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Faceting with Epoxy


#1

Recently had an explosive reaction when Tsavorite went into some Methylene Chloride to remove Epoxy! Anyone know about this??


#2

I think this is pretty unusual, because tsavorite is not known for being under strain or unstable and has no ready cleavage. It’s possible that there was some uneven strain when some of the epoxy released while other parts of it hung on. I have heard of cullets chipping off when releasing epoxy.

This doesn’t help you with that disaster, but such things are why I now only use a hybrid dopping method with an impression made in warm wax and then the stone glued to the impression with CA glue. Release can be with a warm knife or by hearing the dop or by dissolving in alcohol. If you only warm the wax enough to soften it to make the impression and release by dissolving in alcohol, the stone never gets very warm. I read about releasing epoxy in the oven or in the freezer, ditto for wax in the freezer, etc.,etc. All of these methods work with most stones which are not heat sensitive, but there is always the possibility of a problem with that one atypical stone, so my thinking is, why risk it? With an emerald I probably wouldn’t even use the hybrid dopping procedure and would use cold dopping with Elmer’s glue. That’s just my take on dopping, HTH, royjohn


#3

Thanks for the response.
Yea, I’ve never had this happen before (& don’t want it again!).
When I started opening the bottle after the stone dropped off, it was hissing & Bubbling/Boiling! It Even continued for several seconds after the Lid was off. This Attack (MC) is nasty stuff. I typically use CA for the Flat then need something stronger for the Pav or it will come off when I remove the Flat. Wax was so much safer, just not reliable. I only cut 1 stone at a time and if it falls off during final polishing, I’m ticked. I suppose I should test Acetone for > day to see if it will remove the epoxy.


#4

Well, as Paul Harvey used to say on the radio, “Now you know the rest of the story…” Yes, the heat could easily have fractured the stone, coming so quickly as it probably did with the chemical reaction. As far as wax dopping is concerned, it works well if the wax is quite liquid and the stone is at the same temperature as the wax to start. This is about 190*F for black faceting wax. Drop off is probably related to not a high enough dopping temp for the wax and/or the stone. If you use a diluted solution of dopping wax, just a pea sized drop diluted in 2 oz of alcohol and paint the stone with that and let it dry first, the wax will adhere much better and even if the temp isn’t too high. The wax is in effect adhering to itself. But the hybrid method does away with almost all the heating…just press the stone into the slightly fluid wax and create a unique impression and then when the wax is cold, put some CA glue into the impression and push the stone back into its own impression until it “locks” in and the CA bonds (15 sec). Wait a little for the glue to cure and facet. With this setup, if the stone comes off, there will be a jagged hole and you can reattach by using CA glue again. Just apply and again fit the stone and the wax that is adhering to it back into the jagged “keyhole.”

But, yes, if you’re going to use epoxy, do investigate a less vigorous solvent to use. Many people just heat the other end of the dop until the heat reaches the epoxy enough for the stone to fall off. Since there is a thickness of epoxy adhering to the stone, not so much heat reaches it, so this method is fairly safe for stones that aren’t heat sensitive…HTH,
royjohn