I made a silly beginner's mistake: I purchased some surplus rotary solenoids from electronic goldmine without paying close attention to their power requirements ("Oh, they are so cheap!"), so I assumed they were 12v and reasonably powerful. There are no specs - just the catalog blurb (below).
Neither assumption is true, as it turns out. My benchtop power supply only goes to 30 volts and at that power, the solenoids have almost no force.
Before I try to find a 40 volt power supply, I'd like to know: will force increase by any significant amount with the increased voltage?
Of course a 40 volt power supply will probably cost more than just sourcing 12 volt solenoids but I thought I would ask.