Sand the outside of the broken or cracked area of the chiminea with a medium grit sandpaper. Use light pressure to sand the clay surface until it is smooth. If the outside of the chiminea has been painted, keep sanding until all of the paint has been removed from around the crack or break.
Mix the automotive repair putty according to package directions.
Use a putty knife to apply the automotive repair putty to the cracked or broken part of the chiminea. Apply enough putty that it mounds up slightly on the surface of the clay. If a piece has broken off of the chiminea, use a clamp to clamp the broken piece onto a firm section of the clay before applying the putty.
Allow the putty to dry until it changes to a lighter color and is completely dry to the touch.
Sand the surface of the putty with medium grit sandpaper until the surface of the putty is level with the surface of the chiminea.
Paint the exterior of the chiminea, if desired, using any standard paint followed by a clear top coat of lacquer.