My home made press really is nothing more than 2 pieces of foam that i ordered from Texas Knife, my workbench, a 1 foot square piece of 3/4 inch plywood with some 2x4's glued and screwed to it, and then wood working clamps.

As you can see from the picture, i put one piece of foam down on the corner of my workbench, then the piece i am compressing (knife and KYDEX® sheet in this example, and then the next piece of foam, and finally the 3/4 inch plywood. I then compress the heck out of it with the clamps you see holding it down. The hole process takes less than 30 seconds.

If I'm making a project like the 1911 Magazine holster and I want a flat side on one side, I simply put the side that I want flat directly on the work bench, and put the two layers of foam on top, and so on as above.

Many people use foam that they have scrounged up from camping pads or other sources. I think that the foam that is sold specifically for the purpose forms much better to odd shaped items like a gun magazine. If you are just working with fixed blade knives you may be able to get away with sleeping pads, though when it comes to the handle, you might not get the shaping you were hoping for.

They sell commercial presses that use the same foam for $79.99. That seems like a waste to me if you have some decent clamps. Then again if you don't have the clamps, they will run you that much for 4 anyway, so maybe the press is the right way to go for you. Good luck making your home made press for KYDEX® sheet!