin fracture line . It starts at the edge and runs almost parallel to the edge of the stone 2-3mm in from the edge before ending at the edge an inch away from where it starts. It looks like that piece could completely crack off the stone if I continue to work it and the cab still needs some doming before moving on to 600 etc. I told the instructor and asked her if a 2 part epoxy could be used and then continue shaping/polishing etc and she said I could try that next week or I could pick another slab next week and start over. Starting over is no big deal because I know I can get back to where I am in one class. I have already decided that I am going start a new cab next week.

I might make a smaller piece from this cracked cab, maybe a guitar pick!


I have 2 questions:

1. If I choose to make a guitar pick and trim it down to guitar pick size (cutting off the fractured portion), I need to thin the piece since it is thin for a cabochon but too thick to be a guitar pick even for me. I like thicker picks 2-3mm range but the cab is now 5mm. Do I thin it on a flat lap or some other method?

2. I probably will not attempt to repair the fracture but want to know the best ways to repair cracks and fractures because I am sure I will encounter them in the future. I have not worked with stone prior to last week but think a few methods of repair could work. I would think that heating a stone opens a fracture and would also further liquify an epoxy upon contact and allow it to fully seep in. Is heating a stone to repair it this way a good idea? What type of epoxy is good for use on stone? Another method is to fully submerge the piece in heated liquid plastic to let it fill a crack or fracture. These are just theories based on working with other materials so I do not know how well they would work on stone. Any advice, tips, experiences?

Thanks!

[GuitarC]

Had my 3rd Beginning Cab class yesterday and I was able to do what I planned this week. I got a new rough slab since the cab I worked on the first 2 classes has a decent sized fracture that I did not want to mess with now. It's a piece of brazilian agate that's thicker than my first cab and has some nice colorings of blue, gray and green. I drew out my shape then trimmed it on a trim saw and used a 100 grit wheel and with about 30 minutes of grinding so far, things moved much quicker since I know a little more the 2nd time around. I put a chamfer on after putting on a good angle for the bezel to grab and then dopped it and grinded between the girdle and my drawn guidelines to create a few terraces using a 100 grit wheel. It's nothing pretty yet and my Palm Pre camera does not show details up close but the basic shape and hazed color can at least be seen.