Set up your work station in an area with plenty of air circulation, such as a kitchen table, garage or workshop. Lay newspapers over your work surface and place the mirror in the center.
Use painter's tape to cover the glass portion of the mirror to protect it from accidental spills and dribbles. Leave the wooden frame exposed.
Paint the wood frame with the base coat, using long strokes that all brush in the same direction. Aim for a smooth, ridge-free coat of paint. Allow the paint to dry for about 20 minutes, then apply a second coat. Let the mirror dry for at least three hours.
Apply the porcelain crackle paint onto the wood frame. Use only one thin coat of paint because a double coat will ruin the crackle patterns. For thinner cracks, apply a very thin coat. For thicker, more defined cracks, apply the porcelain crackle paint thicker. The paint will instantly start to form cracks as it starts to dry.
Remove the painter's tape from the glass part of the mirror. Don't leave it on while you wait for the paint to dry because it may pull paint up with it. Set the mirror in a safe place to dry for about 24 hours.