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Kydex equipment projects

 ·  ☕ 8 min read  ·  ✍️ Cj


It’s been some time since I did any kydex work, and way back when I mostly just did knife sheaths. Well I’ve decided the thing that would really make my G21 more useful would be to make it a better holster, as well as some new magazine pouches to go with it.

For those of you who don’t know, kydex is this really cool thermoforming plastic that can be heated to just under 200 degrees, where it becomes flexible enough to mold around parts almost like really thick plastic wrap. Then when it cools it becomes a rigid sheet again. It’s a trade name for acrylic-polyvinyl chloride, and is manufactured under several names such as Kydex, Bolteron, Holsteron, and others. Originally developed for aircraft parts, it has seen huge use in the manufacture of knife and tool sheaths, and holsters.

The tooling

press layout
The tooling I use to form the kydex is pretty simple. A heat gun and toaster oven to keep the kydex at ~180degrees, a kydex press, and one bit of tooling I made myself. Beyond that, a scroll-saw for cutting the excess plastic off after forming and a belt sander for cleaning up the edges.

Rivet setter:

Two layers of kydex are attached with hollow rivets, and one end flared over to fix it in place. I’ve tried this with a hand tool and a hammer, and it usually splits the rivet, and is hard to get evenly rounded down. So I made a tool for the arbor press that does it for me. The mandrel portion does the flaring, the other side just supports the already-rounded side of the rivet.
rivet setter

Using the rivet setter

First, the rivet goes through the kydex and on to the mandrel like so:

rivet on setter

gently squeeze together in arbor press:

arbor pressing

Now the kydex is permanently fused together:

pressed rivet

G21 double mag pouch

double mag pouch
My goodness did this one cause some frustration. It was a real trick getting all the parts to stay together and not slide all around while moving my hand to close the press. The magazines got taped together with a narrower block of wood between them. This spaced them where I wanted and made for at least 1 less moving piece. If you’re going to make something like this, use way more kydex than you think, and plan on cutting all the way around to the shape and height you want. Trying to keep the kydex lined up with where I wanted the top to be was most frustrating.

.308 and 5.56 mag pouch

.308 mag pouch, front and back:

308 pouch front
308 pouch back
The mags are taped up with a thin strap of wood along the top of the kydex. This makes it a little wider and provides a sort of ‘mag-well’ to get the mag back in easier. Below that on the other side is another wood piece that will be the pocket for the mounting screws to fit into.

Both sizes are pretty much the same, just the magazines are different

AR mag pouch. Holds 30 and 20rd magazines equally well:

ar mag pouch
I was a little undecided on how to mount these, so I made up a couple basic belt loops to try. I wanted something removable, as I might change belt size or mounting type. I think I’ll make a larger mounting area on the next ones, as this one is rather limited in how high or low on the belt it can be adjusted.

belt loop close up:

ar mag rear

Relief for mounting screws, made by taping a piece of thin plywood to the magazine:

mounting plate

Adjustable retention on the mag pouches and holsters are provided by these rubber bushings:


G21 holster, my toughest kydex project so far

I was surprised to find rather a lack of Glock 21 holsters on the market. There were a few, but nothing quite seemed to be what I needed. My needs were rather specific however:

  • Paddle mount- A full size handgun is rarely ‘all day comfortable’, especially when standing, sitting, on the couch, etc. A paddle holster solves that by being easy to take off and put in a desk drawer, and don again when standing up.
  • Taco style- I’ve only tried on so-called ‘pancake’ holsters a few times and didn’t like them a bit. This is when two separate pieces of kydex are sandwiched over the handgun and rivets run down either side. The result is the single bulkiest holster design you’ve ever seen. I found them ranging from uncomfortable, to just annoying. ‘Taco’ style is the folding over of a single piece of kydex. This makes a more compact package, and easy tension adjustment by squeezing the open side together with screws. It does seem to be more difficult to make however.
  • Forward cant- Even when wearing at the 3 o’clock position, tilting the grip slightly forward makes it much easier to get into a front pocket. When wearing it further back it’s an easier draw, and very similar to several other leather holsters I’ve used extensively. Of the two forward cant G21 paddle holsters I found online, only one had the steeper forward angle I wanted.
  • Coyote tan- Because black is getting boring.

Keep in mind this isn’t necessarily what makes a ‘best’ holster. This is just what’s best for me, and what I find most useful.

Getting started

First thing I did was trace the Glock slide, then roll it around the paper and sketch a holster around it. I could then fold the paper around the gun and see about what size and shape my kydex sheet needed to be cut to. Keeping in mind to leave a lot of extra margin around the edges anyway.

the pattern:

paper pattern
Then it’s time to start ‘blocking out’ the gun, as I like to call it. In this example, I’ve got a pencil taped to the top to keep a channel clear through which the front sight can move, a large popsicle stick will space the sweat guard a little further away from the slide. Not shown is a block of wood I sized slightly thinner than the trigger guard, so the area with the retention screws stays parallel on each side and leaves room for the rubber washers.
blocking out
I didn’t get much in-progress pictures in this next part, as it took most of my hands and brain power to figure out what I was doing. What I ended up with was trying this twice.

The first try is on the bottom, second try is on the top:

first and second holster
Quite an improvement isn’t it? I learned a couple important things here, namely how important it is to preheat everything. The instant room-temperature foam touches the kydex it starts to cool, and the first problem it creates is it starts to become stiff while you try to wrestle the press together and hold two layers of Kydex and the object being molded. Second, even though it functions fine, it doesn’t get that crisp definition that you see on Kydex that has been professionally vacuum-formed. Foam-pressing kydex will never get quite the same level of definition, but as you can see above preheating the foam is a huge improvement in how everything looks.

Beyond that, I also learned that my original design sat too low on the waistband, also the sweat-guard area just wasn’t stiff enough for the paddle. I added a small piece of plywood and pressed it again to flare the edges a bit, but the bend right above the top of the holster still moved enough I wondered if this would be a weak point after some use.

A working holster:

holster front
holster back
So here it is formed, cut, sanded, drilled, and with all it’s hardware attached. It’s a little long on the front- I couldn’t decide if I wanted some closure to prevent dirt intrusion, or just cut it off flush with the muzzle. I’m going to use it as-is for now and decide later if it needs further sanding.

Retention is excellent, cant angle is just where I wanted it. Second try is total success:

complete holster

In conclusion, some tips I found along the way

  1. Preheat everything. I had this handy heatlamp to warm the press and fixture parts under while I heated the kydex with a heatgun. This gave way better definition as the kydex could form better before cooling down; which couldn’t happen if it hit cold foam right away.
  2. Rehearse your movements a little bit. Pretend you’ve just picked up the hot yet cooling kydex sheet, fold it , fit it in the press and squeeze everything together. You’ll usually find some tool, fitting block, clamp, etc. that wasn’t in reach. Now your kydex is out of position and cooling off by the time you step away to get it.
  3. Block out deep gaps, like the ejection ports. It doesn’t help with retention, but it does pretty much lock the gun permanently in the holster. I had to loosen it up and press it out by gently warming the area with the heat gun. Next time I’ll fit a piece of wood or foam in the gap instead.
  4. If you’re going to do a lot of this, Forstner drill bits and Brad-point drill bits (usually marketed for furniture making) cut very clean, very round holes in plastic. A perfect size for rivets and unlikely to snag and twist the work out of your hands like some twist drills will.
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