ADAMAS GEMOLOGICAL LABORATORY publishes gemologically oriented software for the jewelry appraiser, jeweler, or student in gemology or mineralogy. The laboratory also provides technical consulting and jewelry appraisal services to the trade and the public and expert witness services to the legal profession.  
How To Build A Low Cost Gem Treatment Chamber
John Caro
Article Copyright 1998 By John Caro, Jewelry By Design, 7756 Gunston Place, Lorton VA, 22079
   Questions On Article To John Caro
Publisher's Note: Adamas Gemological Laboratory is proud to publish this article contributed by John Caro, outlining the build of a simple emerald treatment processing device. Construction of and use of this equipment should only be undertaken with the utmost care. Your and other's safety is YOUR PRIMARY CONCERN.  Adamas Gemological Laboratory makes no warranties and assumes no liability for the use or misuse of this device. It is published solely for the exchange and stimulation of ideas.

Below you will find pictures of the chamber I built from commonly available plumbing parts. Simple to make and to operate, this information is free for you to use. I ask only three things;

1. If you make changes that work better, please share it with me.

2. Please read the instructions on the resins or oils you will be using to be sure they are compatible with this technique and the materials in this device. This device has not been tested with every possible combination of physical factors, chemicals and materials you may decide to use. So, if somehow this doesn't work for you the way you expect or you end up damaging something, you are responsible for the way you use this device.

3. By using any information, which follows, you agree to hold me and/or the owner of this website blameless, not responsible for itís reliability or the use of the information.

     Picture of treatment chamber in vise (but not hooked up to vacuum hose)
Assembling the Gem Treatment Chamber

Shopping list:

Dielectric Union ½" Female IPS to ½"O.D. Copper Pipe (Brass )

½" Square Head Plug (Brass) This will create the pressure on the treatment liquid.

One Foot of ½" Copper Pipe

½" Copper Pipe Tee

Cold Water Stem 9B-3C or (any Brass water stem that has a washer seat that will fit closely inside of the ½" pipe) This will be the pressure stem.

½" to 1" Pipe Adapter (Brass, ADP)

1" Pipe Adapter (Brass, ADP) This will be the stone chamber

½" Pipe Adapter (Brass, ADP)

½" to 1/4" Bushing (Brass)

1/4" to 1/4" I.D. Hose Adapter (Brass, ADP or ¼" to whatever size your vacuum hose is)

Several feet of ¼ " I.D. Vacuum Hose ( or whatever fits on your Vacuum Pump and long enough to go from it to the table vise)

1 ¼" x 1 ¼" Brass sheet at least 18ga.( 1mm) and enough Hard Silver Solder to solder to a 1" Pipe Adapter This will form the end of the stone chamber.

Tin Solder ( sometimes called Silver solder) and Paste Flux

A roll of Plumbers Joint Tape (Teflon?)

Three ¼" Flat Washers (Rubber)



Assembly Schematic Showing Reference Locations
Here is a diagram of where everything goes

How to Put it Together

1.    Cut pipe joints from 1í2" copper pipe just long enough to join the parts, leaving the one that joins the Dielectric Union and the Tee a ¼" to a ½" longer.
 2.    Grind and polish smooth curved bevels on the inside of the ends of the copper pipe joints as shown in the diagram under Location #1. This is so that the washers can be pushed and pulled into and out of these joints, without the edges chewing them up.

 3.    Solder together the Tee, pipe joint and the Dielectric Union with plumbers solder. IMPORTANT : Start with the one on the Dielectric Union Location #2 ( as this has a plastic washer that will melt if done last)

 4.    File the threads on the Square Head Plug (Location #3) so that it will screw all the way closed. The more travel you get here; the more pressure will be put on the treatment fluid.

     Pressure is a good thing !! ( If any of you can figure out a easier way to accomplish this
     please let me know, as this is the most time consuming step) Leave the Square Head Plug
     turned all the way out.
 5.    Cut or grind off the flange lip (the lip that holds the faucet washer on the end) on the cold water stem (Pressure Stem) so that the larger flat washers will sit flat on the end of it. Use the screw from the handle side to secure the washers to the stem.

 6.    Slip the pipe joint that goes between the Tee and the ½" x 1" Adapter into place in the Tee. Mark where it stops inside of the Tee. Remove the pipe joint. Then slip the stem into the open end of the Tee, handle side first with the washers on the outside end it, so that it touchs the Square Head Plug, which you left in place turned all the way out . Mark the length from      the plug to where the pipe joint that goes between the Tee and the ½" x 1" Adapter will be.

7.    Measure the length that the Pressure Stem needs to be and cut the excess off the handle side of the stem and grind it down, so that it fits the plug nicely. It should be just long enough, to almost touch the pipe joint that goes between the Tee and the ½" x 1" Adapter as shown in location #4. This Gap will allow air to be pulled out of the stone chamber.

8.    Solder the plate onto the 1" Adapter with hard silver solder. Solder together the rest of the joints and related parts with plumbers solder, rinse in pickle to remove flux and clean thoroughly in ultrasonic cleaner and rinse. Shape the plate to fit the end of the stone chamber (1"Adapter).

9.    Put Teflon Tape on all the threads and do a trial assembly and vacuum pull. This tape will seal the chamber and should now hold a vacuum. IMPORTANT: use lots of tape on the Square Head Plug. With all the filing it will probably fit the thread loosely.

10.    Remove the Square Head Plug, the 1/4" to 1/4" I.D. Hose Adapter and the stone chamber. Then push the Pressure Stem into the Dielectric Union washer side first. Once inside use a screw driver to screw in the screw that holds the washers and expand them slightly.

 Typical Treatment Procedure

1.    Fill the Stone chamber with your Treatment liquid and stones to be treated. Thread the Square Head Plug and the stone chamber back into place.

2.    Fill the rest of the chamber with your Treatment liquid up to the top of the Tee, by pouring it into hole where the 1/4" to 1/4" I.D. Hose Adapter goes. Clamp the large nut of the Dielectric Union in your table vise and reinstall the 1/4" to 1/4" I.D. Hose Adapter . Tighten all the fittings on the chamber and hook up the vacuum line again.

3.    Turn on your vacuum and pull out all the air you can.

4.    Screw the Square Head Plug all the way in, thereby putting pressure on your liquid.

5.    Heat the chamber as directed by your treatment productís instructions.

6.    Allow to cool and pour the liquid back into itís container by removing the Square Head Plug.
7.    Remove stones and dry or otherwise follow treatment productís instructions.
Publishers Note: A very good description of emerald treatment procedures may be found on Ted Themelis's  Web Site

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