Kydex Foam Press

[Jonathans]

I will be working with Kydex for the first time soon, and gave watched numerous tutorials and WIPs that will help me through a correct process.
I ordered a couple pieces of foam from a knifemakers supply. Now I want to put a press together.
I know its a pretty simple deal, but I have heard talk about correct pressure etc. and want to get it right the first time.
When clamped down, are the top and bottom boards/plates closer together than the combined thickness of the uncompressed foam, or should I be compressing to the thickness of my knife and sheath, and then some more? Is there such a thing as over compressing?

 

[DAVE_M]

*This would be better in the sheaths and such forum*

I will be working with Kydex for the first time soon, and gave watched numerous tutorials and WIPs that will help me through a correct process.
I ordered a couple pieces of foam from a knifemakers supply. Now I want to put a press together.
I know its a pretty simple deal, but I have heard talk about correct pressure etc. and want to get it right the first time.
When clamped down, are the top and bottom boards/plates closer together than the combined thickness of the uncompressed foam, or should I be compressing to the thickness of my knife and sheath, and then some more? Is there such a thing as over compressing?

Trial and error, my friend.

Heating your kydex will be more important than the pressure applied. If you don't heat the sheet correctly, no amount of pressure will yield the results you are looking for. Be warned! You can, and most likely will, overheat your sheet.

My press is made from 12"x12" sheets of 3/4" plywood and 3 C-Clamps. (Middle Right)

Even with 0.080" material, definition can be achieved with the right temperature.

 

[elementfe]

First, do it quickly. You don't have a lot of time to get it pressed when it's really soft and will conform to the shape perfectly.
I pretty much make sure that my top and bottom foam pieces touch each other all around, for starters, maybe a bit more- if it's hot, it all goes where it's sposed to.
It's really a fun way to do a sheath, not much to it.
Oh, and I drill the first couple holes and set the first two eyelets at the bottom of the sheath while the whole business is stuck together, knife and all (mine wouldn't be sharpened yet, be careful!) using a clamp if needed. Then, get the knife out so it doesn't get stuck in there, and drill the rest.
Edit: couple more things- set your kitchen oven for 300F, five minutes will soften the Kydex once the oven is ready, and have your press right there beside the oven so you can slam it all together. I lay the two pieces on an upside down cookie sheet- the reason I don't use a toaster oven is that there's too much direct exposure to the heating coils- indirect heat is sooooo much better than a heat gun or toaster, though some folks get great results with both.

It's helpful to clean up the drill scraff around the holes with a larger drill or countersink bit so the two sides fit together tightly.

 

[Kievanr]

I have had very good luck using an old toaster oven and a IR thermometer.

Here is a spec sheet, as it has temperature ranges for forming Kydex.

http://sekisui-spi.com/assets/image..._Sheaths_Using_KYDEX®_Thermoplastic_Sheet.pdf

I generally aimed for 350°F to 360°F evenly across the Kydex.
I would start with the Kydex in the oven at the lowest temperature that it would go and slowly raise the temp to evenly heat the Kydex.
While the Kydex is heating I would use a heating gun to warm the foam in the press and also warm the knife to be pressed.
This will give you the max working time with the Kydex and also avoid shocking it, which could lead to poor definition.

Hope that helps.

 

[DAVE_M]

First, do it quickly. You don't have a lot of time to get it pressed when it's really soft and will conform to the shape perfectly.
I pretty much make sure that my top and bottom foam pieces touch each other all around, for starters, maybe a bit more- if it's hot, it all goes where it's sposed to.
It's really a fun way to do a sheath, not much to it.
Oh, and I drill the first couple holes and set the first two eyelets at the bottom of the sheath while the whole business is stuck together, knife and all (mine wouldn't be sharpened yet, be careful!) using a clamp if needed. Then, get the knife out so it doesn't get stuck in there, and drill the rest.
Edit: couple more things- set your kitchen oven for 300F, five minutes will soften the Kydex once the oven is ready, and have your press right there beside the oven so you can slam it all together. I lay the two pieces on an upside down cookie sheet- the reason I don't use a toaster oven is that there's too much direct exposure to the heating coils- indirect heat is sooooo much better than a heat gun or toaster, though some folks get great results with both.

It's helpful to clean up the drill scraff around the holes with a larger drill or countersink bit so the two sides fit together tightly.

Using your kitchen's oven is not wise. Kydex, when heated, releases toxic fumes and smells bad. You don't want that in your house.

 

[elementfe]

Using your kitchen's oven is not wise. Kydex, when heated, releases toxic fumes and smells bad. You don't want that in your house.

Good point, and there are workarounds that would allow a toaster oven to produce even heat. As is, though, heat guns and toaster ovens are much more difficult and time consuming to use- if you're doing one, it's probably not an issue, but I never seem to do less than ten at a time. An oven outdoors would be the ticket.
The other half is, you don't want to breathe that stuff in your shop either. It's easy to become complacent about toxic stuff "out there."

 

[Jonathans]

Thanks for the tips guys. Very helpful. I picked up a half sheet oven at auction a while back to keep in the shop and to stay married longer.

 

[Drew Riley]

For heating the kydex, I've tried toasters, griddle plates (which actually worked pretty well), and one or two other methods, but I think anymore, I prefer just using a heat gun.

I just lay the kydex on a metal pan, run the gun back and forth, and flip the sheet once or twice, and it's ready to press.

I use C-clamps too, though I'd really like to get something a lot more efficient. I see where a few makers have used quick release vises with some success.

 

[DAVE_M]

If anyone wants to get serious with kydex. Invest in a IR laser thermometer.

If you really want to get serious, buy a t-shirt press.

 

[Salolan]

I haven't messed with kydex very much, but when I have I used a griddle to heat it.
Here is the basic press I made for myself. The latch is a quick way to lock it down. If I need additional pressure I can use C-clamps on the sides.

Chris

 

[Mitchell Knives]

I use a griddle or a t-shirt press to heat my kydex and a shop press to compress the foam. (In the past I used woodworking style vices, but they kept breaking.)

A heat gun is useful to make minor tweaks after the sheath cools.

 

[PEU]

Tried at least a couple of different style presses, all suffer the same problem, it takes time to clamp them. Best solution I found so far is to lay the rubber on the floor, put the knive+kydex, another rubber sheet and stand on top! Far better results than any of my previous builds. For heating I use a heat gun.

Pablo

 

[Storm Crow]

At some point in the near future I'm planning on building a variation on these scissor presses, which will in part be used with standardized sheath tooling in a low-level production basis.

[video=youtube;z03AgHnWB7g]https://www.youtube.com/watch?v=z03AgHnWB7g&index=3&list=PL2cZtXDTod8kI-6LHJarHYvamGjxJea6v[/video]

[video=youtube;ULYyJbRjb6c]https://www.youtube.com/watch?v=ULYyJbRjb6c&list=PL2cZtXDTod8kI-6LHJarHYvamGjxJea6v&index=6[/video]

My biggest issue is trouble getting the Kydex hot enough without getting too hot. On bigger sheaths I am using a griddle, and on smaller a toaster oven. It's easy to overheat in spots with the griddle if you aren't careful, and the toaster oven will literally go from being the right heat to either too cold to mold or hot enough it's melting from one time to the next, without touching the heat setting. I've taken to testing the temperature with a scrap piece of Kydex before putting in a good piece.

So I'm about to lay down some money on a better heat source. I was looking at T-shirt presses, then at half-sheet convection ovens. Anyone have any thoughts comparing the two?

 

[J W Bensinger]

I use one of the squeeze-tightened woodworkers bar clamps (near the hilt, to keep everything lined up) and one or two vise-grip welding clamps to get the tension. It works very well and it's fast which helps a lot.

 

[Eric@DLT]

I started with this press http://www.knifekits.com/vcom/product_info.php?cPath=41_524&products_id=636 Although when I bought it I don't think it was nearly that expensive. I like that it was metal and was easy to set up and close before the material started to cool. I press it firm and haven't found any problems with over pressing. The foam does wear out faster than I think it should though.

There are some good pictures of people making their own press, good job for them. That is also an option for you. I think you'll have a little more work on your hands getting your designs down to make sure you get the right balance of retention.

I guess the work and money put into your setup is also dependent on how many sheaths or holsters you want to make. I found after the first handful I made for myself, I thought the arbor rivet press was a good investment. Hand punching those things to me was a PITA.

Have fun and make sure to post some pics.

 

[Jonathans]

I will post some pics one I get a round tuit. Thanks for the suggestions.

 

[Phydeaux]

I use a 2 ton arbor press. Once I apply pressure, I jam a soft piece of wire in the rack (gear) to keep it from moving so it maintains the pressure until the kydex cools.

Toaster oven for heating the kydex (garage sale special).

Ric

 

[Bailey Boat]

Has anyone tried leather lining the Kydex??? I love the kydex sheaths but don't want it scratching the object inside (knife or gun)...

Also, being an avid shotgun shooter and reloader I have bags of shot available. I wonder if they could be used over the foam to do the pressing?? Seems like if someone could just stand on the foam that the weight from the shot bags would serve the same purpose...??

 

[HSC ///]

I tried Kydex for the first time yesterday afternoon. I followed Murray Carter's kydex making over 2 parts. I distilled the process into about 9 or 10 steps.
I used a large vise at work and just squeezed it as hard as I could compressing the foam without being ridiculous about the compression. As in I I didn't use a pipe extension for more torque.
My foam is 6x6 sq and 1/2" thick but I doubled up to end up with 1" thick on each side

I found per the instructions of the Kydex that it's very forgiving. One time I didn't position the plates into the vise properly and I didn't get the compression I needed at the opening.
I just put it back into the toaster over, It becomes pliable again and returns to it's original flat shape. I was able to redo the same one over again correctly.

Then I banged out 4 more pretty quickly. They aren't perfect but they were a start,
The first 2 top rivets I have are too high up, but I had done this step all together first so they all turned out incorrect, but functionally they all still work.