There is no way that I know of (30 years experience) to make the
crack disappear at this point. And the only way I know of to get the
epoxy into the crack and not all over the stone is to get it all
aver the stone then finish it off with a smooth 600 grit then Zam on
a muslin buff. This leaves the epoxy where you want it and not where
you don't. I do this type of repair for clients who want to keep the
stone for emotional reasons and don't mind the crack. I would
usually suggest removing the stone and cutting a new one.
Did you back the stone prior to setting with anything? I use
sawdust, this cushions the stone and evens out the back to provide a
flat surface. I have also used blotter paper and thin cardboard but
always go back to sawdust since I am faster at it that the others.
This means that the bezel has to be high enough to accommodate the
stone and the backing material but results in a high success rate.
Sam Patania, Tucson