Sand and paint the plywood trivet base. Let the paint dry for 3 hours.
Remove the curved edge of the dishes with the tile nippers. Place the flat portion of one dish in a pizza box and close the cover of the box. Break the dish into small pieces with the hammer. Repeat with the remaining dishes.
Glue the broken dish pieces on the plywood trivet in a random pattern. Let the glue dry for 3 hours.
Mix the ceramic tile grout with water according to the grout manufacturer’s directions. Spread the grout over all spaces between the broken dish pieces with the craft stick to create as smooth a surface as possible.
Immerse the sponge in water and wring it out. Remove any excess grout with the damp sponge. Let the grout dry for 24 hours.
Spray the grout sealant over the completed decorated trivet. Let the sealant dry for 24 hours.
Use epoxy glue to attach four evenly spaced marbles around the inside edge of the bottom of the trivet. Let the glue dry for 24 hours.