What is a space-age composite doing in a wooden musical instrument? It’s simple, really: protecting against deformation in the wood due to changes in temperature and humidity. Guitar makers, also known as luthiers, have figured out that adding carbon rods to the neck of a guitar prevents it from warping when conditions get hot or wet, dry or cold. While wood is a dynamic substance, carbon composites are extremely stable.
Early guitar necks were made entirely of wood; however, wood is responsive to temperature and humidity. In the early 20th century, these all-wood guitar necks would warp and deform in uncontrollable ways, which would then change the height of the strings and relief of the neck.
The addition of steel truss rods to guitar necks in 1921 allowed guitar players to adjust the relief of the neck as environmental conditions changed. Carbon fiber reinforcement alongside the steel truss rods adds even greater stability to the wood by minimizing the effects of environmental changes.
Carbon composite rods and tubes are ideal materials when considering structural reinforcement.
Carbon fiber composites are between 2 and 10 times more rigid than steel and aluminum for a given weight, depending on the orientation of the carbon fibers within the composite and the orientation of the stress. Uni-directional carbon rods and tubes, in which all carbon fibers are linearly oriented, are extremely strong in one direction. Wrapped composite tubes can be made with incredible hoop strength at super low weight to resist crushing or impact.
Because carbon fiber composites keep their mechanical properties under dynamic loads, rather than deteriorating over time, they make great structural components in systems with active, repeated stresses. Carbon composites perform well in acidic, basic, or otherwise chemically challenging environments. Additives in the resin can enhance resistance to corrosion or UV radiation deterioration.
And there’s more: carbon composites are also unbelievably customizable.
The process to create the composite product, including pultrusion, roll-wrapping, bladder molding, press molding, vacuum bagging, infusion, and so many more, will determine some of the properties of the final product. So, too, will the raw materials used. For instance, a rollwrapped tube could be made using carbon fiber prepreg (cloth pre-impregnated with resin), fiberglass prepreg, or a combination of those or many other materials with a variety of resins. The fabric might be woven or unidirectional and can be cut with or against the fiber direction and layered during the manufacturing process to create differences inflexibility, hoop strength, impact resistance, and wall thickness. The mandrel can be of any diameter and could be tapered or straight. Changes to the curing temperature, length of cure, and the compression tape wrap can also affect the outcome. After curing, a tube can be ground to a specific diameter, sanded for a bonding surface, notched, drilled, or milled to specification. Options are literally endless.
If you’re designing a product with a steel, wood, aluminum, or plastic support piece, consider instead using a composite rod or tube.
Goodwinds Composites can manufacture rods and tubes to your exact specifications. The company offers a wide variety of small diameter composite rods and tubes off-the-shelf for fast prototyping and can design and manufacture custom rods and tubes relatively quickly. Visit www.goodwinds.com for more information on all Goodwinds Composites processes and capabilities, as well as technical information about composite products.
Goodwinds Composites manufactures composite rods and tubes for a variety of industries. They helped design and wholly manufactured the landing gear for NASA’s Mars helicopter, set to launch in 2020.