John, it's been awhile since I flew with IC glow engines -- all electric now. But as I remember it glow plugs were just a coil of very fine platinum wire the glowed when you put 1.5V through them, and once the engine started would continue to fire the engine without current.
I don't actually know if it's caused by catalytic combustion, or just the tendency of a fine wire to keep glowing when heated. But I imagine most other metals would have oxidized quickly. Don't know if they needed pressure to work. Sorry. Anyway, they worked, and are still available to try.