I have been using copper tubing for a couple of years now, so I have learned a bit about it and want to pass on that knowledge to you.
Copper tubing comes in different sizes. You can go as low as 1/4" (maybe lower) in diameter to about 1 1/2" in diameter at most local plumbing stores. I am sure you can get it a bigger, but I am talking about local sales unless you live near a place that specializes in copper.
Tubes are measured by OD (outside diameter) or ID (inside diameter). You can have a variety of sizes for different jewelry design. One of the biggest things that I have learned, however is that copper comes in a variety of thicknesses (K, L or M generally), The thicker the tube is the heavier it will be, so planning on which kind to use for jewelry making is a good idea.
What else do you need to know? Some copper can be coiled (soft) and other tubes cannot (hard). This piece is a hard temper tube which is not bendable without LOTS of annealing. Soft tubing bends easily and cleaning it is a little tricky.
Let me apologize for some of these pictures. I took them while I was hustling to get ready for last weekend's show, so there is a mess in the background.
So, once you have the copper that you want, you need to cut it. There are different sizes of tube cutters. These can also be purchased at your local hardware stores. Although some will cut multiple sizes, if they are too small cutting larger tube can do a number on your hand. I suggest having a few different sizes on hand. Here are my main go to cutters.
To speed up the tube cleaning process, I like to use a dremel. You can use different attachments depending on what you like or, in my case, depending on what I have on hand. Make sure when you are doing this you hold the tube VERY TIGHT. Also, wear glasses or goggles AND you might want to wear a dust mask as well.
After using the dremel, you can do some final cleaning with a burr cleaner. This part is a pain in the neck, but important. I clean them until they are smooth to the touch. That little gray burr tool can be purchased for under $10. You will need to change the blade occasionally.
The cutting can get a little tricky when cutting narrow pieces. It is important to put the tube in just snug and turn the tube in the cutter rather than trying to turn the cutter around the tube. The reason being is that you need to get enough of a cut so that the tube doesn't go lopsided. Once you have a beginning cut, you can tighten up the cutter and rotate the cutter around the tube.
Once cut, the other side needs to be cleaned. If you use copper that is soft, this is almost impossible because the tube will bend. This is why I use a hard temper tube and you do not anneal before this time as it will soften the tube.
Once it is completely cleaned you can then anneal. This will soften up the copper. You might need to anneal a few times between hammering.
Now, it's time to hammer. I happened to find this chasing hammer in an antique store with a very large head. Looking for tools in antique stores is one of my favorite things to do. It's heavy, but I don't have to swing it as many times and it covers the entire tube. These are my two hammers. One is modern, They are both a little beat up, but they work fine for this kind of hammering.
And there you have it.... I typically tumble them to clean them up and use liver of sulfur to darken them. They are then ready to make some basic hoops from or you could get a little more creative and include beads, discs or anything else your heart desires!