Molding
5 Once the lipstick mass is mixed and free of air, it is ready to be poured into the tube. A variety of machine setups are used, depending on the equipment that the manufacturer has, but high volume batches are generally run through a melter that agitates the lipstick mass and maintains it as a liquid. For smaller, manually run batches, the mass is maintained at the desired mix temperature, with agitation, in a melter controlled by an operator.
6 The melted mass is dispensed into a mold, which consists of the bottom portion of the metal or plastic tube and a shaping portion that fits snugly with the tube. Lipstick is poured "up-side down" so that the bottom of the tube is at the top of the mold. Any excess is scraped from the mold.
7 The lipstick is cooled (automated molds are kept cold; manually produced molds are transferred to a refrigeration unit) and separated from the mold, and the bottom of the tube is sealed. The lipstick then passes through a flaming cabinet (or is flamed by hand) to seal pinholes and improve the finish. The lipstick is visually inspected for air holes, mold separation lines, or blemishes, and is reworked if necessary.
8 For obvious reasons, rework of the lipstick must be limited, demonstrating the importance of the early steps in removing air from the lipstick mass. Lipstick is reworked by hand with a spatula. This can be done in-line, or the tube can be removed from the manufacturing process and reworked.