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 Post subject: more help please, with dopping, solvents, and polishing
PostPosted: Mon Aug 10, 2020 2:38 pm 
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Hi Gemology online forum members

I am back again for more of your expertise. I got done cutting a rose quartz stone and put it in acetone to remove it from the dop. I used 5 min epoxy, which I have been using for all my stones on the pavilion to cut the crown. So I put it in the acetone, and sort of forgot about it, and the acetone in the jar dried up. The stone came off the dop, but now is covered with a sticky white residue. I tried soaking it again in acetone a few days but it did not seem to do much. So yesterday, I placed it in a jar with some "attack" to see if it would come off. I checked the stone today, and it looks pretty much the same.

Now, I have very little knowledge of these epoxies and solvents. The "attack" I used had been sitting out in my garage for a while and there was just a small bit left. I think it must of evaporated slowly out of the container. I am wondering if the "active ingredient" has evaporated out, leaving it less effective, or if the "attack" is simply not going to do the trick. Is there something else I might use?

Since I am posting this question, I might as well ask another. I have cut a couple zircons, peridots, an apatite, and a topaz just now, and have noticed a difficulty with the cleavage. Mainly, at my prepolish stage, the facets near the cleavage plane are really rough looking, and then take a very long time to polish. I also end up having deep scratches appearing sporadically on polish and prepolish, which I feel like I just have to cross my fingers that I can get them out and that they won't appear again. But anyway, it takes me forever and then I overcut my meets. I have been using lightning lap products and the delite laps; I am wondering if the batt laps many of you use would leave a better finish with less problems, or if there is some trick to working with these stones with cleavages.

Thank you for your help!


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 Post subject: Re: more help please, with dopping, solvents, and polishing
PostPosted: Mon Aug 10, 2020 2:41 pm 
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A few days seems like a long time. Maybe epoxy is significantly different than CA, but it takes about 5 minutes of soaking my gems in a shot glass of acetone to cleanly break them off of the dops. I drop the gem back into the shot glass for another 5 minutes to weaken the integrity of any CA residue, and then just easily wipe it off with a paper towel.

Again - maybe epoxy is different, but the acetone works really fast with CA.


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 Post subject: Re: more help please, with dopping, solvents, and polishing
PostPosted: Mon Aug 10, 2020 3:16 pm 
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Location: San Marcos, CA
Are you stating that the residue epoxy after soaking will not wipe off with a acetone dampened paper towel? Or are you just waiting for it to disappear?

I have never had issues of cleavage on Zircon or Peridot. Careful with heat on these may alter color. I assume your issues with these is just cutting and polishing. Peridot you might have hit a section of a common inclusion in peridot a fingerprint(lily pad) and it is now exposed.

Apatite is a soft stone and requires a more delicate touch when cutting and polishing, Will scratch easily, but again I never had issues with cleavage.

Topaz does have a distinct cleavage plane and if one of your facets is on it, your not polishing that layer but removing very microscopic thin sheets, leaving and looking like ripples.

Yes Attack will evaporate quite quickly after opening and leaves a blueish purple residual behind. I too have tried to use, but it is ineffective.

I do not use epoxies but some CA in cases and stop using the Attack and just use acetone when needed.

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 Post subject: Re: more help please, with dopping, solvents, and polishing
PostPosted: Mon Aug 10, 2020 4:15 pm 
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The problem is I left the stone in the acetone, the acetone evaporated, and now the stone is covered with a sticky white film, that did not come off when soaking with clean acetone.

I like the epoxy for the transfer dop because it form fits around the pavilion better, and I do not have to use wax / torch/ shellac. The epoxy takes much longer to remove than the superglue. It doesn't really dissolve much, rather it just sort of loses its grip. So some part of the epoxy I have been using has apparently dissolved into the acetone (I have been using the same jar for a while, changing the acetone every now and then but there is some residue in it) and redeposited itself on my stone, but is not particularly fast to redissolve.

I have not tried to mechanically scrape off the residue; just trying to rub it off with my fingers did not do anything. It is sticky, and kind of smears around, unlike the usual bits of epoxy that come off clean.


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 Post subject: Re: more help please, with dopping, solvents, and polishing
PostPosted: Mon Aug 10, 2020 5:28 pm 
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If your positive it is quartz, you can try on low flame bringing it to a slow boil or just before in a pot of water. Not to leave it in to long maybe a minute or two. But bring the water to a boil with the stone in it, don't drop the stone into a boiling pot of water to much initial shock. Be careful handling the hot stone, maybe try the below first.
The other thing you can try is put it in the freezer and see if you can take like a popsicle stick or something like that and flake it off. Odd that the new acetone didn't solidify the epoxy. But I'm no chemist by any means. There are a couple people on the boards here that are maybe they see this post and chime in.

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 Post subject: Re: more help please, with dopping, solvents, and polishing
PostPosted: Tue Aug 11, 2020 1:05 pm 
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what about heating the dop (not the stone). The epxy will get soft and the stone comes off. Soaking the stone in epoxy afterwards will clean it. Use a glass with cover toavoid evaporaton. Ok that does not help on the actual stone.

If polishing gives scratches have you tried to change the polishing direction ?

Martin


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 Post subject: Re: more help please, with dopping, solvents, and polishing
PostPosted: Tue Aug 11, 2020 1:11 pm 
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capcuadrate wrote:
what about heating the dop (not the stone). The epxy will get soft and the stone comes off. Soaking the stone in epoxy afterwards will clean it. Use a glass with cover toavoid evaporaton. Ok that does not help on the actual stone.

If polishing gives scratches have you tried to change the polishing direction ?

Martin

He already has the dop released, he says that the epoxy will not come off the stone.

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 Post subject: Re: more help please, with dopping, solvents, and polishing
PostPosted: Sat Aug 15, 2020 10:08 pm 
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Update : I left the stone in the "attack" a couple more days and it did take the residue off.


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