Kydex – Close Encounters of the First Kind

It’s hard to imagine all the materials used to sheath knives. I can imagine a by-gone craftsman carefully fitting pieces of wood to create a protective pocket around an edge. He had a few different options on how to bind the two sides together. Plant fibers or hair could be twisted to create cord and then wrapped around the two sides of a wood sheath. The discovery of glue opens up many possibilities: glue the two wood halves together or use it to create build-up layers around the sheath. I’m sure glued impregnated paper or cloth was the micarta of the day.

Animal skin is an obvious solution. It could be sewn with other animal parts even as we speak of using cat gut or deer tendons today. It could also be decorative. I can see my fixed blades with a coyote or skunk fur sheath, especial with the skunk’s white stripe. It says something about the man carrying a blade in a black and white fur sheath. What, I don’t know, but it says something.

Once we learned how to tan hide, leather became even more useful. We still value leather as a sheath material. I have friends who carry Ka-Bar fighting knives while hunting. They want the silence of leather in the bush.

Metal seems to have been reserved for sword and other thin blades. Many art knives sport thin metal sheaths, but few of us would carry an art knife out on a picnic much less to a caribou hunt in Alaska. They seem to have fallen out of fashion. I don’t know of any factory produced fixed blade knife in a metal sheath. Is it weight? Maybe it’s concern about corrosion? Or are we just worried about dulling the edge every time the knife goes in or out of the sheath?

Kydex seems to be the answer. Wears like iron, isn’t harmed by moisture and sweat like leather and it doesn’t corrode the metal. It can be a little noisy in the field. In an urban environment the background noise out weighs the little ‘zith’ the blade makes slipping from the Kydex.
Since it’s moldable at low temperatures everyone with an old toaster oven or heat gun is trying their hand at it. YouTube is filled with how-to videos to initiate you into the secret brotherhood of Kydex workers. Why shouldn’t I be included in this group?


So I bought foam to make a press, bought Kydex, Chicago screws, leather working rivets, plywood to hold the foam. I already have a heat gun, an old toaster oven, an assortment of clamps, hammers, metal straight edges and drill bits. The sky’s the limit. My first target is an original Blackjack fixed blade I found at a gun show. It cleaned up nice and is very collectable, but I want that poor man’s Randall for my days in the woods.

I cut the Kydex to the size I wanted and with a heat gun folded the plastic sheath and pressed it flat. Hmmm. I didn’t get the flat fold Murray Carter shows in his video.

I reheated the folded Kydex and the crease goes away! It’s now cooked-noodle flexible and I’m trying to the position the knife and the floppy Kydex in my foam press. I found stiff thick foam, but not the high density foam recommended. I’m hoping that a nine and a half inch thick foam press will compress enough to flatten the foam and shape the Kydex. It’s harder than it looks.

I stand on the press and my body weight proves to have enough force to compress the foam. Unfortunately it’s very hard to apply the large wooden handscrew clamps from that position. What am I going to do?
About that time my wife sticks her head out the door and enters the Kydex fray.

“Well, got any fruits of your labor yet?” she says.

“Say,” I said, “why don’t you give me a hand.”


I quickly move the press to the plywood and saw horse work table I have set up in my summer workshop, AKA: driveway. I had the wooden screw clamps and while she’s opening the jaws, I press down on the press only to have the plywood teeter-totter up on me. She reverses course, pushes the table down and I reposition the press.


The first clamp goes on without too much trouble. We’re both conscious of the Kydex cooling off in the foam press. I pick up the press, do my imitation of Hercules crushing a phone book and she slaps the clamp on the press and my finger.

Before I can say anything she starts tightening the clamp.


“Not my finger… Not my FINGER… NOT MY FINGER!”   This seems to be the only intelligent thing I can say.

“Oops…Sorry!”

That crises out of the way, we get the press closed and let it cool. Twenty minuets later the press comes open, and I understand how a baker feels when his cake fails to rise. The fold in the Kydex has bulged, the knife is at an angle to the sheath and the Kydex has parallel lines embossed into the surface. Oh…from the toaster oven grill. And I don’t know how I’m going to attach this sheath to a belt.

Still I’m encouraged. Easier than wood working and it doesn’t have the odor that skinned skunk pelt has. More on this project later!