Subtractive Wax Working

Transcription

1 Society of North American Goldsmiths Artists Designers Jewelers Metalsmiths January TECHNICAL ARTICLE Please note the following correction to the Technical Article TIG Welding for Metalsmiths, which appeared in the October 2009 issue: On page 15 the captions for the top images were inadvertently reversed. The image on the left should have read Correct grinding technique... and the image on the right Incorrect grinding technique... The corrected version is in the SNAG News archives. Subtractive Wax Working by Jim Bové This article addresses some simple subtractive techniques that can be used on hard waxes, such as file-a-wax. I have found that many people neglect building subtractive skills when working in wax, the tendency is to add wax on top of wax and remove only when necessary. In my personal experience, students tend to gravitate towards that additive approach if left on their own. It feels more natural and is more in line with the way they approached 3D materials in the past. However, once subtractive techniques are introduced, their work gets thinner, tighter and gains the control they need in order to fully realize their work. The symmetrical high-domed ring is an excellent project for building these subtractive skills. The key to getting the most out of this exercise is to focus on the even thinness of the ring and its symmetry. It s true that students, and even seasoned artists, want to jump right in and create their grand visions, but taking the time to learn the material will only make life easier later. The problem is that the wax seems, and is, fragile. Even though we understand the end result of our labors will be a finished metal piece, it is still a hard thing to accept the strength that will come when the piece is in metal, while the work is in wax form. To solve this problem, whenever using a hard wax create a wax gauge. This is easily made by carefully filing and sanding the wax to B&S gauge thicknesses. I generally start around fourteen gauge and end at twenty-two gauge. For most of my work, that range is the most useful. Some time spent making a gauge will be beneficial later and, with care, the gauge can last a long time. (Tip-If the gauge itself brakes, just use clear tape to fix it. Since you are reading the transparency, the tape will not affect the gauge s usefulness.) How to make a wax gauge: Cut a strip of the type of file-a-wax that you will use. Make it about one centimeter in width. Mark off even increments that are about one centimeter or more in length. Some people use a spiral or skip-tooth saw blade to rough out the steps in thickness. Alternatively you can use a rasp and file. Finish as you normally would using various sandpaper grits. Check the gauge by fitting it to the appropriate B&S gauge slot. Be sure to check both sides, there is a tendency to work one side more than the other. You do not want any unevenness in your gauge. How to use: Hold the gauge up to the light; you will be able to see a gradation in the scale that directly relates to the thickness of the wax. The darker the wax, the thicker it is. Likewise the lighter the wax, the thinner it is. I scratch the corresponding metal gauge thickness into the wax for quick reference. Compare the ring (or whatever future project you take on) to the wax gauge to judge the thickness. In the beginning, it is a good idea to have sheets or wires of metal beside you that represent the gauge sizes you are seeing. It helps to reinforce just how strong the ring will be once it is cast. Many people will gravitate back to thicker and thicker rings once they break a wax model they have been working on. It s natural. Just take a deep breadth, repair the piece and reinforce to your self that the final piece will be strong by handling the sheet metal or wire that represents the gauge you are working toward.

2 Society of North American Goldsmiths Artists Designers Jewelers Metalsmiths January Views of the wax gauge. Some basic tools that I use when working in wax are dental picks, a small ruler, wax files and wood rasps and a set of Wolf carving tools. Starting the ring: After you have made your wax gauge, square up a block of file-a-wax. Use a carpenter s square to ensure it is even on all sides. Take the block to a medium emery paper to even out any side that needs it. Select the thickness of the ring you desire to make and layout a scribe line using dividers on the wax block. (Tip-You may use tube wax for creating future rings, but I find that this process is good to know and builds your skill set.) Carpenter s square, dividers and a block of wax ready to be cut. Note the area on the right. It is a low spot indicating that the wax still needs to be sanded down. A bandsaw is a very easy and clean method for working the wax. Hard waxes will not clog wood working tools and, if the bandsaw is properly adjusted, the cut can be very clean and straight. At my home studio I have a fourteen-inch bandsaw adjusted using the dollar bill method (look this up on-line, it s an easy way to set the guides) and I can shave off the thickness of business card with ease. Please note, always wear eye protection when working with power tools. Follow all safety guidelines when using any tool. Clean up the cut piece of wax and check for square. I use a figure eight motion when sand ing. I feel that Vthis gives even pressure to all sides. Alternatively, use an X pattern. Check for level and evenness. If you can see any light coming from between the wax and the straight edge, the surface needs to be sanded down more. Make corrections for any part out of square. Taking your time here will ensure success later.

3 Society of North American Goldsmiths Artists Designers Jewelers Metalsmiths January In my class I demonstrate hand-sawing techniques using a spiral saw blade, but I find this trick to work very well. I use a wood drill bit to bore the hole for the ring size. These bits are intended to create a pilot hole that allows you to drill half way, then turn the piece over and continue drilling from the other side. This is not necessary in wax as we are not concerned with tear-out. The key is to be patient and slow. Allow the bit to scrape the wax away. If you feel the wax chatter or move on you, you are going too fast. Check your progress, as the bit gets close to cutting all the way through, you can either stop and pop the thin wax disk out, or slowly complete the cut all the way through. The sharper your bit is, the easier this will be. The hole will need to enlarged depending on the difference between ring size and drill bit size. I find that I often only need to use course sandpaper at this stage. Be careful to not bring the ring out of round. If the difference is that great, scribe a reference line with your dividers to file or sand back to. A cheap spade wood drill set works very well on wax. Select a bit that is slightly smaller The key is to drill very slowly than the final ring size. Use files or and to clear debris as you go. sandpaper to enlarge later. Laying out the pattern: Because we took our time and made sure the sides of our wax were square, now we can use the block to find the centerlines of our circle. Using your carpenter s square, scribe a square around the circle. Now measure the length from corner to corner and divide in half. Transfer these measurements to the other side. Note: it is very important that the measurements be on both sides of the wax. Even a relatively thin ring is hard to shape without a guideline. If you do not have a guideline, do not eye-ball it. Not for a symmetrical ring, it just won t work. Scribe lines laid out. Notice I left plenty of room up top for the dome part. Create the shape of the dome by measuring and using circle, oval or ring templates or with dividers. A rounded top will be easier to shape on the inside, a squared off shoulder is harder to hollow out and keep even. Choose the level you wish to work at.

4 Society of North American Goldsmiths Artists Designers Jewelers Metalsmiths January Sawing out the ring: Depending on your personal comfort zone, the bandsaw can be used to rough out the ring. Use straight cuts and avoid the temptation to follow the curves of the ring. As you progress, you will get cleaner, but a series of straight cuts is easier to control and safer. Use a scrap piece of wood that is close to the wax thickness as a push stick if needed. Bandsaw used to shape ring. Make straight cuts Hand sawing the ring to shape. and file to shape. Use a skip-tooth or spiral saw blade to cut out Shaping the ring: I like to use rasps to shape the ring. The wider surface of the rasp is easier to control than a thin jeweler s wax file. The combination rasp is a nice one to use and is found in any tool section of a hardware store or Sears. After using the rasp, take a mill file to the piece. Have a file card handy to clear any debris, but more often than not, a short rap on the side of your bench will clear the file. Avoid using files that may contaminate your wax with metal filings or other matter. Once the profile of the ring is set, transfer your centerlines to the sides. Find the center of the side by either measuring, or by using a divider and estimating. In either case, always scribe the centerline from both sides, this way you will be certain that you measured correctly. Adjust the dividers until you reach center from both sides. Now you can determine the angle of taper to the ring shank. Once it is laid in, use the rasps and files to shape the wax. After filing I use sandpaper followed by a fine scotch bright pad. Some people use lighter fluid to smooth out the wax surface, but this is a little noxious. Try eucalyptus oil if you like to take your work to that stage. It works just as well and smells nicer.

5 Society of North American Goldsmiths Artists Designers Jewelers Metalsmiths January Shaping the inside of the ring: Now that the profile and shape of the ring has been laid out and finished, it is time for the inside. This is where your skills will be tested. A flex shaft is an easy way to begin. Start on a thick area and go slowly at first. A light touch is best. Select a bur that most closely fits the outside contours of your ring. Once again, inexpensive wood working burs work well and remove the wax quickly. By hand, use dental bits (they can be modified by grinding them. I ask my dentist for anything, including broken bits, that he is willing to part with) or Wolf carving tools as needed. Most often square shouldered rings will need to be carved out in the corners by hand. Your goal is to create an even thinness throughout the ring. Make the dome slightly thicker than the shank. See if you can create a hollow shank that is 18 gauge with a dome that is around 16 gauge. The key is evenness. Hold the ring up to the light as you work on it and compare it to your wax gauge. Rotate the ring so that you can compare all areas to the gauge. Conclusion: The hollow, high-domed ring not only saves in metal and weight, but is comfortable. The flesh of the finger can gently squeeze into the hollow form of the shank and the dome. I do own solid rings that have some size to them and have made them myself. The heavy feel does have something to it, but this is about learning control and building your technique. Give it a try. See how symmetrically you can make the ring and how evenly the thinness. This approach uses a combination of normal jeweler s tools and hardware store tools. The idea behind this was to get you thinking about how you can use what is available to your advantage. Please share your wax working techniques and your approach with us. I would love to combine many tips and tricks into one article, or maybe there is someone out there who would like to take on the additive portion of wax working. Note: I chose to omit information about sprueing, investing and casting your waxes on the assumption that the information is readily available from other sources. This does not mean that someone out there can t shed new light, or explain it better than it has ever been explained before, but it was not the focus of this article. SNAG News will pay up to $125 per page (up to 4 pages) for informa tive technical articles aimed at any level from intermediate to advanced, from student to the highly skilled professional. If you teach a workshop, have a clever bench trick or technique of interest to other jewelers and metalsmiths, or have more academically based technical research, please share it with our SNAG community. Send your submission to James Thurman, 418 Marietta St., Denton, TX James.Thurman@unt.edu