As with all things pipes there are many different options and preferences when it comes to stem material. Many materials have been used over the years including horn, bakelite, amber, and others but the most common materials are ebonite/vulcanite and acrylic. Ebonite, or vulcanite, is hardened (vulcanized) rubber and has been popular for many decades because it is a bit softer than other stem materials making it more comfortable on the teeth. Ebonite is particularly popular as a stem material for high grade handmade pipes. The drawback to ebonite is that over time it oxidizes, losing its shine and typically changing color to a brown/green that is distinctly less nice looking than its freshly polished form. Often, an oxidized ebonite stem can be brought back to it's former glory but that takes a decent bit of work and can only be done so many times before issues arise. In contrast, acrylic is quite a bit harder and while many consider it a less comfortable material, it is more durable, doesn't oxidize like ebonite, and comes in an even wider variety of colors/designs. Acrylic and ebonite stems can be made from solid block or rod or through injection molding. Stems milled from acrylic and ebonite block or rod stock tend to be harder and more durable than those made using injection molding.
BriarWorks and Moonshine pipes all feature acrylic stems milled from solid stock. This material polishes to a nice shine and doesn't oxidize so our customers don't have to worry as much about biting through a stem or dealing with unpleasant oxidation over time. That's not to say that ebonite isn't a great material for stems and that acrylic doesn't present some challenges. For instance, ebonite requires less heat to become pliable so it is easier to bend than acrylic. Acrylic doesn't get soft enough to bend until it is heated to over 300 degrees Fahrenheit. All BriarWorks and Moonshine stems start out straight. For bent shapes we heat and bend each stem individually. That's a good deal of extra work and one might ask why we go to the trouble. We go to the trouble because because we think the material provides the best balance of durability, comfort, engineering, and aesthetics in a factory production setting. All of us at BriarWorks that make handmade pipes with hand cut stems primarily use ebonite for those pipes. Factory production, however, requires a different balance of comfort and durability as we cater to a larger audience of pipe smokers and collectors, many of which don't want to deal with the extra maintenance and care required for ebonite. We think our stem designs strike a nice balance of durability, comfort, and internal engineering and help make a great smoking pipe that will last many, many years.