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Removing epoxy from natural opal cab


#1

Hello there

Hope you’re well. I need some help please. I have a gold symbol
glued with good epoxy to an 18x13 natural opal cab and I need to
remove the gold symbol. What can I soak the cab in that won’t destroy
the opal please?

Thanks!!!
Jot Singh Khalsa
www.khalsakirpans.com


#2

There is nothing that will attack the epoxy that wont affect the
opal so your best bet is to carefully pare away the epoxy with a
razor blade or craft knife blade.

Nick


#3

Good Day!

If you are certain it is epoxy you can use “Attack” or strong paint
stripper. Both contain methylene chloride, which is toxic and should
be used with caution. You may need to soak it overnight. If the
adhesive is superglue (cyanoacrylate), acetone will work. Again use
all proper precautions, as acetone is flammable and toxic.

Neither will harm the opal.

Wayne Emery


#4

Hi

Soak the opal in acetone until the epoxy dissolves and the symbol
falls off, the opal should not be harmed.

Peter Taubers
www.andamookaopal.com


#5

Cured epoxy does not dissolve in acetone. I wouldnt put opal in
acetone for any length of time either as osmosis will cause
replacement of the water in the opal structure and leave the surface
looking white and possibly powdery. Australian opal is more
resilient than just about any other locality but I would only ever
use acetone for wiping residues of dop wax etc from it, not soaking a
stone in it.

Nick


#6

I’ve used Attack with opal in metal frequently with no untoward
results. If another material, say leather, is involved I don’t know.

KPK


#7

Hi Nick,

While I am not an opal specialist, I am a professional cutter. I
handle opal maybe once a week on average (most of my work is custom
faceting and repair to the trade). I’m in my 32nd year of this. I
passed the 1000 piece mark with opal long ago.

Apparently, your experience is somehow different, but I have NEVER
seen an opal damaged by soaking in a solvent, unless that opal has
been filled with an epoxy like Opticon to “heal” the cracks.

I HAVE seen opal break when a 2-part epoxy (not a cyanoacrylate) is
is used to glue an opal to a small dop in preparation for working on
the stone. The shrinkage of the excess epoxy around the dop pulls on
the unsupported opal hard enough to fracture it, but only if the
epoxy is allowed to cure for an extended period. Amber and other
softer materials are prone to the same thing.

For this reason, cyanoacrylate (SuperGlue) is a preferred adhesive
for opal, and acetone will break the bond with no damage to the
opal. Often, freezing will as well, but a quick return from the
freezer to room temperature is scary with larger opal. I don’t
really recommend it with someone else’s opal.

Would you please give us an example of a solvent damaging an opal,
and why that could take place? This is not about me being right and
you being wrong (I think you are), but about disseminating
that may be misleading to those who are in earlier parts
of their journey here.

Oh, I’ve been wrong before, but…

Wayne Emery


#8

Hello Wayne, For the most part I agree with you wholeheartedly. I
don’t believe the opal in the situation that caused this thread is in
any jeopardy from the solvent suggestions, however this is not always
the case. When epoxy is subjected to a solvent it expands and if the
opal is held by the jewellery item in a manner that restricts the
movement of the stone during that expansion, it will crack the opal.I
do considerably more opal inlay than I ever wanted to and have
repaired countless pieces. Soaking a multi-inlayed piece in Acetone
or Attack in order to replace the damaged sections will often destroy
the undamaged sections as the epoxy expands unevenly.Also triplets
that are separating rarely survive this treatment as the epoxy almost
never releases evenly. Doublets will fare better but I would never
guarantee the success. I do know that NO natural opal I have soaked
in solvent has been changed in any way or been damaged by such
treatment other than the mechanical damage mentioned. This includes
Sugar opal, Boulder opal, Yahweh nuts, Hydrophane and catseye opal.
There is a lot of rubbish and nonsense believed about opal porosity
and water content in spite of the Australian government’s Dept of
Mines pamphlets and myth dispelling publications.

Tony.Anthony Lloyd-Rees.
www.OpalsInTheBag.com


#9
When epoxy is subjected to a solvent it expands and if the opal is
held by the jewellery item in a manner that restricts the movement
of the stone during that expansion, it will crack the opal. 

I’ve been using opal in inlay and other forms of mountings and never
heard of this happening. Not being a chemist I don’t know what
happens to epoxy at a micro-level. But on a practical level my
experience tells me it doesn’t make any difference.

On the other hand, I’ve heard so many tales of opal I can only
conjecture that some people, not you Tony, of course, use poor
quality opal which results in strange events.

KPK