Best way to heat a metal ring to 300-600°F in a box for a DIY project

hi everybody. my names jonny and im working on a project. i have no electrical experience so please bare with me. i need to create a unit in a box that will heat a metal ring to between 300 and 600 degrees F. i need the main base unit to allow fior the metal ring to be placed into it ina recess and heat up. it seems simple but i have no clue. thanks so much for your time

You're not trying something out of Lord Of The Rings, are you? :-)Sounds like this would be a good  project for RF heating.  You'd need a radio transmitter, and a small coil adjacent to where the ring is to be.  The transmitter causes an RF field in the coil which is picked  up by the ring, and eddy current heating within the ring will cause it to heat up.When RF is used to heat metal objects it's more usually called Induction Heating and there is a good Wikipedia article on it.  They give an example of heating a 25mm bar using 15 kW of RF, but you'd probably get away with 20-50W for a small ring, which you could get from a surplus transmitter which should not be expensive.I have no idea of the coil size you would need - it would certainly depend on the frequency and maybe on other factors.  Google "RF heating of metals" or  "Induction heating" and you'd certainly get much more information.  I found a DIY project here which might be a good starting point.  Good luck, and have fun!

I don't think you need radio frequencies. A coil run directly from the AC mains supply (110V or 240V) and wound around or under the recess would induce a current in the ring. You will need to look up the transformer rules for voltage and current, treating the ring as a secondary winding with 1 turn. You will want to step down the secondary voltage to a few volts or less, so you're probably looking at 100-200 turns on the primary coil.
WARNINGS: Mains electricity is dangerous. Always work from an outlet with an RCD safety device fitted, and put a fuse in your circuit. Never work on live circuits. Ensure all wiring is properly insulated. The ring will experience magnetic forces and depending on the material may need to be anchored. There is no power regulation in the simple transformer circuit, so depending on material, winding details, etc. the ring may get very hot indeed and become a serious fire hazard.

this is what im trying to do. create a base that i can click in that ring and have it heated. as you can see the ring is really a hollowed out cylinder. i would need to be able to click it into the base, turn it on and then make sure it shuts off when it reaches the proper temp. thanks so very much for your previous response. it makes me so very happy that the internet has places where a wealth of knowledge can be found.  

thanks so  much for your input. i actually understand what you said. check out the picture above to see what im after. thanks again

i was looking into stuff in my house to make a comparison tech wise. i found my electric kettle to be the closest to what im after. so the metal ring would be heated up and then a "bi metal switch" appears to be the thing that would kill the heating element. so it looks like im trying to figure out which metal would heat the fastest and retain its heat and which method to heat the metal through contact. thanks again

I have not used an iron for sterling so I'm not sure whether or not it will work. However, I am a metalsmith that uses a torch and silver solder to join silver and other metals together. I don't think the iron will work, however, if you do not care if the piece gets "messed up" go ahead and try it. Is there a stone in the piece? Too much heat can ruin the stone. If you do not want to risk it, you can try epoxy glue, found at your local hardware store. The epoxy may work if the ring is not an "everyday wear" piece. If you use the epoxy, be sure to sand the two areas being joined and mix the two parts of epoxy equally. I hope this helps.

if you check out the picture above youll see im not going for a ring to wear. its a hollowed out cylinder about 1/2 an inch round. i need it to lock into a base and then heat up pretty high. 600 degrees max.