I'm constructing an typical electromagnet, wrapping coil x amount of times around a 1" diameter iron bar, and getting power from 'D' cell batteries. My question is how thick can the wire's insulation & jacket be? Most of the examples I've seen used a nail, with 22-26 gauge copper or magnet wire that has a thin coat of enamel insulation. I'm proposing to use a 5mm (4 gauge I suppose) copper core wire, with nylon insulation and a PVC jacket. The total thickness of the wire is about the size of a pen. Would this type of wire generate a magnetic field? Thanks.