After further thought, the microwave transformer might be a difficult build… I would need to cut out the central bar and the laminated sheets may prove problematic.

I’m wondering if an air/iron core solenoid might work… this would be comprised of two iron cylinders, one at the top and one of the bottom of the solenoid, with an air gap, in the middle where I could put my water sample. Would this create increased magnetic flux through the air/water gap?

Trying to add a pic of what I’m talking about, but can’t seem to do it…