Introduction: Illuminated Polymer Clay Necklace
Blinking lights on necklaces, bracelets, hats, or sunglasses are commonplace at festivals and fairs, but can those lights also be used for wearable art such as necklaces, bracelets or earrings? Is it possible that LEDs could be integrated into a work of art that is functional and beautiful? I think so!
My goal was to create a beautiful necklace in polymer clay that highlights its translucent and opaque qualities. What if I embedded a softly glowing light within each hollow bead? The result after a number of less-than-perfect prototypes was a necklace that is stylish, comfortable, easy to operate, and is beautiful with or without the lights illuminated.
What follows is a detailed tutorial that is easier than it might seem at first glance. Read through the full tutorial and the notes before you get started so you have a clear idea of what is involved, including the precautions you should take to be safe and to create a beautiful, successful work of art.
Step 1: Materials and Tools List
- Translucent and opaque polymer clay in your choice of colors
- White 3mm diffused "through-hole" LEDs (like these from Amazon.com)
- 24 AWG silicone-covered stranded core wire (Adafruit.com)
- 1 2032 3V coin cell battery
- LilyPad sewable battery holder with switch (Sparkfun.com)
- IC hook test leads or Alligator test leads
- Solder iron and lead-free solder
- Embossing heat gun
- Hook-and-loop fastener
- Wire stripper tool
- Wire cutter tool
- Round-nose pliers
- Hand-drill or Dremel
- Hot glue or E6000
- Poly Bonder Polymer Clay Adhesive (or Bake and Bond)
- Spacer beads with large holes
- Necklace clasp of choice
- Solid rubber jewelry cord (such as this from Amazon)
Step 2: Create the Domed Bead Halves
This tutorial assumes you are somewhat familiar with polymer clay. Create the components for your hollow beads by forming half-domes with a mostly translucent (some opaque clay is fine) medium-thin sheeted clay. You want the top half of your finished bead to allow the LED light to show through the clay. I used a mixture of translucent and opaque clay to create patterns. Hold the uncured sheet of clay up to a light to see if light comes through the clay. Translucent clay becomes a bit more translucent after curing.
Focal Bead for Battery Holder - Make One
- Cut two 2" (or larger) round shapes out of the prepared medium-thin clay sheet with a clay cutter.
- Press onto a light bulb or other heat-safe domed object - I used Sculpey's Hollow Bead Maker, and HERE is a tutorial from the company.
- Cure at the recommended temperature and time listed on the polymer clay package.
- Pop the cured domes off their forms and sand the edges to create a smooth fit between both halves of the focal bead.
- Sand and buff the outside surfaces if needed/desired.
Necklace Beads - Make 4 or More
- Cut eight (to make four complete beads) 1.5" to 1.75" round shapes out of the prepared medium-thin clay sheet with a clay cutter.
- Press onto light bulbs or other round, heat-safe objects to create a dome. Again, I used Sculpey's Hollow Bead Maker. You will need two bead halves per bead.
- Cure the domes at the recommended temperature and time listed on the polymer clay package.
- Pop the cured domes off their forms and sand their edges flat to create a smooth fit between bead halves.
- Match pairs for best fit, then decide which half of each pair you like best for the top side of the beads.
- On the bottom (back) piece, drill two 1/8" holes in the sides of the domes, slightly above the "equator" so the finished bead will hang correctly. See picture.
- Sand and buff the outside surface of each half as needed.
Smaller Domed Inserts - Make at least 4, for the Necklace Beads
- With thin sheets of translucent clay, make as many 1" diameter domed bead halves for the number of main beads needed for your project. These will be inside each larger bead.
- Drill a 1/8" hole in the middle of each insert. These inserts will hold the LEDs.
Step 3: Add the LEDs and Prepare the Wires for Soldering
The 3mm "through-hole" LEDs have two legs, a longer and a shorter wire. The longer wire is the positive (+) side and the shorter wire is (-). We will be soldering these legs to the silicone-covered wire.
- Use a permanent marker to color the negative (shorter) leg on the LED, then trim the legs to about 1/2" with wire cutters.
- Insert the shortened LED legs into the hole of the LED holder, with the LED facing down and the legs on the top side of the dome. (See image)
- With needle-nose pliers, make an open loop and bend the wires so they rest flat against the polymer clay dome. Repeat for each LED holder you will use.
- Apply Poly Bonder or Bake-and-Bond liquid Polymer Clay to the rim of the LED holder dome and position it into the center of the back side bead half, keeping the two holes free.
- Repeat for all of the LED holders.
- If using Bake-and-Bond, use an embossing tool (heat gun) to gently warm the bead parts and lightly cure the Bake-and-Bond. We will cure the beads fully later. The heat of the embossing heat gun will not damage the LED, but please be careful. Keep the heat gun moving, about 2” away from the clay. If the clay begins to smoke, the heat is too high. Open a window for fresh air if this happens. The fumes are non-toxic but I still would want fresh air if this happens.
- Cut the flexible wire into approximately 3" pieces.
- Strip about 1" of the silicone sheathing on both ends with the wire strippers.
- With soldering iron, tin the ends of the wires by melting a bit of solder to keep the stranded wires from fraying. I like to twist them before tinning.
Step 4: Prepare the Battery Holder (Involves Soldering) and Test the LEDs
Now let's prepare the focal bead that holds the battery holder, which will provide the power to the LEDs.
- Solder a prepared wire to each of the holes in the battery holder, trimming away any excess wire.
- Position the battery holder into the bottom half of the larger focal bead you made earlier. Thread one positive and one negative wire through each hole on both sides of the bottom bead half. (See image)
- Now, mark the negative wires with a permanent marker. IMPORTANT: It is very easy to mix up the positive and negative wires. Check and double-check before and after soldering each part. Don't wait til the end to test!!! I have learned this lesson the hard way!
- Time to test: Connect separate test leads to the two wires coming out of one side of the focal bead. Connect the other ends of the test leads to the appropriate (+ or -) leg of a prepped LED. Insert a battery into the battery holder and move the switch to the ON position. Ta Da! If the LED illuminates, you are good to go!
- Slide a spacer bead on each pair of wires, sliding it close to the focal bead, and proceed to the next step.
Step 5: Stringing Together the LED-Infused Domed Beads
Now we will work from either side of the focal (battery holder) bead. The images reflect the process from the left side. You will repeat these steps for the other side.
- With one of the bottom bead halves, thread the wires through the hole, making sure the orientation of the bead is correct for the necklace (remember, we placed the holes above the "equator" of the bead so it will sit properly on the finished necklace). Slide the bead-half close to the spacer bead you added earlier.
- Measure the distance needed for one of the insulated wires to reach the appropriate leg of the LED, and strip the silicone sheathing to that point. If necessary, trim the stripped wire so there's about 1" of exposed wire.
- With a new piece of wire, twist the two exposed wires together and solder to the appropriate leg of the LED. (See image) DOUBLE CHECK that you are soldering to the correct leg of the LED. Trim excess wire.
- Repeat steps 2 and 3 for the other leg of the LED. Test by turning on the switch in the battery holder. Ta Da!
- Thread the two new wires through the second hole in the bead half.
- Thread a spacer bead on to the two wires and thread these wires into the hole in a new bead half, checking the orientation as before, testing the connections before and after each soldering session.
- Repeat for the remaining beads on this half of the necklace. On this example, I used two LED beads on each side.
- When you get to the last bead on this half, don't add the new piece of wire before soldering to to the LED. Just solder the positive wire to the positive leg of the LED and the negative wire to the negative leg of the LED.
- Repeat steps 1 through 8 for the other side of the necklace.
- On the last bead on both sides, cut a 12" length of 2mm cording and thread through the open hole. Tie a knot (or two) on the inside of the bead half so the cording will not slip through the hole. Make sure it is small enough for the top piece to fit properly. A drop of Poly Bonder on the knot will ensure that it won't loosen during wear. This knot will be concealed inside the closed bead.
Troubleshooting tip: If the light does not illuminate, go back to the battery holder and ensure that you are carrying the positive wire to the positive leg of the LED, and repeat for the negative wire. If the light still doesn't illuminate, consider that you may have marked the LED's legs incorrectly. All is not lost if you soldered a mistake. I've made this mistake many times and just re-heating the solder joint with the solder iron should disconnect the wire so you can start again. I have also used de-soldering wick to absorb the solder with some success.
Step 6: Closing Up the Beads
Once you have soldered the wires to the LEDs and the electronics are working satisfactorily, it is time to attach the top halves of the beads and adhere permanently.
- IMPORTANT: Remove the battery from the battery holder and set aside. You don't want to heat the battery during this process.
- Match the top halves of the necklace beads (NOT the focal bead with the battery holder) to their bottom halves and "dry fit" to make sure there is a clean connection between the two. You may need to sand the bead edges to ensure a good match.
- If you are using Poly Bonder:
- Apply Poly Bonder sparingly to the edges of one bead half and place on the other half. Poly Bonder is like a super glue, so the bead halves should adhere within a few seconds. Allow to set for at least 10 minutes (or more) before moving the necklace.
- If using Bake and Bond:
- Apply Bake and Bond sparingly, and heat-set the adhesive with the embossing tool. The white adhesive will turn translucent when heated for about 15 seconds. Keep the tool moving - do not overheat or you could scorch the clay. This is a temporary bond and will be fully cured at the end.
- Repeat steps 1 through 4 for all necklace beads (NOT the focal bead with the battery holder - we will get to that later).
- OPTIONAL: Use bits of translucent clay (or a complimentary color of opaque clay) to further seal the bead halves, smoothing the clay to make a seamless connection.
- It's time to fully cure the adhesive and any added clay to the edges of the beads. (This step is optional if you only used Poly Bonder to adhere your bead-halves). Carefully set the completed and sealed necklace on a tile and cure in an oven at the appropriate temperature and time listed on the package of polymer clay. If you used rubber cording, it won't melt in the oven, but I recommend covering the cording with a pot-holder to shield it from direct heat. Allow to cool completely before handling.
- ALSO OPTIONAL: With a small piece of wet-dry sandpaper or nail file, carefully sand the cured edges where you adhered the two bead-halves. You could also buff the beads with a piece of denim. Take care to not wiggle the wires too much during this process. If your soldering is strong, the necklace is quite durable, but you don't want to be careless, as any wire will break if repeatedly bent back and forth.
Step 7: Finishing the Necklace
The battery-holding focal bead needs to have a removable top to enable switching on and off and eventually replacing the battery. I've experimented with a few ideas and the best (so far) is hook-and-loop (Velcro)! While not a common material in the world of fine jewelry, it is a practical material that solves this problem nicely.
- Adhere one small piece of Velcro to the metal part of the battery holder with a thin layer of E6000 glue. Allow to dry completely - at least 12 hours before testing.
- Temporarily attach the other half of the Velcro piece to the inside of the remaining 2" focal bead half with a bit of uncured polymer clay. Put the two halves together and see if the velcro grabs and holds when the two halves are pressed together without gaps. If the Velcro does not grab because the dome is too deep, add additional polymer clay under the Velcro until it attaches to its other half without leaving a gap between the polymer domes. Re-cure the top dome if it was necessary to add additional polymer clay under the Velcro, then glue the Velcro in place and allow to dry completely - another 12 hours before testing.
- Measure the desired length of the cording and attach a clasp to finish the necklace.
- Give it one last buff with a piece of denim, insert the battery, switch on the lights and enjoy.
Step 8: Notes & Tips
- The reason we are positioning the LEDs facing the back half of the bead is to create a more diffused light on the front. The translucent domed LED holder also helps diffuse the light.
- Soldering is easier than you might think. I am a novice but the connections are secure. If this is the first time you've tried soldering, take a look at the many soldering tutorials online and practice a few times to gain confidence before you begin.
- A soldering iron gets HOT and will burn whatever it touches. Keep you work area free of clutter and anything flammable. STAY FOCUSED.
- When soldering the LEDs, DO NOT touch the soldering iron to polymer clay. It will melt it. Keep a steady hand and don't rush.
- You can embellish the removable piece on the battery holder, but try not to add too much weight to it. The hook-and-loop fastener will hold it securely, to a point, but you don't want to risk losing it by making it too heavy for the fastener to hold it in place.
- It is possible to add LEDs to the focal bead. Just solder the positive and negative legs to the appropriate holes on the battery holder, and make the top half of the focal bead with enough translucent clay for the light to show through.
- If desired, glue the battery holder in place on the bottom half of the focal bead. Be careful in the placement so the battery is still easy to remove and replace.
- Instead of buying 24 AWG silicone-covered wire, you could re-purpose old ear-bud headphones and "hack" the wire. The wire just needs to be flexible and insulated so the necklace will hang properly and there are no short circuits.
Troubleshooting Connection Issues
- If the LED did not illuminate, check to be sure the positive and negative connections are correct.
- Check that your battery is fresh and firmly seated in the battery holder.
- Check that your soldered connections are firmly and directly soldered to the battery holder connections. If not, add a touch more solder to reinforce the connection. I haven't tested this, but adding a drop of conductive paintwork each soldering point might reinforce the connection..
- This bears repeating: It is much easier to test your connections frequently and fix mistakes early, than it is to complete the assembly of your project and discover that the lights don't work. You won't have any idea where the mistake happened and troubleshooting will be much more difficult.
Step 9: Variations and New Ideas
Here are some other ideas to consider
- Use differently-shaped hollow beads.
- Make a bracelet instead of a necklace.
- Experiment with warm white versus cool white light and compare the different effects.
- Use red, blue, green, yellow, orange, pink or purple LEDs. Be aware that different colors used together require resistors to ensure the forward voltage is sufficient for all of the LEDs to illuminate. I have found that warm colors (red, orange and yellow) work well together, and cool colors (blue and green and white) work well together without added resistors. Some LEDs come with resistors, like THESE, enabling you to use multiple colors in the necklace without needing to compute Ohm’s Law and soldering on resistors.
- I've tried a "clamshell" design for the bead that holds the battery holder, creating a hinge with a piece of ribbon embedded in the clay. I'm having moderate success and I prefer the ease of use with this design. While I like Velcro, it's not very "professional" looking in jewelry. I've tried magnets too, but learned (the hard way) that they lose their magnetic strength when heated either while curing the clay in the oven, or being too close to the hot embossing tool or soldering iron.