Forming Kydex

[Bill Harsey]

This thread is about forming kydex.
I'm not sure where to start so here is the first simple thing I thought of to try and make things easier.
When one is forming kydex in a press around a blade, there has to be some relief between the blade and the Kydex or else the blade will pinch going in and out of the finished sheath.
Many years ago I was shown by Bob Terzoula how to put tape on the blade until we have something like thirty or so thousands of an inch thickness before placing the blade and handle in the press for forming the Kydex.
If your interested in thickness's and want to put the micrometer on some tape, fold one short length of tape over and then measure the thickness with the micrometer. This keeps the "mike" from sticking to the tape. Divide that reading in half and you know the thickness of each layer of the tape used.
Or just use four or five layers of good quality blue masking tape. It comes off easier. Place tape straight up and down the blade, not around.
Using a sharp hobby knife, trim the edges of the tape right next to the edge and spine of the blade. This way the tape doesn't "print" through the kydex and show on the outside.
I have never placed tape on the handle.

Handling sharp things can be hazardous to your band-aid supply!
Especially when removing tape from sharp edges. This is not theory. Work slow and with care removing tape.

[Bill Harsey]

Kydex is a thermal forming plastic used for a lot of things including interiors of commercial and private aircraft.
A heat source is handy for thermal forming kydex. I use two of them, an oven capable of holding 300 to 400 degrees F and a heat gun for doing area forming, like in belt loops or final forming the top of the sheath around a handle.
"Not too thick" cotton gloves help while picking up and working with the warm plastic.
Here is a technique used around here: use scraps of sheath leather as a thermal mask to protect areas you don't want hot when hand forming details with the heat gun. This is very useful.

[PiterM]

Good thread! I'll try to share some of my thoughts about kydex as well, sure

Let's talk about tape on the blade... yeah, that is of course very important step. Masking tape is best, I use TESA brand (popular here in EU, good quality and THICK) and I use 2 layers usually. Sometimes 3 layers (on knives made of more than 0.2" stock). One "trick" that I use is to put final tape coat with thin transparent packing tape. Masking tape is usually not glossy, so when you press hot kydex against the masking tape that creates "micro-texture" on the inner side of the sheath! For most knives it doesn't matter that much but for very fine satin finished blades YES, IT DOES. Glossy & smooth packing tape is very thin (so it doesn't change the thickness of the tape padding in fact) but it leaves the inner side of the sheath mirror-smooth. That is a trick I use on some of the knives.

BTW, these two sheaths I made yesterday and in that case (very very fine satin finish as you can see) I had to use this trick to prevent that finish from scratching.

[Smokin Joe]

I have just a quick safety tip:

Heating Kydex for too long or at too hot of a temp can cause a very toxic gas.
Rule of thumb if it starts smoking don't breath the gas!!!

I usually heat a sheet for 5-6 minutes at 300 degrees, at that heat and duration it usually comes out of the oven as pliable as a sheet of paper. Take this with a grain of salt I do not even rank as an amateur when it comes to making anything out of kydex. But I try and have done some reading on the topic.

[Trip_Wire (RIP)]

PiterM:

Nice work!

[mcarey]

First as many of you know, not all sheaths are functional.

Proper planning for intended use is where I start for our sheaths (And that is not easy to accomplish if you want versatility). We are finding that making a multi funtional sheath is no easy chore.

So give these questons some thought......

What do you want to attach to? (Pack, belt, Molle/ PALS, a combination, etc...)

What orientation? (R/Hand or L/Hand; Vertical / Horizontal / complex angle)

What type of retention do you want? (2' drop, one hand draw, secondary retention)

What hardware is available?

What is your target cost?

I would be interested in what are the basic needs that you guys want for a field / combat knife.