Kydex: material for knife handles and sheaths

Kydex is a revolutionary thermoplastic material known for its durability, versatility, and ease of molding. Widely used in the creation of custom holsters, knife sheaths, and various DIY projects, Kydex has become the go-to choice for professionals and hobbyists alike. Its unique blend of rigidity and flexibility allows for precise shaping, ensuring a snug fit for any item. Resistant to water, scratches, and most chemicals, Kydex guarantees longevity and protection. Whether you’re crafting a custom carry solution or a protective covering, Kydex delivers unmatched performance every time.

Kydex is popular among leading US knife manufacturers. However, since it’s an expensive material, it’s mainly used for premium models. It’s also very popular for making holsters for pistols and revolvers.

What is Kydex?

Kydex is a sheet thermoplastic material made from an acrylic-polyvinyl chloride alloy, invented in the USA in 1965 by Rohm and Haas for use in aircraft interiors. In 1987, the product line was acquired by Kydex, LLC, formerly Kleerdex Company, LLC.

The material combines the positive properties of acrylic, which provides rigidity and moldability, with those of polyvinyl chloride, known for its unmatched strength and resistance to external chemical and mechanical influences.

Though Kydex might feel somewhat like soft plastic to the touch, it’s a completely different material, renowned for its extreme durability and strength. The slight flexibility of the Kydex used in Kizlyar Supreme sheaths allows them to be designed in such a way that no mechanisms or fasteners are needed to secure the knife inside. The sheaths expand when the knife is inserted and immediately return to their thermoformed shape tailored to the knife.

Kydex’s unparalleled durability ensures that the sheath will never fail you – it won’t get cut, break, swell, or rot. Compared to regular plastic, it’s much more flexible and cannot be broken; it merely bends and then returns to its original shape.

Kydex has high volume stability, doesn’t change size with environmental changes, doesn’t absorb moisture, is fire-resistant, and is easy to clean. It has a slightly rough surface, which protects the sheath from minor scratches and reduces slipping.

Kydex characteristics

It is an acrylic-polyvinyl chloride composite designed for thermoforming and combines the properties of both acrylic and polyvinyl chloride components. From acrylic it obtains stiffness and formability; from PVC strength, chemical resistance and good internal strength ratings.Sheet thickness ranges from 0.74 to 12.70 mm and can be thermoformed into a variety of shapes.

  • The flexural modulus is 2800 MPa.
  • The molded sheets have good hardness and resistance to deformation. This is especially important for intricately molded parts with thin walls.
  • Relatively hard thermoplastic. This hardness, combined with a granular surface, increases its resistance to abrasion.
  • Low flammability, UL 94 V – 0 classification

For some applications it is used as a replacement for leather where it has the following advantages:

  • Waterproof
  • Scratch resistant
  • Holds its shape better, does not stretch or shrink under normal conditions
  • Has a low coefficient of friction

The Kydex manufactured in the USA, boasts some unique characteristics:

  • High strength (hardness of 94-111 Rockwell R units)
  • High impact resistance (961 J/m)
  • High elasticity parameters (2,482 MPa, 360,000 psi)
  • High fire resistance (stable up to 78°C molding temperature)
  • High resistance to abrasive impacts, such as scratches
  • High chemical resistance
  • High volume stability, doesn’t change size with environmental changes
  • Doesn’t absorb moisture
  • Slightly rough surface, pore-free

Kydex sheaths typically feature numerous evenly spaced holes. These holes offer unmatched flexibility in attaching the knife almost anywhere and in any position. You can attach a rotating clip and hang the knife horizontally behind your back or vertically in a traditional manner. It can be worn around the neck, tied anywhere, or attached to any load-bearing system, whether on the shoulder or under the arm.

Kydex types and colors

Kydex is available in various colors and is used in many industries, such as military, aerospace, aviation, automotive, medical, and others. Common examples include many aircraft and car components, especially seats, which are made from Kydex due to its fire resistance, durability, and excellent strength characteristics.

What the Kydex is Good For?

  1. For DIY Projects: Kydex Thermoform Sheet is a versatile material that closely resembles other thermoform materials like Holstex and Boltaron. When heated, it can be molded around objects, retaining its shape once cooled. This lightweight and durable material is a top choice for creating holsters, cosplay costumes, protective coverings, keel guards, and more.
  2. Surface Texture: The Kydex sheet features a P1 “Hair Cell” texture, a reference to its grain’s size and appearance. This texture is prevalent in many Kydex products available in the market. P1 is the preferred texture for items like holsters and sheaths due to its consistent, non-reflective, and scratch-resistant finish.
  3. User-Friendly: Working with Kydex is straightforward. First, cut a piece slightly bigger than the intended object. Heat it between 300-375 degrees Fahrenheit, then mold it over the object. Using forming foam can help in shaping the material. Once cooled, trim and sand the edges for a perfect finish. (A detailed guide is provided with the purchase.)
  4. American Craftsmanship: Proudly manufactured in the U.S.A., each Kydex P1 textured thermoform sheet undergoes individual inspection by our dedicated team. We are committed to delivering top-quality products and stand by every item we sell. Buy with trust!
  5. Unmatched Quality Assurance: With over two decades in the holster accessory market, HolsterSmith’s thermoform sheet materials are second to none. Trusted by professionals, including soldiers, law enforcement, and public safety personnel, our sheets are globally recognized for their quality. Every sheet undergoes rigorous inspection, ensuring you receive the best product.

How much is Kydex?

The cost of Kydex can vary based on factors such as thickness, color, texture, and the specific retailer. Typically, Kydex is sold in sheets, but it can also be found in smaller pre-cut pieces for specific projects. The price can range from $10 to $50 or more per sheet, depending on the size and type.

Kydex sheets can be purchased from:

  1. Specialized Online Retailers: Websites that focus on materials for holster-making, knife sheaths, and DIY projects often carry Kydex. Examples include and
  2. General Online Marketplaces: Websites like Amazon, eBay, and others might have Kydex sheets available from various sellers.
  3. Local Plastic Supply Stores: Some local stores specializing in plastics might carry Kydex or can order it for you.
  4. Craft and Hobby Stores: Some larger craft stores might carry Kydex, especially those that cater to more specialized crafting hobbies.

If you’re looking for the most up-to-date pricing and availability, I’d recommend checking online retailers or contacting local suppliers directly. Always ensure you’re purchasing genuine Kydex, as there are other thermoforming plastics that might be similar but not have the same properties.

Kydex disadvantages

While Kydex has many advantages, it also has some drawbacks:

  1. Brittleness in Cold Weather: Kydex can become more brittle in extremely cold conditions, which might increase the risk of cracking or breaking if subjected to strong impacts.
  2. Cost: Kydex is generally more expensive than some other thermoplastics or traditional materials like leather.
  3. Aesthetic Limitations: Some people prefer the natural look and feel of materials like leather over the synthetic appearance of Kydex.
  4. Wear on Contents: Over time, the hard nature of Kydex can wear on the finish of items it holds, such as the slide of a firearm.
  5. Limited Self-Repair: Unlike leather, which can sometimes be conditioned or repaired if scratched or damaged, Kydex does not have self-healing properties. Deep scratches or gouges in Kydex are permanent.
  6. Thermal Sensitivity: While Kydex is a thermoplastic designed to be molded when heated, this also means it can potentially warp if left in extremely hot environments, like the inside of a car on a hot day.
  7. Rigidity: Its rigidity, while a strength in many applications, can be a limitation if flexibility is desired.
  8. Sound: Kydex can be noisier than other materials. When a firearm or knife is holstered or unholstered, for example, it might produce a distinctive “click” sound.
  9. Weight: While Kydex is lightweight, it can be heavier than other holster materials like nylon.

It’s essential to weigh these drawbacks against Kydex’s benefits when considering it for specific applications.

Kydex itself is not used to make knife blades; instead, it’s a popular material for making knife sheaths. The thermoplastic nature of Kydex allows for a tight, custom fit to the specific knife model, ensuring that the knife is held securely in place.

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