By Dick Friesen
I started researching jade polishing several years ago when I took over our club shop. I could get a polish on jade, but trying to tell someone else how to do it didn't seem to work. What I found, when I started reading, was that most authors had the same problem I had: they could do it, but the ability to someone else was hard. The problem, it seems to me, is that most of the directions are technique-sensitive, and telling someone why one piece of jade needs more pressure than another isn't easy to explain in print. What I wanted to discover was some way of polishing jade that would work regardless of the quality of the stone.
I had better luck talking to other cutters about their methods than reading about it. Al Youngquist of "Jade and More" told me to try Myers' Rapid Polish on a wood lap. I found it worked better than anything else I had ever used.
At this point I set up a series of experiments to see what other things affected the polish. The most common advice in the books seems to be: "sand it dry on a worn 600 grit belt." I didn't have a used one so I used a new one. Using the belt wet produced essentially the same results as the diamond belt. But dry, the surface started to look like it was almost ready to polish. I also tried a new 400 grit belt. The difference between the 400 and 600 was visible but small.
My next step was to find a finer grit silicon carbide belt. Rio Grande carries 3M's 15 and 9 micron belts and is the only source of finer grit belts I have found. Use their "micron graded," not the "Trizact" belts. (The Trizact belt is designed not to load and won't work. ) If you are using a Diamond Pacific Genie or similar machine, sanding disks on a rubber backing pad work fine. I found a supply of 1200 grit Pressure Sensitive Adhesive (PSA)-backed 6 inch disks at RedHill Corporation. I have also used 1200 grit paper and glued it to a Crystalite Flexodisc. Dry sanding isn't speed-sensitive, but it helps to keep a pan of water handy. Dip the stone in it occasionally to keep the jade cool enough to stay on the dop stick.
What I did find is that a worn 600 grit belt is about the same as a new 1200 grit belt. I was able to follow a dry 400, 600, or 1200 grit belt with the Rapid Polish and get a good polish with little or no "orange peel" pitting. The added steps.did seem to improve the finish in some cases.
I think the sanding surface gets loaded by jade particles whose size is determined by the grit size. This surface then "burnishes" the jade cab's surface. I think that the surface of the burnished cab is harder than the un-burnished jade. This harder surface is then less subject to orange-peel. This difference in hardness, if real, is small. I believe thatthis surface change is what has led to some of the different jade polishing methods. If the time one spends on the polishing buff is short enough after the dry sanding, the jade is less sensitive to how it is polished. But if one leaves the jade on the buff long enough one may go through the hard surface and get down to orange-peel. The Rapid Polish never seemed to go through this hard surface- perhaps that's why it worked so well. Tin oxide will also work if one doesn't have Rapid Polish. I don't recommend diamond for a final sanding or polish. It can be done with diamond but I think it is more work than it is worth to learn how, especially if one isn't trying to polish many stones
I have tried different polishing pads and found the differences to be visible but small. This is an area where different jades seem to respond differently. Bill Myers, from the company that produces Rapid Polish, suggested using the paper side of a sanding disk. I tried that and found the results about the same as wood disks, although perhaps they are easier to acquire. I don't think the pad life would be as good either. The harder leathers help keep the surface smoother but the softer ones seem to give a brighter polish. I think the answer is: don't worry about it.
I tried other polishes after the initial Rapid Polish and found that Reynolds POLY-AL F improved the polish. This is a .2 micron aluminum oxide available from Diamond Pacific. Other polishes in the .1 to .2 micron range would probably work as well.
Rapid Polish doesn't actually work rapidly. It takes about three or four times as long for me to polish a jade cab as other polishes on other stones; it just does a better job. Many cutters are now recommending adding some vinegar to the polish. I have tried this, and have a small spray-bottle to spray the polishing disk. Sometimes I think it helps, sometimes I think it doesn't. Give it a try and decide for yourself. It does seem to deteriorate the leather pads faster. Ken Fitzgerald of Fitzcorp, Inc. recommends mixing any aluminum oxide powder one-to-one by weight with liquid dishwashing soap and using it as though it were diamond paste. Fitzcorp has done extensive laboratory testing of polishing compounds and plans to publish a book soon on tumbling and polishing- watch for it.
So, in short, my recommendations are:
Diamond: don't sand past 1200 or 1800 grit.
Silicon carbide: sand through 600 wet.
Dry sand on 600 grit until the jade burnishes.
Polish with Rapid Polish on what ever pad you have. If you are happy, stop.
For a better polish, start by getting some 1200 grit silicon carbide disks or belts.
If that isn't good enough, try the different types of wood and/or leather polishing disks.
Try other polishes after the Rapid Polish, sometimes they will improve the finish.
I know there are other ways of polishing jade but most are sensitive to the type of jade being polished and technique being used. This method has proved to be the least sensitive of any I have yet found
Contact Information for the Companies Mentioned:
Crystalite Corp. 8400 Green Meadows Dr. Westerville OH 43081 (800)777-2894
Diamond Pacific Tool Corp., 2620 W. Main St., Barstow, CA 92311 (800)253-2954
Fitzcorp, Inc. P. O. Box 565 Point Blank, TX 77364 (409)377-2409
Jade and More, P.O. Box 2381 Castro Valley, CA 94546 (510)538-7136
Myers Rapid Polish, P.O. Box 646, Keller, Texas 76244 (817)379-5662
Red Hill Corporation, P.O. Box 4234 Gettysburg, PA 17325 (717)337-1419
Rio Grande, 7500 Bluewater Rd. N.W., Albuquerque, NM 87121 (800)545-6566