First, you’ll want to smooth any rough spots on the surface of your plywood using sandpaper, and then wipe the dust off with an old cloth. Seal the front surface of the plywood with two coats of white paint before starting your project. You can use primer or acrylic craft paint with a foam craft brush and allow the first coat to dry completely before applying the second coat.
After the paint is dry, start filling in the spaces with bottle caps to create your butterfly mosaic. Once you have an arrangement that you’re pleased with, adhere the bottle caps one by one to the plywood using E-6000 (in a well ventilated area) or a hot-glue gun.
As you can see, many bottle caps come with printing on the underside of the label, or the underside is grey or light blue even though the cap may a completely different color