Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.

Hey so I've been thinking about this for a while now and have been planning on testing it but don't have any means of measuring results. Just so we're on the same page with my thought process... A coil of wire with current flowing through it creates a temporary magnetic field around the wire. If coiled the adjacent segments' magnetic fields 'cancel out' except in the center where it is amplified. If a ferromagnetic material is placed inside the coil the magnetic field is increased still.
So what if a high gauge of copper wire(let's say 25), is coiled around a lower gauge of iron wire. What you have is a flexible electromagnet (assuming you have a power source) correct? If this flexible solenoid was coiled around another core would there be any significant difference in the amount of force produced and what would the field lines look like?