OT: lost was casting equipment, DIY

Since the topic of lost wax has surfaced, I have a question for anyone
involved in the process, especially anyone that has built their own.
I am interesting in making a centrigual spin caster. Used these years
ago when I used to make jewelry. I watch for them on eBay, but they
seldom show up. I've thought about making one using an electric motor
with flywheel, and a clutch between this and the spin casting unit.
Would not be hard to scrounge all the needed parts, but have never seen
it done this way. Obviously a large spring is much cheaper and easier to
mfg, but for a dumpster diver like myself, the motor/clutch would be
easy to put together for next to nothing.
The one thing I'm not really sure about is just how fast the spring
models spin on average. Anyone have any idea?

Jon