The Pulitzer Opal Technique
Ethiopian Shewa Province Opal Stabilization
The goal of treatment is to remove all of the water and replace it with epoxy resin.
You must use Hxtal Epoxy. It is the world’s best epoxy and dries crystal clear and is very strong. It is used by museums to restore artifacts and art work. HXTAL IS EXPENSIVE. If you do not use it, I don’t believe that you will be successful. In order to do this, you need to replace the water with something that mixes with water, but also mixes with epoxy resin. Acetone is that “something.”
1. Never let Shewa opal dry out or it will be ruined. Acetone is the fastest drying liquid at room temperature, so be very careful.
2. Take water soaked Shewa opal, wipe off the excess water and put the stones in 100% acetone.
3. After about 12 hours at room temperature, the water in the stones be fully mixed with acetone. The acetone is then NOT 100% any more.
4. Repeat this step 3-5 more times. Remember that the goal is to reduce the amount of water in the acetone. Epoxy does not mix with water.
5. The more acetone in the container, the lower the concentration of water, so use as much acetone as your container will allow.
6. Pour out acetone out and immediately pour the Hxtal resin in. Completely cover the stones, then add about an extra inch of resin on top.
7. Heat resin to 180° F for 3-6 days. For stones thicker than one inch (2.5 cm), as much as 7-10 days may be necessary.
a. I personally use a vacuum oven, but honestly, I do not believe that vacuum is not necessary.
8. Take out of oven and let cool to room temperature, preferably 65-70°F.
9. Pour out resin and wipe excess off of the stones
10. Paint thick layer of hardener on stones and place on flexible plastic sheeting (Epoxy will not adhere strongly to plastics). Zip lock plastic bags work fine.
11. Place stones in spot where they are in the 70°s for 4-6 days. The lower the temperature, the more slowly it will harden. For thick stones, I believe that a temperature of 60-65° F for up to 10-12 days may work better (I have not tested this).
12. You may wipe the excess hardener off, then place the stones in a place at 85-95° F for 3-4 days. Heating cures epoxy much faster than at room temperature
13. After curing, there will be excess hardener on the stones. It is best to wipe this off with cloth. Ethyl or Isopropyl alcohol (95-100%) may help remove the residual hardener. (Tested, but not proven.)
