Fiberglass is durable, long-lasting and lightweight, making it a suitable choice for garden pots and planters. To make a fiberglass planter, you need a metal mold or an actual planter in your desired size around which you can lay the mats. The material is left to harden so it takes the shape and size of the mold, thus forming an exact copy. Fiberglass is available in marine or auto parts stores and is easy to work with. Use fiberglass planters to dress up a balcony, terrace or spot where weight is a consideration.
Wipe the inner and outer surface of the desired mold or planter with a cloth and leave to dry. Smooth out any bumps on the outer surface of the mold to give it an even finish. Cut 2-by-4 lumber to four 6-inch lengths using a saw.
Glue a 6-inch length to each inner corner of the desired mold or planter using a hot-glue gun and glue sticks. The lengths of wood serve as legs that lift the mold off the ground so the outer surface is easily accessible.
Apply two to three coats of mold wax over the outer walls of the mold using a foam applicator and leave it to dry. Use a clean rag to wipe away excess wax from the mold.
Measure the length and width of the base and outer walls of the mold and cut fiberglass mat to size using a razor knife. Using the cut mats as a guide for the remaining three layers, cut more mats so you cover the outer walls of the mold four times.
Follow label directions for mixing the resin and catalyst in a small bucket. Run a felt roller covered with resin over the outer walls of the mold to wet them. Apply the first layer of mats over the wet surface and completely saturate these with the prepared resin mixture using a roller. Make sure the seams at the edges do not overlap and trim the excess with a razor knife before saturating.
Run an air roller over the surface gently to flatten the mat and remove trapped air bubbles to give the planter wall an even finish. Repeat the procedure for applying each layer of mat over the previous layer and saturating it completely with resin until you lay all four layers. Leave the fiberglass in a cool, shaded spot for four to six hours or until dry.
Rub the surface of the dried fiberglass using 100-grit sandpaper gently to remove rough spots and give the walls and base an even and smooth finish. Also sand the edges at the opening of the mold.
Slide a metal scraper between the mold and fiberglass and run it between the surfaces to loosen the fiberglass. Insert your free hand inside the mold and lightly tap the inner base of the mold to release the fiberglass. Slide the fiberglass out of the mold.