coil cover

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 have 3 questions 1) Brand new to detecting. Have read up on machines that are affordable that focus on non-ferrous. I chose a Gold Bug Pro. It comes with a small 5 in. coil which dosen’t cover much ground. Rather than only consider the Fischer 10 inch coil I am wondering why they don’t offer...