I am looking to find out if its possible to create a 70mm x 50mm and 10mm thick metal case with a switch that when turned on can create alot of heat without the use of a power supply?
Take the guts out of the switch and glue the handle to a kitchen match. When you move the fake switch handle, the match lights and starts the contents burning. The contents are your option.
So now you added an image of a hot plate? What exactly are you trying to do and try real hard to explain it. When you say no power supply that implies no electricity. So what does the switch switch? I give up.
When I say power supply I mean without mains power. So it would be battery powered. When turned on it would heat a filament inside and make the outside hot.
Just have the switch short circuit a battery. That makes plenty of heat (if you've ever put a 9 volt battery in your pocket with some coins). If the box doesn't fit the battery you want, make the box a different size.
The metal box only has to be hot for a short period of time - about 10 seconds, how long would it take until the short circuited battery explodes or becomes dangerous?
Look into low voltage cartridge heaters. Google Cartridge Heaters and find some low voltage ones. You aren't looking for much heat. The problem will be batteries that can deliver enough current over a long period. How long do you want this thing warm?
I would start with getting familiar with heating elements, especially cartridge heaters like this. Then get familiar with batteries that will fit into the application. Then worry about a means to control the temperature.
I would start with getting familiar with heating elements, especially cartridge heaters like this. Then get familiar with batteries that will fit into the application. Then worry about a means to control the temperature.