coil control device

Do you know how to make coils? Making your own coils requires knowledge in electronics knowing how many turns to have. I am wondering if a coil base can be made using a 3D printer and wire from a transformer can be used for the wire wounds. I wish I had a 3D printer and also I wish I knew of...

I made a coil control device for the surf that is simple and easy to make. It also has very little drag in the shallow waters of the Atlantic Ocean. You just use a heavy-duty plastic coat hanger and wire tie it to the front of your detector shaft. I also came up with a cheap and easy belt...