Waterproof Mandrel Paper Pkg/10

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Sku : ACC-107

12" x 7-1/2"

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Waterproof Mandrel Paper

This paper is essential when forming and drying metal clay on any type of wooden or metal mandrel. Making a ring from metal clay may seem a little intimidating at first, but it's actually very easy.  Find detailed instructions below to create a ring and information on mandrel types. 

Made in the USA

Make a sleeve that can be slid off the mandrel with the project in place. This sleeve can go into the freezer, on the hot plate or in a dehydrator. Do not place in an oven hotter than 450°F / 232°C. This paper is essential when forming and drying metal clay on any type of wooden or metal mandrel.

To create a mandrel sleeve, cut a strip of mandrel paper 1/2" to 1" wider than the width of your project and just long enough to wrap around the mandrel and overlap by about 1/8". Wrap the mandrel paper strip, shiny side out, around the mandrel and secure it to itself with a small piece of invisible tape. The tape should not be on the mandrel. Test the sleeve to be sure it can be slid on and off. 

Basic Ring Forming Tools

  • Finger Gauge – to measure a finger for ring size
  • Ring Mandrel – to form a ring
  • Ring Sizer Mold – to control the size of a ring
  • Waterproof Mandrel Paper – to keep a formed ring from shrink-locking to the mandrel during drying
  • Invisible Tape – to make a tube from mandrel paper

Finger Gauge

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. Ring-style gauges are available in plastic and metal.
  • A paper gauge is basically a miniature tape measure for the finger.
  • 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.

Ring Mandrel

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.

Important Note

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.

Here is a detailed description of the main types of mandrels:

Multi-Mandrel – The Multi Mandrel is easy to use and versatile and is available in wood or aluminum. These lightweight Multi-Mandrel were designed to create wax ring models, but it's also perfect for making metal clay rings. Most sets include 6 ring size mandrels that 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. They are available in whole and half sizes, and in aluminum or wood. 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 aluminum version may be a better choice 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 metalworkers can form metal with mallets and hammers. There mandrels are are engraved with sizes, and some without. A finger gauge can be used to mark the right size on an unmarked mandrel. 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 for a good fit. We also 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. Some mandrels have a hole in the end to allow them to be fitted on a stand, and there are also mandrel rests to hold the stand. Steel versions 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. Some people use this type to form metal clay rings on, we do not recommend these because a ring polishing mandrel is much shorter than a steel mandrel, which means the taper is more extreme. It is very handy to have a polishing mandrel for polishing or 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 worksurface 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 from polymer clay.

Stepped Ring Mandrel - Stepped ring mandrels are made from aluminum since they are designed for wax ring creation. Each step has about 1 inch of space for each ring size. Some stepped mandrels come already mounted on a rotating stand, making them very handy for metal clay ring making, but a bit heavier than the Multi-Mandrel system.

Mandrel Sleeve - To make a sleeve, cut a strip of waterproof mandrel 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.

Ring Sizers

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 Ring Sizer Mold because they would not have any room to shrink and would tear.

Ring Sizers - Cool Tools pre-cast Ring Sizers are available in half and whole US ring sizes from 4 to 12. Match the Ring Sizer size to the ring size you wear. Genuine Ring Sizers have the size molded into the end of the pellet so there is never a mix-up in sizes.

Ring Sizer Mold – The Ring Sizer Mold is a cost-effective way for metal clay artists to cast their own Ring Sizer Mold as needed. The 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 to cast the Ring Sizer

Investment - is a product that is used in casting metals. Investment is mixed and poured into the Ring Sizer 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 Ring Sizers 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. Ring Sizers 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 which is made simply by adding a few drops of soap to plain water in a spray bottle.

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. (We recommend adding an additional 1/2 size when the ring shank is wide and 5 cards or less in thickness.)

    1. 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, 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.

    1. Once your creation is ready to fire and completely dry, place a Ring Sizer Mold 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 Ring Sizer, 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 Ring Sizer and the metal clay as it sinters and shrinks.

    1. After firing and cooling, the Ring Sizer 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 dings up quickly. Sterling silver clays contain a small amount of copper which will give jewelry the strength needed to withstand every day use.


How Thick to Make the Shank

4 to 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.

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, dehydrator 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 ease the ends together. In some cases, paste or syringe will aid in filling gaps. Once the piece has been completely dried, re-inspect the seam to make sure the surface is smooth with no valleys. Paste will shrink as it dries. Add additional paste to refill any gaps and sand to smooth out the area.

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.

Seam Stress

Metal clay shrinks as it dries. To keep the ring seam from pulling apart, move the ring to a smaller mandrel size as soon as it’s firm enough to hold its shape. Let it air dry for 10 to 20 minutes and then slide the ring to a mandrel 1 size smaller, giving a little bit of slack allows the clay to shrink unobstructed. seams will tend to open when no slack was given.


Rings have to be formed larger than their final size to allow for shrinkage. We suggest forming rings 2 to 2-1/2 sizes larger than the require ring size. For a size 7 ring, form it at 9 to 9-1/2 on the mandrel. Refer to the packaging for the type of clay being used for shrinkage information.


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 according to metal clay package instructions. After firing, the investment is dissolved away and the stone can then be set in the perfectly sized seat.

All orders placed before 12:00 (CST) will ship the same day, Monday through Friday. Orders placed after 12:00 (CST) will ship the next day, Monday through Friday. If there is a problem with processing your order, we will contact you.

Free Shipping: US Orders Over $125.00

Paragon & Evenheat Kilns ship separately, and take 2 - 3 weeks to be delivered, direct from the manufacturer.

Same-Day Shipping

Orders before 12:00 pm CST, M-F

Next-Day Shipping

Orders after 12:00 pm CST, M-F

Free Shipping

U.S. Orders Over $125.00

Kiln Shipping

2-3 weeks delivery for Paragon