Fimo™ is a leading brand of polymer craft clay, designed to be hardened in a conventional oven. Popular for use in small models and jewellery pieces, many craft makers like to incorporate objects, such as rhinestones or crystals, into their works of art. Though it's simple to press a crystal into clay and bake it (since a low-temp conventional oven won't damage glass or semi-precious stones), getting the crystals to look their best requires a few additional steps for positioning and shine.
Soften the Fimo by working it in your hands, using both the warmth of your hands and pressure to soften it until it's smooth and pliable. If necessary, rub a small amount of mineral oil on your fingers to help soften the clay if it's too crumbly (Fimo is a harder formula when compared to other brands of polymer clay).
Build the sculpture or shape you want the crystals set in; make it as complete as possible so that further manipulation of the clay won't disrupt the placement of the stones. Press the areas where you want to place the stones so that they're relatively flat.
Make impressions for the crystals in the soft clay. Hold the crystal just above the portion of the clay sculpture where you want it to gauge the positioning before pressing it slowly into place. Press the crystal down until it's submerged in clay to the depth you want, wiggling the stone very slightly so that the impression will be a little larger than the crystal. Tip the clay piece on its side to drop the crystal out (assist with a pin, if necessary), leaving an impression in the shape of the crystal.
Repeat step 4 with all other crystals you want to place in the sculpture.
Clean the crystals with a cotton swab soaked in a solution of water with a little dish soap; this will remove oil smudges from your hands and from the clay. Set aside.
Bake the clay according to the manufacturer's instructions. Let cool.
Paint the insides of the crystal impressions using silver paint and the detail brush; this will provide a backing for the crystals to shine and keep them from disappearing into the sculpture.
Glue the crystals into the impressions. Use the toothpick to place a tiny drop of clear glue into the centre of each impressing, then set the crystal in place using the needle-nosed pliers. Let dry.