scrap yards are great for 2' copper. It is used for sprinklers in buildings and many have offcuts left over which are the size we are looking for. i got 1.7m 2' copper for 4euro ,$3,

2 inch copper was really hard for me to find too. You can check your home improvement stores but their biggest diameter is probably 1 inch. Look up plumbing distributor and ask if they will sell you a length of what you are looking for. Chances are they will not want to, or charge you an obscene amount. I happened to locate a hardware store ,hardware store, not some huge home improvement shit-hole, that carried 2 inch diameter. 5 Dollars a foot, not cheap, but I took what I could get. Even if it was pricey, I like to give some business to the good old stores. Scrap yards? I should have thought of that, but come to think of it I have no idea where one is. I will definitely look hard for one next time if I could find a deal of 1.7m for 5 dollars!
As for cleaning out copper tubing, I have had success with a few methods. First and foremost, clean all tubing to perfection BEFORE building the still. If the flexible tubing is new you're fine, but if not, assume it's dirty ,if you're a perfectionist like me,. Bend it out straight with a vise - this takes time. Anneal it well in the areas you will have to bend because it's probably work hardened by now. After this cools you should have a layer of black crud on the outside but I don't think this gets on the inside. Here's my innovation - take a wooden dowel rod that is at least half the length of your tubing - if the tubing is too long you will have uncleaned space in the middle - hard to say what to do about that. Cut a thin slit in the end of the dowel, that goes about 2 cm in. Take steel wool and slip it into this, so you can firmly wrap it around the end of the dowel, allowing it to spin without the steel wool coming off. Hook the other end of your dowel into the chuck of your drill. Now you have a motorized copper scrubbing machine! Slide it inside the tubing and push it down and back imany times until you can tell it is shiny inside - use the tubing like a telescope and look at a light bulb. When you are done, use A LOT of water to rinse out any broken off steel wires that will rust. Allow a salt and vinegar solution to sit in the tubing for 10-60 minutes, and RINSE OUT TRHOROUGHLY. Now you can bend your tubing to how you want and it's clean inside. Finally clean off the outside to make it look neat.
In this order:
1. Bend straight
2. Anneal
3. Scrub inside
4. Rinse inside
5. Shape
6. Clean outside