Ok here's the dilemma. Had a coil disintegrate on me in a grande. Went to the hardware store and got a total look of confusion when I said I need a 'stainless steel' spring or coil . they couldn't tell me if the springs were stainless or not . I need help with making a replacement .
I should also add that it is also quite likely that Lava just uses a quality steel coil. It is unlikely to rust as it is almost always immersed in wax which would not cause it to rust.
However, when making a replacement, you couldn't go wrong with stainless steel. Any material that is NOT magnetic is either a high quality stainless or aluminum and aluminum would be very light and much softer. I don't think you'd want to use aluminum wire to make a coil though.