How to Make a Seashell Mosaic. Some of the most beautiful seashells you pick up on the beach are broken. Don't discard these pieces. Instead use them to make a seashell mosaic. Tile the top of a papier mache box or be more creative and transform an outdoor table. You don't have to make an intricate design so only basic crafting experience is needed. Follow these simple instructions.
Decide on a base color for your project. Consider the hues in the shell pieces and choose one that highlights them best. Seashells tend to have a lot of brown, red, rust, and rose, so brown is a good choice. Pick any color that is appealing to you.
Paint the item with appropriate paint. If you are doing an indoor item, like the paper mache box, acrylic paint is fine. Apply using a sponge brush. Use an outdoor spray paint with rust inhibitor for outdoor items. Allow to dry completely.
Apply the seashells in a pleasing manner to the top of the item using mosaic adhesive. Dry according to manufacturer's instructions.
Follow manufacturer's directions for mixing grout in a disposable container. Grout is available in a variety of colors, allowing you to choose one to complement your masterpiece.
Completely cover the shells with grout using a spatula or your fingers. Press into all cracks and crevices.
Wait about 15 minutes for the grout to dry. Using a damp sponge, lightly wipe away the top layer of grout and begin to uncover the shells. Rinse the sponge and wipe again. Do this process slowly, being careful not to pull the grout out of the crevices. The desired result is a fairly smooth surface with the shells slightly raised.
Clean the grout from around the edges of your mosaic and let dry overnight. Use a soft cloth to buff the shells to a soft sheen.