Kydex is forgiving to work with once you know three numbers: it cuts cold like a hard plastic, it forms at around 300°F, and it is set once it drops below about 150°F. This guide covers the tools and technique for each step, cutting, heating and molding, plus finishing, for anyone making a sheath, a holster, a wallet or a tray.
Cutting
Cold kydex cuts with anything that cuts hard plastic. A band saw is the standard; a jigsaw with a fine blade, a scroll saw, or a Dremel with a cutoff wheel all work. Score-and-snap works on thin sheet for straight cuts. Cut oversize; you will trim after molding. Wear a mask, the dust is unpleasant.
Heating
Three ways:
- Toaster oven at 300 to 330°F for a couple of minutes. Even heat, easy to control, limited to what fits.
- Heat gun, kept moving, until the sheet droops and goes glossy. Good for spot forming and rework, easy to overheat one spot.
- Heat press or sheet heater for production.
The sheet is ready when it is limp and shiny. If it bubbles or smells sharp, it was too hot; that sheet is scrap.
Molding
A foam press is two blocks of dense foam in a hinged frame. Put the object on the bottom foam, lay the hot kydex over it, close and clamp hard, and wait until the kydex is cool to the touch, five to ten minutes. The foam pushes the kydex into every recess, which is what creates the retention lip. For a two-piece, mold each half separately over half the object. For a taco, fold the sheet around the object and press the whole thing.
Trimming and finishing
Trim the molded shell to the outline with the band saw, then sand the edges on a belt sander and round them over. Polish with a buffing wheel if you want. This is the difference between a sheath that rubs and one you forget is there.
Hardware
Drill 1/4-inch holes for eyelets along the seam, set them with an eyelet press, and add screws for retention and a clip. Our belt clip, Tek-Lok and MOLLE clip fit standard eyelet spacing.
Frequently asked questions
What temperature does kydex mold at?
About 300 to 330°F.
Can I mold kydex with a hair dryer?
No. It does not get hot enough. Use a heat gun or oven.
Can I remold kydex?
Yes, once or twice. Reheat and it goes flat again, though detail degrades each time.
How do I finish the edges?
Belt sander, then round over, then buff.
What thickness for a sheath?
.080 inch, the same as a holster.
The bottom line
Cut cold, heat to 300°F, press hard, cool, trim, and finish the edges. Or skip the press and buy a sheath already molded to your tool.
Related reading
How to make a kydex sheath
How to make a kydex holster
What is kydex?
