Mandrel - Ring Polishing - Wood
Making a ring from metal clay may seem a little intimidating at first, but it's actually very easy. I'll go over the essential tools you'll need and give you some good ring building fundamentals to get you started.
Basic Ring Forming Tools
Finger Gauge – to measure for ring size
Ring Mandrel – to form a ring
Redy Pellets – to control the size of a ring
Freezer Paper – to keep a formed ring from shrink-locking to the mandrel during drying
Invisible Tape – to make a mandrel sleeve
A finger gauge is used to determine ring size. There are several different types: ring-style finger gauges, paper gauges and strip gauges.
- A ring-style gauge is a set of plastic or metal rings. There is one ring in each size that can be tried on until the proper size is found. Plastic gauges usually contain all whole and half sizes from 4 to 15 and are the most economical. Metal gauges often include quarter and three-quarter sizes, are more expensive, but more durable than plastic gauges. The most expensive metal ring gauges come in lovely boxed sets in either wide or thin bands and are usually used by jewelry stores and custom jewelers, and is overkill for most metal clay jewelry artists.
- A paper gauge is basically a miniature tape measure for the finger. Click here to download a paper sizer and instructions on use.
- A strip gauge works like a cable tie. A plastic strip is cinched onto the finger and reveals the size at a plastic stop. The plastic strip will measure in whole, half, quarter and three-quarter sizes.
A ring mandrel is used to form a ring on. Mandrels may be individual rods or a single mandrel that is either stepped or tapered. A ring can be formed to the most common sizes with any of the mandrel types. Here is a detailed description of the main types of mandrels that can be used for ring making:
Multi-Mandrel – The Multi Mandrel is my favorite ring-making tool because it's so easy to use and so versatile. The lightweight Multi-Mandrel was designed for creating wax ring models, but it's absolutely perfect for making metal clay rings. The set of 6 ring size mandrels are 5" long. There are two sizes on each mandrel. The smallest mandrel has size 4 on one end and 5 on the other, the largest has sizes 14 and 15. The mandrel is fitted into a stud on the mandrel stand. The stand can be placed so the mandrel is horizontal or vertical. The mandrels can be rotated on the stud, giving you access to every possible angle. The mandrels are available in whole and half sizes, and in aluminum or wood. A wood storage rack to store the mandrels is also available. The double-ended mandrels offer lots of ring-making real estate with no tapers to throw off your sizing. Multiple projects can be created simultaneously. The only drawback to this system is that you cannot use the mandrels to round or size a ring. I like the aluminum version better than the wood because the wood can expand with humidity and can be damaged much more easily than aluminum. The aluminum set offers a longer lasting tool.
Tapered Ring Mandrel - Tapered ring mandrels are made of steel so the metalworker can form metal with mallets and hammers. There are mandrels with sizes engraved into the steel, and there are mandrels with no markings at all. A finger gauge can be used to find the right size on an unmarked mandrel and a Sharpie marker can be used to mark the size. Any tapered mandrel will affect the accuracy of the ring size on wide rings. A wide ring formed on a tapered mandrel will have a difference of 1 to 1-1/2 ring sizes from one side of the band to the other which can result in a ring that is too tight or doesn't fit at all. To overcome this problem, be sure to center the middle of the ring at your desired size on the mandrel. I recommend that you make a wide ring one size larger to account for the width. A wide ring will always feel tighter than one with a narrow band of the same size. Steel mandrels tend to be fairly heavy, as much as 2lbs.
Another type of tapered mandrel is made of wood. A wooden tapered mandrel is made for polishing rings and is called a ring polishing mandrel. Some people use this type of mandrel to form metal clay rings on, but I do not recommend these because a ring polishing mandrel is much shorter than a steel mandrel, which means the taper is more extreme. While I don't care for a wood mandrel for metal clay ring forming, it is very handy to have for polishing, stone setting, drying and drilling.
Tapered aluminum mandrels are called ring sticks. A ring stick is a gauge meant for finding the size of a ring. The ring is slipped onto the mandrel and the size is determined by the markings on the ring stick.
A stand is available for aluminum and steel tapered mandrels that raise them off the work surface by about 3", giving you plenty of room to work. If you don't want to invest in a stand, a simple set of feet can be made for about $3.50 from polymer clay.
Low-Cost Mandrel Stand
Soften a 1 oz block of any brand of polymer clay by kneading it for 5 to 10 minutes (basically, you'll just smoosh it until it's nice and warm). Take ¼ of the clay and form it into a ball. Form the remainder of the clay into a cylinder twice as high as the ball. These are the feet for the mandrel. The small ball holds up the large end of the mandrel and the cylinder holds up the small end. Position the ball and the cylinder so the mandrel ends can rest on them and press the mandrel into the clay to create a seat. Make sure the mandrel is level. Remove the mandrel. Bake and cool the feet.
Stepped Ring Mandrel - A stepped ring mandrel is most often made from aluminum for wax ring creation. Each step has about 1 inch of space for each ring size. Some stepped mandrels come mounted on a rotating stand, making them very handy for metal clay ring making.
No matter what kind of mandrel is used, rings are never formed directly on the mandrel because metal clay shrinks a little bit as it dries, making it impossible to get the ring off the mandrel without damaging it. And if you did form a ring directly on a steel or aluminum mandrel, you'd soon learn about galvanic corrosion. Galvanic corrosion is something that happens when dissimilar metals are in contact in the presence of an electrolyte. An electrolyte creates an electrical charge that then corrodes the metals...and it's not pretty. The water and binder in metal clay are an electrolyte. Wet metal clay placed directly on steel will start the steel rusting immediately. Pits will form in the steel even before the clay is completely dry. The rust on the clay will remain after firing as ugly black pitted splotches that cannot be removed. Wet silver clay on bare aluminum causes pitting and corrosion on the metal. Silver clay will be blotched, discolored and pitted, and the damage is irreversible and hideous.
A simple sleeve made from freezer paper that fits over the mandrel allows easy removal of the ring as it dries and protects from galvanic corrosion. I call this a mandrel sleeve.
Mandrel Sleeve - To make a mandrel sleeve, cut a strip of freezer paper about 1” wide and 3” long. Wrap the paper, shiny side out, around the mandrel. Trim the strip so one end just overlaps the other end and use a small piece of tape (about 1/4 inch long) to hold it in place. The tape should not be on the mandrel. You want it just on the paper so the sleeve can be slid off later. Test to be sure you haven’t taped the paper to the mandrel.
A Ring Sizer is a special pellet or plug that is placed inside the ring shank during firing to control the size. The pellet is made from a special material that does not shrink or burn during firing. As the metal clay sinters, it shrinks tightly around the pellet so the ring is the exact diameter of the pellet after firing. After cooling, the ring is put into water to dissolve the pellet. Rings cannot be formed directly on Redy Pellets because they would not have any room to shrink and would tear.
Redy Pellets - Are pre-cast Ring Sizers available in half and whole US ring sizes from 4 to 12. Match the Redy Pellet size to the ring size you wear.
Redy Pellet Mold – The Redy Pellet Mold is a cost-effective way for metal clay artists to cast their own Redy Pellets Ring Sizers as needed. If you make lots of rings or teach classes, it may be more economical to make your own Redy Pellet Ring Sizers. Redy Pellet molds are available in whole, half and gang sizes. A half sized mold creates one pellet of each half size from 4 to 12. A whole size mold makes one pellet of each whole size from 4 to 12. A Gang mold makes 9 pellets all the same size. You'll need investment or paper clay to cast the Redy Pellets.
Investment - is a product that is used in casting metals. Investment is mixed and poured into the Redy Pellet Mold to cast ring sizers. Any type of silver, gold or platinum casting investment can be used, however the mold works best with a crystobolite-based product. Crystobolite is a silica-bearing product, so it must be used with a dust mask, or use a silica-free investment.
Our Ultra-Smooth investment makes Redy Pellets that are very smooth and strong, do not shrink, and can be de-molded in 25 minutes after pouring. They can also be used immediately after de-molding even though they are still slightly damp.
Silica-Free Investment is an alternative that does not contain crystobolite. Redy Pellets made from Silica-Free Investment are not as dense as traditional investment, and require 2 hours to set up before they can be de-molded, and must be allowed to dry completely before use. When casting with silica-free investment, a soapy-water release must be sprayed into the mold to avoid sticking. Just add a few drops of dish soap to plain water in a spray bottle and shake. Spritz the mold cavities before pouring the investment.
Paper clay can also be used to cast Redy Pellets. Press paper clay tightly into the mold cavity. De-mold after 6 hours. Air dry overnight or place in dehydrator for 2 hours.
Home-Made Ring Sizers – Here's a low-cost, low-tech way to make your own ring sizing pellets. This is a good method for the occasional ring maker.
You'll need a ring gauge, freezer paper, tape and paper clay or investment. Start by cutting a 1" x 3" strip of freezer paper. Roll the freezer paper up loosely so you have a 1" tall tube about 1/2 in diameter. Place the tube inside your selected ring size on the finger gauge. Release the tube so it expands and fills the ring. Pull the paper out of the finger gauge, holding the end in place while you trim and tape it. Use a good sized piece of tape to be sure the tube is strong. Place the tube inside the gauge and place the tube upright on a work surface. Slide the gauge down to the bottom of the tube, so that it rests on the worksurface.
Mix a teaspoon of investment with a few drops of water to make a pourable consistency and fill the tube. Allow it to set up, then remove the paper and allow to dry.
To use PaperClay, take small bits of paper clay and tamp it into the tube using a finger or pencil with eraser. The tube should be packed tightly. As you fill the tube, slide the ring gauge up a bit to give support at the level you are working on.
The inside of the ring shank will pick up any blemishes on the surface of the Redy Pellet, so fill and smooth any imperfections in the pellet before firing.
Steps to Making a Ring
1. Measure your finger to determine your ring size. Form your ring 2 sizes larger than this. For example, if your ring size is 7, you would form the ring at size 9. (I often add an additional 1/2 size when the ring shank is wide and 5 cards or less in thickness.)
2. Fit your mandrel with a mandrel sleeve (see instructions above). The ring is created directly on the sleeve. As the ring begins to dry, it will shrink a little. This can be enough to stress a seam and cause it to tear. To avoid tearing, I allow the ring to dry for 10 or 15 minutes, then slide the sleeve down one size on the mandrel so it can complete drying on the outside without any strain. Once firmed up, the sleeve with the ring on it can be slid off the mandrel and dried on a cup warmer or other drying device. Once the outside feels completely dry, the mandrel sleeve can be removed and the inside can finish drying. Do not try to remove the mandrel sleeve until the outside of the ring feels totally dry to avoid breaking or distorting the ring.
3. Once your creation is ready to fire and completely dry, place a Redy Pellet in your desired ring size inside the shank and fire. Don't worry that the ring is larger than the pellet. During sintering the ring will shrink tightly around the Redy Pellet, resulting in a ring that is exactly the size of the pellet. If the top of the ring is wider than the shank, the ring will have to be propped up so it doesn't warp. The ring can be placed on a fiber blanket or in a dish of vermiculite or alumina hydrate for support. Be certain that nothing gets between the Redy Pellet and the metal clay as it sinters and shrinks.
4. After firing and cooling, the Redy Pellet is removed from the ring by dissolved it in water. The ring is then polished and finished as desired.
Ring Making Tips
What Clay To Use
Sintered fine silver is soft and brittle, so it dings up pretty quickly and its fairly easy to break when its thin. Low-fire clays such as ACS 650 Low Fire and PMC 3 have the smallest particle sizes so they sinter more densely than other formulas and are the preferred clays for creating rings.
Recommended Firing Schedule for Silver Clay Rings:
PMC 3: 1650F for 2 hours in a digitally controlled kiln maximum strength
ArtClay Silver Low Fire:1650F in a digitally controlled kiln maximum strength
Rings can be fired with a torch, however the end product will not be nearly as strong as kiln firing. Consider the fact that a flat strip made from PMC3 and fired at 1650F for 2 hours can be formed on a ring mandrel into a ring. The same strip fired by torch will break when attempting to form it on the mandrel because sintering is a process that happens over time and the longer the piece is left to sinter at ideal temperature, the more fully it is sintered and therefore the stronger the final product is.
If you torch fire rings, be very careful in wearing them. Treat them as cocktail rings. I also wouldn't recommend selling rings that have been torch fired because customers will expect a silver clay ring to be as strong as a sterling silver or gold ring, and they just aren't. If you plan to sell your rings to the public, fire them in a digitally controlled kiln for maximum strength, tumble polish to give added strength through work hardening, and be sure the customer understands that metal clay is a sintered material that does not have the same properties as sterling silver and gold so they treat their rings with care.
How Thick to Make the Shank
5 cards thick is a good standard for rings. For heavily textured rings, make sure you have a floor of at least 3 cards thick.
Making a Half-Sized Ring with a Whole Sized Mandrel
If you need to make a half-sized ring and only have a whole sized mandrel, make the mandrel half sized by making the mandrel sleeve thicker. Simply cut a longer piece of freezer paper and wrap it one complete revolution around the mandrel. You'll need to use the proper half-size Redy Pellet when firing.
Removing the Ring Sleeve
Once the outside of the ring feels dry, remove the sleeve so the inside can dry. Place a needle tool on the top edge of the sleeve and collapse it downward. Pinch the sides of the sleeve together and slide it out of the ring shank. Be careful not to nick the inside of the shank as it will be soft. The ring can be speed dried on a hot plate or left to air dry. Be very careful in handling the ring at this point since the inside is still wet and the ring can easily collapse. Save the sleeve! It can be used again and again.
When you have 2 ends that meet and you want to blend them, use a small ball stylus or clay shaper to “stir” the ends together rather than trying to add water and paste them together. The result is a much more reliable joint.
Seams should be joined in a bias cut rather than a straight up and down cut. This gives more area to joint and results in a stronger seam.
Use the seam as a design element or position the seam so it is at the top of the ring and will be covered with a decoration or top.
Metal clay shrinks a little bit as it dries. To keep the ring seam from tearing, I move the ring to a smaller mandrel size as soon as it’s firm enough to hold its shape. I usually let it air dry for 10 to 20 minutes and then I slide the ring to a mandrel 1 size smaller, giving a little bit of slack allows the clay to shrink unobstructed. I’ve seen seams open when no slack was given. This also usually means the ring was not thick enough.
Rings have to be formed larger than their final size to allow for shrinkage. I prefer to form rings 2-1/2 sizes larger than my ring size. For a size 7 ring, I form it at 9-1/2 on the mandrel.
Investment can be used to make placeholders for stones that must be set after firing. Make a seat for your stone or object, fill the cavity with investment and allow to set up. Then fire. After firing, the investment is dissolved away and the stone can then be set in the perfectly sized seat.
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