Making a Kydex sheath is a process which is best learned by DOING! It is a skill, and, fortunately, the curve is pretty steep, so while your first few efforts may be laughable, you'll quickly learn how to make sheaths that are equal to those offered by commercial enterprises! The field of synthetic sheaths is more reasonable for small operators over leatherwork for a variety of reasons. First, the expense is lower. Second, there is no need to treat, color, etc the synthetic products, so there is less chemical handling and processing. Most people also have most, if not all, the tools required for making a synthetic sheath, while leather ones require some sepcialized equipment that can get expensive. This isn't to say that leather isn't cool! Quite the opposite, in fact. What I'm saying is that you can make one or two synthetic sheaths with a lot smaller investment of time, money, and resources, than you can with leather.
Please note that anything you read here is based on my experiences, and a lot of it is my opinion. This webpage is meant as a starting point, and most of the recommendations come from the School of Hard Knocks. You can learn a lot from my mistakes, so pay attention! My way isn't the only way, the "right" way, or anything else, but it is a way for you to economically produce professional looking and functioning sheaths. The Big Guys may not appreciate this page much, but it is my belief that you get more satisfaction from doing things yourself, especially if that means no long wait or ridiculous prices to pay.
Just some things before we get started...this page is meant for information only. If you are injured or there is an accident of some type, then it isn't my fault. Also, if you use this info to do illegal stuff, then that's also your problem, not mine. All the regular precautions of working with tools hold true here. I assume you know what you are doing on a basic level and that not each and every detail need be provided, so good luck and don't contact me if a knife gets ruined or you get injured due to sheer stupidity or inability to apply common sense and responsibility.
Also, for ease of typing and reading, I will be using the terms "Kydex" and "Concealex" as synonyms. When I refer to one I am generally including both in the description, it's just that it gets tiring to read and write "Kydex/Concealex" over and over again! Enjoy the page and good luck!