Selecting Your Pendant
Find a pendant that speaks to you. You want one that's around 1.5 x 2 inches in size, with holes in it so the lights can get through. A bigger pendant is better! If it's too small, the electronics will show around the edges.
It's best to find one that has a concave open area inside. We'll be making the electronics as small and flat as possible, but a scooped out pendant like this turtle will give you a little more space to work with.
Or, you can download & print or order one of these 3D-printed pendants which are just the right size and shape. Order in metal to be super fancy! Or order him in white or colored plastic and paint him with shiny spray paint or enamel.
Knead a little ball of polymer clay until it's soft, then press it into the back of the pendant. You want a very thin layer -- as thin as you can get it without compromising stability. Work it gently into place, then hold it up to the light to be sure it will work as a light diffuser, and not as a light blocker.
For this Sculpey glow-in-the-dark clay, I baked my little turtle at 275 degrees for 10 minutes. Read the directions, every kind of clay is a little different.
If you're using a 3D Printed pastic pendant, this will still work. The polymer clay wants a pretty low temperature. Don't worry.. you won't melt him!