Once way is to buy the copper circles from Metaliferous in NY another is to get a disc cutter and make your own.
Not sure where I got this one but I like it because of the clear acrylic top
In this pic cutting 18g copper circles
You would be impressed if I had cut all these but I did not
I got the circles from metaliferous - after I was cutting I remembered I had some in my enamelling supplies so off I went and grabbed them.
One of the tools I bought a long time ago was a hole punch - it has various sizes and does a great job and is easy to use
I put one side of the handle (the bottom) into the vise.
It comes with an adjustable piece that lets you set it so you can repeat the hole. If you work out the center on one of your pieces you can set very easily and makes punching the hole consistent
so you can make a ton of center punched pieces for stamping.
I will be attempting to etch so I made up a bunch so that I can either put the pnp blue - but they are so small - but I think I want to try a resist by using a rubber stamp - my zentangle texture mats as another way to transfer the designs
that is to follow