Back to Ganoksin | FAQ | Contact

Cracked opal repair


#1

Hello,

I have someone in the Atlanta area who has an opal ring that has
slightly cracked; it is a family heirloom and she was wondering if
there were a way to repair it with a glue or resin before it chips
off. Can anyone here help? She’s not far from Atlanta; I’ll be glad
to pass a name on.

Thank you,
Donna-Cluny


#2

You can use opticon…slow heating of the piece with opticon on the
surface…let it sink in, add hardener, clean off. You can heat
opals enough to use opticon, you may even be able to do it while it’s
in the ring setting. I use the heat from my dop wax heater…which is
nothing more than a metal box with a 100 watt lightbulb.

jeanne


#3

I’ll add an “amen” to Jeanne’s suggestion of Opticon for repairing a
cracked opal. I’ve used it with great results. I’ve placed the stone
with the Opticon in a vacum chamber for a few seconds and then put it
under a warm light bulb for over night. Of course the treatment must
be disclosed.

Jo
www.timothywgreen.com


#4
I'll add an "amen" to Jeanne's suggestion of Opticon for repairing
a cracked opal. I've used it with great results. I've placed the
stone with the Opticon in a vacum chamber for a few seconds and
then put it under a warm light bulb for over night. Of course the
treatment must be disclosed. 

It should be mentioned, however, that opticon has it’s limits. One is
that it can only affect a fracture that reaches the surface. That
seems obvious, but sometimes people think a fracture does this, when
it does not. Also, opticon is applied first as a liquid resin, one
part of an epoxy based formula. The second part is usually applied
afterward. What this means is that the hardener cures the resin near
the surface, where it can reach. But it does not penetrate as deeply
as the original resin applicaion. That application does most of the
work to make the fracture less visible, of course, but those
portions of tht first application that are more than a trace below
the stone surface are not actually cured or hardened. That means
those areas do not act as an adhesive, only as an optical aid in
hiding the fracture. The importance of this is that the OP wished a
treatment to not only heal the fracture visually, but physically as
well, so the cracked part of flake would not come off. Opticon is
only marginally of use in this, because only the surface resin is
cured and therefor acting as a glue. The uncured resin might be a bit
gummy after a while, but doesn’t offer much in real adhesion.

Another product that may be worth trying is a cyanoacrylate based
glue. Sold for gluing glass together, it works well at being
virtually invisible when on materials with refractive indexes close
to glass. The stuff I’ve got in mind (no specific brand, there are
several available) is cured by ultraviolet light, so it only works
with materials that will allow UV to penetrate. Ordinary super glue
probably isn’t such a good choice, because it cures so quickly that
it would be hard to get decent penetration of the fracture. But the
UV curing stuff can be applied in darkened or UV free location
(indoor incandescent subdued lighting), and vacuumed, gently warmed,
or otherwise given time and encouragement to penetrate the fracture.
it’s formulated with a very low viscosity, and the few times I’ve
used it, seems to penetrate well into tiny fissures. When satisfied
with the appearance, one then exposes it to UV radiation (UV lamp, or
just good sunlight). Since this can cure all the way into the
material (assumeing the material is not opaque to UV), then it’s
ability to physically adhere the fracture together is pretty good.
How it compares to opticons ability to fill a fracture visually, I
don’t know, but as a glue, I suspect it might be stronger.

Hope that helps.
Peter Rowe


#5
I've placed the stone with the Opticon in a vacum chamber for a
few seconds and then put it under a warm light bulb for over
night. 

Is the overnight incubation before or after applying hardener?

Thanks
Noel


#6

Noel- I put the hardener on after the overnight under the lamp. After
I apply the hardener I give the stone a good wipe down with lint free
cloth or tissue paper and then place it back under the lamp for about
30 min.-

jo
www.timothywgreen.com


#7

Where would I find Opticon?


#8
Where would I find Opticon? 

I would think any lapidary supply place like Graves etc and I know
I’ve seen it on Ebay.

Jeanne


#9

Coit. For opticon, go to gravescompany.com. They usually have it.

But before doing that, let me give you another possible technique.

Because of the viscosity of Opticon, when repairing a stone with
very small cracks or pits etc, I use the following.

Mix some 2 part Epoxy (use Hughes 220 as it dries crystal clear and
sets quickly- also available from Graves Co.). Slowly mix the Epoxy
into acetone until it becomes not quite as thin as water but
certainly thinner than cream. Warm the stone to dispell any internal
air. Notice I said warm…opal hates heat. Now immerse the stone in
the mixture and let it set for about an hour. Take it out and put it
under a 60 watt bulb. That will cure the Epoxy more quickly. This
gives much deeper penetration into the cracks and fizzures if,
indeed, it can be penetrated. Have had wonderful result with Hondorus
black opal, dino bone and many others.

Sometimes a piece will hang together for awhile, but generally, such
repairs are temporary at best.

Good Luck. Cheers fromn Don at The Charles Belle


#10
Where would I find Opticon? 

Many Rock Shops and Lapidary suppliers sell Opticon 224 Fracture
Sealer

The manufacturer of Opticon 224 Fracture Sealer is:

Hughes Associates
18116 Minnetonka Blvd
Wayzata, MN 55391
Phone: 952-404-2626
Fax: 952-474-4636

They Only sell wholesale lots - their smallest parcel is 6 - 9 0z
units

Note: they also manufacture the: "2 part Epoxy (use Hughes 220)"
suggested by Don at The Charles Belle on a Google search we found the
following:

Irons Lapidary sells singe units of

Opticon 224 Fracture Sealer
http://www.lapidarysupplies.net/glues.htm

They also sell the Epoxy 220 or 330 Adhesive Cement

Standard Disclaimer: No commercial relationship with any of the
above

Best regards,
Robert P. Lowe Jr.
Lowe Associates - Brasil