Resin comes in two forms for the home crafter: polyester resin or polyurethane epoxy resin. Both are plastic and often referred to as polyresins. Use polyresins for jewelry, paperweights, magnets and other small craft projects. The glass-like appearance of the harden resin is suitable for embedding objects permanently to make attractive displays.
Choosing a Resin
Polyester resin is perfect for larger projects. Pouring depth must be at least 1/2-inch in order for the resin to cure properly. Use it for paperweights, diorama designs, cabinet pulls or other deeper molds. Polyester resin does not harden on the side exposed to air so a resin spray or sealing agent is necessary to cure the open side of the mold completely. Polyester resin is more susceptible to surrounding humidity and may take up to 3 days to harden completely. It is more forgiving than epoxy resins---a sealing agent will cover any small blemishes in the finished item.
Epoxy or polyurethane resins are most often used for jewelry and other projects requiring a depth of less than ½ inch. Epoxy cures to a rock hard finish throughout within 24 to 36 hours at room temperature. It is well suited to coating and sealing objects, such as tabletops or the surface of pendants. It doesn't emit the strong fumes like polyester resins do. Both types of resins are available at craft stores.
Purchased resin molds work with all types of resin as long the depth is correct. Made of lightweight plastics molds come in a variety of sizes and shapes. Substitute silicone and rubber molds, such as ice cube tray or baking pans, for store-bought resin molds. Use plastic food storage or other containers with polyester resin. Making your own molds with latex or silicone is another possibility. Always use a mold release spray if the mold is not specifically made for resin crafts.
Instead of a mold fill objects permanently with resin. Bottle cap and mint or candy tin dioramas are two options. Lockets and jewelry bezels work if there are no gaps between the frame and backing for the resin to leak from. Place a thin coat of epoxy resins on top of metal or wooden shapes or objects to add a glass-like seal.
Polyresin is valued most for embedding work. Any object can be embedded and sealed within resin. Non-porous items need no preparation before embedding. Plastic and metal charms, shells and beads are examples of non-porous objects.
Porous objects include paper, dried flowers and fabric. Seal porous objects before embedding with decoupage glue or a spray sealant. Let dry completely before using.
Fill your mold halfway and let the resin cure for 30 minutes to 1 hour. Place the object inside the mold then continue filling the mold to the top. Let cure for the specified time. For flat or sealed projects attach the embedding object to the base with decoupage glue and let dry. Spread a thin coat of resin on top and let cure.