To make decoupage glue, dilute Elmer’s glue with water. In a glass measuring cup, pour in 3/4 cup of Elmer’s white glue. Add 1/4 cup of water, and stir the mixture to combine. Transfer the mixture to a disposable container, such as a paper cup, and then rinse the measuring cup to remove any adhesive residue.
Increase the amount of adhesive mixture by adding any amount of glue as long as you dilute it using one part water to three parts glue. Store any unused decoupage glue in an air-tight container to avoid setting.
To use the homemade glue, clean the object you are decoupaging with a damp cloth. Trace the object onto paper, and cut out a piece to cover the entire surface, or cut smaller strips of paper to layer for a textured look.
Paint a thin layer of the decoupage mixture onto the object, evenly covering the entire surface. Allow the mixture to set for about 20 seconds, and then apply the paper to the surface. Use your hand to smooth the paper, starting from the center and pressing outward to push out any air bubbles.
Allow the adhesive to dry, and then cut away any excess paper on the edges. Coat the paper with another thin layer of adhesive, allow it to dry, and then repeat the process at least two more times.