Blowing can be done in molds in order to create clearly defined shapes and ornamentation. Depending on the desired effect, the blowpipe can turn or remain stationary. Blowing while the pipe is turning is well suited to the fashioning of round shapes, whereas blowing through a stationary pipe is better suited to angular shapes and ornamentation. Molds can be made from various materials: traditional wood molds, molds in metal, aluminum, bronze, (cast iron or steel for industrial purposes), molds in graphite, molds in plaster mixed with silica. According to their material, the molds are used wet and fitted with holes to allow for the escape of vapors.

The mold blowing technique was invented and developed by the Romans who in this way were able to execute flasks of inventive ornamentation featuring floral and geometric designs, or motifs inspired by the human face.