How to Use a Mandrel

Mandrels are rods of various diameters. They are used to help shape metal, glass, plastic or clay so that it will have a specific diameter hole after it has hardened and cooled. Mandrels can be made of metal as long as it has a higher melting point than any material you intend to work. Bead mandrels can be made from metal coat hangers. Mandrels for sizing rings are tapered from end to end and marked for easy use.

Things You'll Need

• A set of jewelers' mandrels
• Ring sizing mandrel
• Metal coat hangers
• Needlenose pliers
• Clay, metal or glass to be worked
• Propane or MAPP torch
• Vise grips
• Leather work gloves
• Wrap-around eye protection
• Coffee can full of vermiculite
• Petroleum jelly
• Paper towel
• Potter's or self-hardening clay
• Fine sandpaper
• Rubbing alcohol
• Soft cloth

Instructions

Using a Mandrel to Make Glass Beads

1. Cut full sections from the bottom of several coat hangers. These will be used as bead-making mandrels. Coat hangers will usually yield one 15-inch long mandrel each.

2. Light your torch and adjust the flame according to the manufacturer's directions. Put on leather work gloves and wrap-around eye protection. Glass can shatter from heat stress and fly up into your eyes faster than you can blink.

3. Hold one mandrel in your off hand. This is the one that is not your dominant hand. Hold the material to be worked in a pair of vise grips or tongs in your dominant hand. Slowly bring the material to be worked into the flame. Once it becomes bright orange, touch the material to the mandrel. Turn the mandrel slowly to form a bead around one end.

4. Fill a metal coffee can half full of vermiculite. Heat it to 500 degrees Fahrenheit. Set the remaining glass from Step 3 in a can of vermiculite to cool. Roll the mandrel with the molten glass bead on it back and forth between your fingers until the glass becomes smooth. Push the mandrel into the coffee can full of heated vermiculite until it cools.

Using a Mandrel to Make a Ceramic Ring

1. Coat a ring-sizing mandrel in petroleum jelly, and wipe away the excess with a paper towel.

2. Take a pinch of clay and roll it into a half-inch-diameter ball.

3. 

   Roll the clay ball back and forth on a plastic cutting mat until it becomes a thin snake about 4 inches long. Fold the snake over on itself and hold it at the fold and at the two loose ends. Twist the snakes together as shown in the diagram.

4. Wrap the twist of clay around the ring-sizing mandrel at the marking for the ring size you wish to make. Smooth the ends of the clay together using water or slip, which is liquid clay.

5. Put the mandrel in a vise or stand it upright so that the clay is not touching anything except the mandrel while it dries.

6. Carefully slide the ring off the mandrel when the clay has dried to white. Use fine sandpaper to smooth any imperfections. Finish the ring as desired.

7. Clean all traces of petroleum jelly and any clay residue off your mandrel with a piece of soft cloth and rubbing alcohol. Store upright until mandrel dries completely.

Tips & Warnings

• Use steel mandrels for bending any metals. Although aluminum mandrels are available at lower cost, they are too soft for working with anything but clay, foil or aluminum.

References

• Using Mandrels to Make Glass Beads

Resources

• Using Mandrels to Make Glass Beads