Hello Ed,
Welcome to the world of hobby rocketry.
I must say that I'm a bit worried about a thing or two. First, you mentioned right off the start that you've "built a few small rockets." That's great! So have any number of Cub Scouts and even some Tiger Cubs. But I must say that this has barely helped start you on the road to high power rocketry and has done absolutely nothing to prepare you for building your own rocket motors of any size from scratch.
Second, you mention that you're going to start your first High Power Rocket Build. Again, this is great, but are you and your design actually ready for the world of High Power Rocketry? There's a long road that you have in front of you, but you seem ready to skip a few (or more than just a few) miles worth of experience and get right into building your own motors from scratch. You haven't even built your first high power rocket, let alone flown it for a successful L-1 certification flight. Think of this process as building and climbing a tall ladder. Skipping rungs will just end up getting you in trouble one way or another.
If you are building your L-1 cert flight rocket from scratch that's also great. I did that very thing myself, lo these many years ago, But I must ask who is helping you to make the transition from low-power rocket design and construction techniques to high power rocket design and construction techniques? There is a huge difference between the two. I had help and I needed it. My initial designs were great, but completely unsuited for high power rocketry.
You asked about the rules for building your own motors from scratch. I would suggest that you first check out the rules for high power rocketry certification. Why? Because you may not certify at any level with a scratch built rocket motor. You must use a commercially manufactured and certified motor for any and all high power certification flights. So no, building your L-1 cert flight rocket will not include building your motor from scratch. There are motors on the market that will require you to assemble the motor but that's a world of difference away from building your own motor from scratch.
As far as providing you with a reference for the rules, licenses, and certifications you might need? I would suggest going to the
www.tripoli.org web site and scroll down and read everything about certifying Level one. All the information that you need is there if you keep reading. Its ok if you want to read about research motors, but you're not high enough on the experience ladder for that yet.
Next, you mention that you will be "testing different types of APCP and R-Candy Motors." Let's start with the testing of the different types of APCP motors. Right now the only APCP motors that you or I can buy are all commercially manufactured low power motors. They're great. I prefer testing them in rocket flights myself. These motors have already been certified, their propellants classified, and their properties verified. If you want to build a test stand with a load cell and all the other recording necessities, that's a fine goal to work towards, but again, you're not there yet.
If you are planning on testing your own APCP "research motors" then that's also a fine goal to aim for down the road. But you're not there yet. If you've read the responses on this thread you will note that building your own motors is costly, can be dangerous, and will most certainly not save you any money until you are building them in at least L motor size if not larger. And even then it will take time to pay for the initially greater costs of all the equipment and chemicals.
As far as I know, there are no commercially available "R-Candy" motors or any other "sugar" motors for that matter on the market. There are none that are certified for rocketry use. So please do not start buying them from anybody in order to start testing them. That would be very illegal. And in the same way, please do not start making your own sugar motors following anybody's YouTube videos expecting to show up at a NAR or TRA club launch someplace and expect to be able to fly them. It won't happen.
You have a long climb ahead of you in this hobby. Its a good climb. Its a fun climb. Its a climb that you will find all sorts of people ready and willing to help you move further and higher. But there's no substitute for experience when it comes to building, designing, and climbing the ladder. Please don't skip any rungs on your way up. There's no substitute for experience.
And lastly, remember this, there's no such thing as a free launch!
Brad, the "Rocket Rev.," Wilson