KYDEX® Knife Sheaths – What is KYDEX? Why’s it so popular?

June 29, 2015

by Inside Heinnie Haynes

What is KYDEX?

KYDEX is a line of thermoplastic acrylic-polyvinyl chloride materials manufactured by a company called Sekisui SPI  who also own the ALLEN Thermoplastics brand. KYDEX is a world renowned brand name, with its uses spanning a huge range of industries, for a wide variety of uses. Among them are sheaths and holsters for knives and guns.

The beginning

KYDEX was originally the masterpiece of Rohm and Haas Company, a Philadelphia-based materials manufacturer working in the aircraft interior business. It was in the the late 1960’s that people started realising the possibilities that KYDEX offered. They realised that the sheets could be moulded and manipulated into a massive range of shapes, by simply heating and moulding around forms. The brand KYDEX has since changed ownership a few times, but the brand itself has still managed to become almost a household name for moulded plastics.

You can find more information about Sekisui-SPI the company who owns KYDEX here:

Why is KYDEX so popular for knife sheaths?

There are so many reasons why KYDEX is so popular.

It has the following advantages:

  • WaterproofKYDEX<sup>®</sup> Thermoplastics - Knife Sheath Image
  • Scratch resistant (Rockwell “R” hardness of 90)
  • Holds its shape and will not alter unless forced under
    certain conditions
  • Low maintenance
  • Able to simply wipe clean

Usually as the knife is re-inserted into the sheath, you will hear a ‘click’ sound which helps you know your knife is safety secured.

Some companies are going one step further than just using normal KYDEX Sheaths. These improved sheaths will be designed to be extra quiet with minimal rattle, they will contain rub strips to minimise wear of the knife and its coating and contain weep holes for water drainage among other things.

Are all KYDEX sheaths the same quality?

Much like any other manufacturing materials, there are differentKYDEX<sup>®</sup> Thermoplastics - Knife Sheath Image 3
grades of thermoplastic. KYDEX manufactures over 40 different lines of thermoplastic sheets, each with its own properties and price point, from budget to premium ranges and everything in between. See the KYDEX website for the full details about each sheet variation.

Be aware though, not every sheath you buy that calls itself KYDEX is KYDEX. As you can imagine with any company that produces such a world known product, there are copycats. For example, there are no injection-moulded holsters made with genuine KYDEX-brand plastic! That’s because KYDEX is engineered from pure polymers; their extruded sheets don’t contain blended stiffeners (such as glass). KYDEX lasts longer than cheaper plastic and it’s far less likely to damage your knife, no matter how many times you remove and re-place it in the sheath.

To create a genuine KYDEX sheath, makers heat a sheet of plastic, mould it around a form, cut off the excess material and polish the finished article. It’s a slower, more labour-intensive process that requires considerable expertise and quality control. For example, the KYDEX has to be heated to a precise temperature and cooled properly.

Let’s Summarise

A moulded KYDEX sheath is a hand-crafted product. It’s a difference that’s reflected in both performance and the price. You get what you pay for not only in quality of the material, the durability of the product and the considerable time it’s taken to produce, but also in the knowledge that you knife is safe and secure in a sheath that’s designed to protect and serve.

Reprinted with permission from Lorax Ltd. Click here to view the original post online.

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