The durability of a guitar pick is largely dictated by its material – and guitarists today have never had such a wide range of plastic compounds to choose from.
Celluloid revolutionized the guitar pick landscape in the 1920s and 1930s and, while the material remains popular, Tortex, Nylon, Delrin, and Ultem have gained ground.
But the differences between these materials isn’t readily obvious without turning to a technical of the underlying plastic compounds. These modern plastics are far superior to celluloid (which is highly flammable and comparatively brittle) and used to construct bearings, pump and valve parts, gears, medical and scientific instruments, and other parts.
The Acetal plastic compound is used to make Delrin and Tortex picks. Delrin (as well as SUSTARIN and TECAFORM) is simply a brand name of Acetal, which comes in a number of different grades. Tortex is Dunlop’s proprietary treated form of Delrin, which creates a matte surface. Similarly, Ultem is a brand name of the Ultem plastic compound (SUSTAPEI and TECAPEI are also Ultem brands). Ultem is the most expensive of these plastics although I don’t think stock standard Ultex picks are overly expensive (although many branded picks sponsored by high-profile guitarists are made of Ultem and are relatively expensive).
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There are different ways to manufacture these plastics, which changes their properties. For example, extruded nylon 6/6 has a higher tensile strength than cast nylon 6, but is less flexible. Unfortunately, pick manufacturers don’t reveal their exact formulas, but we can compare the broad properties of Nylon, Delrin, and Ultem. Various additives are added to these thermoplastics to reduce sliding wear in the engineering world such as carbon fiber, carbon powder, glass, and graphite.
Ultem is the strongest material according to tensile strength tests (its resistance to being pulled apart), as listed in Table 1 below, which uses data from Curbell Plastics. This should be no surprise to any guitarist that’s used an Ultex pick, but Nylon and Acetal have surprisingly similar properties. Nylon has a slightly higher tensile strength than Delrin but this is different than sliding wear – guitarists know Nylon picks wear more quickly against steel strings than Delrin or Tortex.
Table 1: Guitar pick material strength
| Material | Tensile strength (psi) |
| Ultem (aka Ultex) | 15,200 |
| Nylon (6/6 Extruded) | 10,000-13,500 |
| Acetal (aka Delrin and Tortex) | 9,800-10,000 |
Guitarists also know nylon picks are far more flexible than Delrin and Tortex, but the flexural modulus (or bending stiffness) property shows the difference is relatively slight. Not surprisingly, ultem picks are the least flexible, and Nylon are the most flexible, as shown in Table 2 below.
Table 2: Guitar pick material flexibility
| Material | Flexural modulus (psi) |
| Ultem (aka Ultex) | 480,000 |
| Acetal (aka Delrin and Tortex) | 420,000 |
| Nylon (6/6 extruded) | 410,000 |
There are other factors that influence the durability of picks. Design plays a factor (some picks come with beveled edges and other are flat) although personal technique probably has a larger influence. Some guitarists have a heavy hand which can quickly destroy picks made from softer materials (Wendy Melvoin for instance, prefers Tortex picks for their durability compared to celluloid). Guitarists also need to consider they way pick material and thickness also influences tone.
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