Adhesive needed

I am using an epoxy glue to adhere an inlaid opal into a 14K gold
setting (ring). I mix well, let the glue set up a minimum of 24 hours.
I do use a tiny (1-2%) color additive especially formulated for
fibreglass or epoxy resin. The back of my stone is “painted” with ink
from a felt tip pen. I have tried spray enamels, also an epoxy based
paint and found them unwilling to hold to the stone. I rough the back
of the stone with 180 grit sandpaper before setting, also use a burr
on the metal to rough it with cross-hatching. Here is the problem: I
have found that some epoxies let go when confronted with common
houselhold solvents such as alchohal, or gasoline. Not that my
customers are dipping thier hands, but a daily splash with after-shave
has been seen to disolve the connection. This was the one we have
trusted “epoxy 330.” Another I tried has been found to be brittle and
to let loose when the band is struck from underneath. I feel there
must be something out there that the inlay people are using and happy
with? Can anybody point me to what it is and where it can be purchased?

One of my customers liked to wear her crystals into the shower–long,
hot showere with lots of lotions and potions. She kept losing the
crystals. Finally, I contacted the 3M and Devcon companies, since I
was using their products. What I was told was this: Some epoxies are
resistant to alcohol bases, some are resistant to water. Since I
needed both, it was suggested I use Epoxy 330 by 3M, or Liquid Steel
by Devcon. I had previously used both, but I needed a clear adhesive,
so I called 3M back, and we talked. It was explained to me the biggest
reason for failure was contamination, improper ratio of the two parts,
or too fast or incomplete cure time. I figured the thing I was
probably having problems with was either contamination or cure time.
So I followed the fellow’s suggestion of washing first with a good
surfactant (I use Ajax dish soap because it has no emollients),
followed by several scrubbings with rubbing alcohol on a paper towel
without softening agents (no emollients, coarse, cheap), using latex
gloves during the entire time, etc. Then she got her crystal, but I
told her she couldn’t wear it into the shower for 2 weeks. It worked,
and she’s had it for 5 years this time, as well as plenty of other
crystals, all of which are worn into the shower on a daily basis.
Begin by contacting 3M or Devcon and explain what’s happening so they
can give their recommendations.

The epoxies can be colored with Japan colors or analine dyes. Use the
analine dyes in powdered form, the type used by woodworkers, not the
Rit dyes, as they have mordants in them.

Hope it helps.

Have you tried Zap A Gap?

Susan Chastain

Katherine: You said:

 " One of my customers liked to wear her crystals into the
shower--long, hot showere with lots of lotions and potions. She kept
losing the crystals.............." 

What was she wearing into the shower? earrings or rings? And what
were you glueing the crystals into? Were they round like beads? or

Just curious.

Larry, The best epoxy for inlay that is avaiable in the US is the
330. The additioin of coloring though can cause a change in the way
the epoxy sets and how it holds up. I used to use lampblack to
blacken my epoxy for inlay, but it gave the inlayed stone a fine
black outline that I didn’t like. I am now using Nigrosine powder
(the color agent for India ink) mixed into Alcohol. I then do a
light paint of the back of the opal, but not the edges. The alcohol
evaporates quickly and leaves a thin film of the Nigrosine. You have
to be careful in handling the opal now as you can rub off some of the
black. Then set with clear 330.

The opal doublet cutters in Australia put me onto the Nigrosine. I
wasn’t able to find it locally so one of my Ausse friends brought me
up some on his last trip. A teaspoon of the powder should last you
about two lifetimes, it really goes a long way. My friend also
brought me a sample of UHU Plus epoxy from Germany. This is the
epoxy used in Australia. You can vary the hardness of this epoxy by
varying the mix of harder. I am quite pleased with it but there is
no distributor in the US, and I would have to purchase close to $600
worth if I buy it from the manufacture.

On the prep work, you have to get every think surgically clean. I
clean the opal in acetone and then a dip in alcohol then blow it dry.
NEVER use your fingers while working with the opal, only clean
tweezers. Paint on a thin film of the blacking and let it dry. On the
gold, I clean it good in the ultrasonic and then steam it. Really
steam it.

When I mix the epoxy, I use the little tablespoon size plastic cups
like you get Chinese takeout sauce in. They are cheep and its a mix
once and throw away. I use a round tooth pick as my mixing and
application tool. When you put the epoxy into the channel for the
inlay, rub it in. Make sure you have no air trapped and you have
thoroughly wetted the gold with the epoxy. Now with the tweezers,
lower the opal into the setting and press into place. Don’t do any
cleanup of excess epoxy until it has completely hardened. When you
are working the opal down to the gold, watch that you don’t build up
heat, especially during the polish. The epoxy will start to break
down with the heat causing a weak joint.


Single and double-terminated points, pendants and rings, some regular
hexagonal shape, some unusually faceted with engravings on the back.
She has lots of them–ghosts, landscapes, you name it.

   And what were you glueing the crystals into? 

Some standard pre-cast mounts, caps and fabricated types with just
tendrils made of wire holding the crystals, and open-backed bezel
mounts. Pre-cast mounts are notorious for not fitting well; so some
must be burred out, some must be built up and then burred to fit.

I once was crazy enough to buy a large lot of unusual crystals, and
I’m still trying to get them all set in mountings. Sometimes I just
work on crystals for several weeks, then a lot of them go into a local
shop. If you need help with trying to fit some of your crystals, feel
free to contact me off list.

Larry first off, it sounds as though it might be the ink from the
felt tip pen that is letting go when attacked by the various solvents
that you mention. I appreciate your desire to have a black backing,
but I don’t think that ink, which was, after all, deposited from a
solvent itself, is really suitable if you want to use adhesives.

The other point I’d make is that even fresh abrasive paper can leave
a deposit on materials that gives rise to a weak bond. In my case it
was rigid foam being bonded to brass plates that had been roughed up
on a linisher. The plates were to be gripped in a tensile testing
machine, but the glue kept letting go very early in the test, until we
started washing the brass with acetone after it came from the

Watch out for those hard knocks that you say fracture the epoxy …
they could damage the opal instead once you’ve got a good bond. Good


Katherine: Thanks for your explanation - you do have an unusual
collection of crystals. Is there anywhere one can see your work? From
the assortment of crystals you list, I would imagine your work was
very creative. I love crystals, I’ve just not set very many of them -
couple of small ones. Personally I think the lady is nuts - surely she
could take her jewelry off before showering! But c’est la vie.
Probably more people than we know do the same thing.

Thanks for the offer of help, and should I need it, I’ll certainly
avail myself of it.