How do you convert an appliance from natural gas to propane?...
Fit it with toy airplanes!
Smaller jets. LPG bottle is way higher pressure than municipal gas. My understanding, totally untested, is that propane appliances simply have a smaller orifice and all you have to do is swap them out and you're ready to rock. I kind of like the idea of using a regulator tho. If you don't have regulators lying around you can get a needle valve online for cheap. Of course, if the manufacturer is helpful they'll be the way to go. I have done none of this so don't PM me any singed eyebrow pics.
I accidentally a generator synchronizer for like $5 quite awhile ago. I thought it was a load cell receiver.

Is there any conceivable use for such an animal other than sync-ing generators?
Sorry, BS. It's the quick & the dead 'round here.