"The Art of Intarsia"
by William Grundke

Part Seven

Figure 38

Special Techniques
   The previous six chapters of this series have shown how to make an intarsia from start to finish. Subjects covered in these installments were:
Part One, in the December 1981 issue - The selection of a design, transferring the pattern, suitable gem materials, and sawing.
Part Two, January 1982 - Flat lapping and the various types of grinding involved.
Part Three, February 1982 - Cementing techniques, including the use of an intarsia press and a cementing jig.
Part Four, March 1982 - A beginning project to produce a small intarsia for mounting in the lid of a jewelry box.
Part Five, April 1982 - Instructions for producing a larger, more detailed intarsia picture.
Part Six, May 1982 - Backing and framing your intarsia.

Figure 39

   Just about all of the conventional procedures for making gemstone pictures were covered in those chapters, plus some methods of a more special nature. As one progressed I this art, even more special techniques will be developed. Somewhere along the line the intarsia maker will undoubtedly want to produce a picture(s) that includes areas or parts that require a different working method - perhaps even the development of special tools or accessories. This is where much of the fun comes in - meeting the challenge while producing an artwork of unusual beauty. It is also enjoyable to be asked, "How did you do that?"
   As an example of special techniques, let's take a look at the intarsia, Cannery Row (Fig. 38). It was shown in color at the beginning of this series on page 16 of the December 1981 issue. In this picture, the lines representing the masts and rigging of the boats required a different approach, if they were to be kept straight and in the correct locations.
   The basic procedure for Cannery Row was the same as described in previous installments. It was built up by units, as usual. Eventually the top units were built into the assembly illustrated in Fig. 39A. At this point it was the time to put in the slots for the masts and rigging lines designated by arrows in Fig. 39A. All the other lines and masts were put in as the individual units were built up.
   To make the slots I used a Gy-Roc Preformer Saw (Fig. 40) which is manufactured by Tagit, Pico Rivera, CA 90660, and sold by dealers for Johnson Brothers, 19434 Oxnard St., Tarzana, CA 91356. On this type of machine, the blade is on a swinging arm overhead, and is lowered onto the stone being cut. For work like that being described here, I recommend this type of saw because you can place the intarsia unit in the proper location, then do not have to move it as the cut is made. Possibly one could not put in slots, such as those for the masts and lines, on a conventional trim saw, but it would be extremely difficult to keep them from wandering on such long cuts. A regular trim saw is fine for shorter cuts like those required for the barn scene described in Part Five in the April issue.
   For the rigging lines I used a thin saw blade. A thicker blade was substituted for the masts.
   Only one slot should be sawed at a time, then it should be filled with the appropriate gemstone piece. After the cement has hardened, you can proceed to the next line or mast. If you attempt to make several slots, then fill them later, pieces of the intarsia can be dislodged, and/or parts of the picture can become misaligned.
   I also employed the Gy-Roc Preformer Saw to cut the stone piece for the masts and lines - some of these strips were very fine - only 1/8" thick. The same procedure was followed: Lay a stone slab fo the correct color and dimensions on the table and bring the saw blade down.
   Next the strip is lapped on the sides. I usually use 220 grit, but in some remote cases 400 grit might be required (as discussed in previous installments). If you must use 400 grit, be especially careful of "grab." With either grit, I recommend working near the center of the lap wheel to reduce this problem of "grab." I hold the stone strip on the lap with my fingers and "lean" a little harder on one edge to taper the gem material a little. As described with Fig. 26 (Part Four, March 1982), this makes it easier to fit the stone piece in the designated opening. When the piece is inserted in the recess (slot), it slides in until the cross section area of the correct dimension is reached, providing a snug fit.
   For some craftspersons, especially beginners, using a mechanized lap might be a problem. If so, the work could be done by hand with grit and water on a sheet of glass or steel. The process is described completely in the article, Polishing Stones by Hand, in the January 1982 issue, (the same issue in which this series covered lapping).
   When a mast or line strip ahs been cut and lapped completely, cement it in its designated slot. Remember to process just one at a time.
   Note in Fig. 38 that in the bottom part of the picture there are reflections in the water. Before these were put in, the entire bottom unit (Fig. 39B) was completed. This unit was then positioned on the performer saw table, and the blade was lowered to it to make a straight cut down into the stone. The uit was repositioned and more cuts were made. Some of these cuts are designated as straight lines at "X" in Fig. 39B.
   A diamond abrasive carving tool, known as a straight router (available from our suppliers) was then used to put wavy edges on these cuts. This carving tool can be used with a flexible shaft uit or motorized handpiece, following the manufacturer's instructions and standard carving techniques. Making the wavy edges will create the appearance of reflections which you see in water.
   I then chose some gem material of appropriate color for the reflections. From it some straight pieces were cut which would just fit into the wavy slots. They were epoxied in place. Surrounding these straight pieces, of course, were empty spaces along the wavy edges. To fill these, some of the same gem material chosen for the reflections was crushed and mixed with epoxy. This mixture was poured in around the straight pieces and allowed to harden. Note: Safe methods of crushing gem material are covered on page 20 of the April 1982 issue (Part Five of the series).
   For smaller reflections I do not cut the saw slots. I just use the diamond straight router to make wavy recesses and fill them with the mixture of crushed stone and epoxy.

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. . . ...Figure 40. . . . . . . . . . . . .. . ... ... . . . . . . . . . . Figure 41. . . .


   When a hole must be drilled in an intarsia, it is sometimes difficult to get it centered exactly where you want it. Diamond gem drills and routers have blunt tips and can waver slightly. Therefore, it is best to make a hole with a drill of small diameter first. Then use a larger drill or router, following this small centering hole.
   If you have access to an ultrasonic drill, it will work very well for making the fine centering hole. Then enlarge the hole with a diamond router.
Carving Tools
   Checking the stocks at rock shops and in catalogs form our suppliers will reveal that there is a good selection of carving points and wheels with many different head shapes. It is a good idea to acquire as many of these tools as you can, building up a selection of various shapes to be used for this special jobs. If you are a dedicated do-it-yourselfer, there is a book, How to Make and Use Gem Carving Tools by Forrest W. Pond, which is available for $2.50 form mail-order suppliers and at rock shoos.
   Previously we have discussed finishing intarsia surfaces on conventional lap wheels or by hand. There are also slab lappers and polishers, such as the one shown in Fig. 41, on which a metal lapping wheel or a polishing buff are attached to an overhead arbor. The wheel or buff is swept Back and forth over the surface of the stone. The machine shown in Fig. 41 is from Covington Engineering Corp., P.O. Box 35, Redlands, CA 92373.
   Some artisans also use vibrating laps. This can be satisfactory if the intarsia is composed of gem materials that are not delicate or soft. However, breakage is possible; proceed at your own risk.
   Different intarsias require a variety of techniques. And, it is amazing what can be accomplished when the imagination is turned loose. So, why not see what you can improvise and above all, enjoy!
   This concludes the information on making gemstone pictures. In our next installment, we will discuss intarsia cabochons. . . . . . . . . . . . . . . . . . .. . . . . . .. .

See the Author's Work At the CFMS Show
   If you would like to actually view the intarsias of William Grundke, be sure to attend "Gems by the Sea," the 43rd Annual Convention and Show of the California Federation of Mineralogical Societies. This event, with its many competitive and special exhibits, demonstrations, lectures, dealer sales, swap area and much more, will take place August 27 through 29 at the Long Beach arena and Convention Center, Long Beach, California. The host will be the La Pacifica Group. Now is a good time to start making plans to take in this great show. (Personal note: I met the author William Grundke at this show and saw an intarsia for the first time, "Silent Night." I had only previously seen this type of work in issues of the Lapidary Journal. He told me about and invited me to a class on how to create intarsias being taught at Leisure World, through Saddleback Community College. It was over 10 years later that I met his son, Conrad, who had started teaching that class and still is, and I enrolled. - Dennis Paul Batt)


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