I have a few knives that have nylon sheaths.  I am real­ly not hap­py with the nylon sheath.  Besides keep­ing costs down, they breathe and allow the water to evap­o­rate off the knife to pre­vent it from cor­rod­ing.  How­ev­er, I am not real­ly hap­py with a cou­ple of them, and have been inves­ti­gat­ing sheaths online, and am hav­ing a hard time find­ing one that will fit my knives, so I am inves­ti­gat­ing kydex and mak­ing the sheath myself.  

Here are some of the resources I have found that might help me, and maybe you:

How to Make a Kydex Sheath Part 1

How to Make a Kydex Sheath Part 2

Well, this is on the list of stuff to learn to do, even though it looks sim­ple enough.  Just Google “Kydex Sheath” and see a ton of results that come up.