When I am working single stones and am in a bit of hurry I use an Epoxy called UHU Creativ (Available at most Michaels-craft stores in the jewelry section - its marked good for glass, ceramic and jewelry).
It can be mixed for 60 seconds and you have almost exactly 3.5 minutes of working time, in the next 30 seconds it sets up and a the 5 minute mark it's all done as far as movement is concerned. It actually continues to get harder for about 24 hours - but you can put the saw to it within 10 minutes in most cases. After he 5 minutes I usually heat it under an incandescent bulb for another 5 minutes and then continue with whatever process I am working on.
I use Epoxy 330 when I need extra clear of if I need longer working time, it lasts about 15-20 minutes. It's good for heating the bubbles out under an incandescent light when making doublets or triplets.
Here are a couple more I did at the class I taught this last week. The first pair were a test to see how well the students could do 2 different hardness materials side by side, another used up scrap material, one was a first attempt at a curved internal frame using the natural shape of 6" Genie wheel, the last show the starting glue up and a "1/2" finish.
A stone with both a hard and soft material side by side - a little test of cutting two different materials and maintaining an even look ... sonora sunrise - black jade
So what do you do with small cut-offs and scraps - glue them up together and form a multi-part composite
Finally when I had a little time to experiment, I tried to use the 6" Genie wheel shape to make a rounded frame and cut a center to match. THis stone domes on both sides. Not bad for a first try!
One more 1/2 done cab to show them how to maintain a high dome without destroying it. Keep the bulls-eye on top until all else is done!
