working with kydex?

Joined
Dec 23, 2001
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Does anyone have any good tutorials on building sheaths out of kydex? I would like to add a good one to my favorites for future reference. I want to start using it but have no idea how to use it. Cory
 
Kydex is absurdly easy to work with --- once you've seen it done.

Here's the basics:
Kydex comes in .06 and .09 thickness commonly. Get a piece of both but start with the .06, it's a bit easier to work with.
I use a $25 heat gun, the kind you can get at Wal-Mart for removing paint. You can use your oven if you like but I don't have one in my shop - temp is approx 325 to 350 degrees.

Also from Wal-Mart sporting department, they have a camping mattress pad (maybe $6?). It is a stiff closed cell foam product (not the softer spongy stuff, although I have used that also). Cut 4ea 1'x1' squares. Stack and glue 2ea pieces each to a 1/2" or 3/4" boards. It will look like a big sandwich. Now you have a place to press the kydex. (Many use a large vise or clamps for this -- I simply stand on top of it. I suppose a vise or clamps is more dignified.)

Place a couple layers of masking tape on the blade for clearance in the sheath so it doesn't scratch the blade into and out of the sheath.
Trim the tape to dimensions of the blade. Lumpy tape clumps will show up in the Kydex so make it smooth.

Cut an outline of the sheath in paper the size you need to fold over the knife (or pancake style) -- dont forget a belt loop if you want it. Trace it onto the Kydex and cut that out -- a little oversize please for 'slop'.

Wearing gloves (it gets hot), heat the Kydex until it gets so soft it becomes as pliable as the paper. You might also heat the knife up a little to slow the cooling and hardening of the Kydex it depends on your knife construction - not too hot on the knife though. Quickly wrap the Kydex around the knife, don't forget to pull it tight around the knife, you can poke it a bit to help form around the knife. Ignore the belt loop 'strip' for now, do that later. Then place it (still moving quickly before it cools) in between the foam pads, stand on it for a minute or two, take it out and have a look. (this is for the wrap around style sheath, a pancake style is even easier with two pieces)

You can spot heat heat it and poke it with your fingers to help molding. If you blew it, the beauty is you can heat it back up and start all over. Kydex will try to return to it's original flat shape if heated up again. Very forgiving stuff.

Now and heat and form the belt loop by hand.
Use rivets or chicago screws to close the seams and attach the belt loop to the body of the sheath. Glue doesn't work well. Remove the tape from the blade and try it out. You should have a snap fit with no part of the Kydex touching the blade. You can still use the heat gun to adjust the snap in fit if it is too tight or loose.

I trim off the slop with the band saw and then grind/sand the edges to size.

Once you try it a couple times, it gets quite easy and isn't all that much to simply experiment and learn.
 
Bah. Kydex scraches stuff, gimme a break :)

Sheffields supply sells 3/8" neoprene, get it. Lasts forever, nice tight mold, too. dont get that 1" foam they sell in their catalog, it burns and melts and doesnt get a good mold. Use a heat gun, and gloves are a good idea, i think Allen Blade uses cotton gloves because they dont hold the heat like leather does. I glued the neoprene to some 3/4" pine boards and stick it in a vise and crank it. As for measuring it out, I just eyeball it, and then trim it down to size, kydex is cheap enough :) I used 1/4" eyelets, so paracord or bead chains go thru it easily. Just get an eyelet setter, it helps a lot.

As for scratching the blade, I dunno. I have HP (1500 grit hand finish) blades in kydex sheaths, and havent had one scratch yet. I dont even use tape anymore on the blades. I just use that neoprene stuff, and it don't form tight enough to scratch it. I think one of the probs is that people like those really tight, crisp sheath lines, which means the kydex is RIGHT on the blade, and will cause wear. You can see the outline of the blades on my sheaths, but I dont try to get those really sharp lines, because sometimes, it makes it hard to draw, and reinsert. I'll get some of my kydex sheaths scanned in a day or 2 when i get my scanner set up, and show you what I mean.
 
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