There is a massive amount of honey in the cappings. A hot box is traditionally used to extract this honey from the capping wax. This is then sold as oven honey. Oven honey has special properties and not heated too much so that the flaviods and pollen, all the goodness of honey, separate from the honey and float to the top, mixing with the wax.
A hot box is a rectangular open metal box, about 500mm deep, with an element underneath. They would fill this box directly from the cappings being cut from the frame. It has 2 taps on it. What would happen is the honey separates from the wax. Because honey is a lot heavier than wax it goes to the bottom. The honey is run off until the white wax starts to come out, then you run off your wax. The commerical guys will sell what is called oven honey.
Top heat is better than an element at the bottom. You don't want to cook your honey.
The normal solution to melting wax for the hobbyist is to buy an old deep frier. Get an engineer to drill a hole and put a tap in it. Then it's really easy to to run the wax out. Fill the bowl with a little water. When the wax melts it separates into 3 layers; water then honey, then wax. Turn the tap until the water stops and honey pours out then the wax.
The solar melter doesn't use power and works even on semi-sunny days.
One suggestion is to put all your wax into ice cream containers and stick it in the microwave with a cup of water (to prevent stress on the magnetron). Put it on for between 8 and 10 minutes, take it out and place it on a cooling slab and in an hours time you have honey with a nice film of beautiful wax on top. It is said that as long as the honey does not go over 73°C it does no damage and it is still healthy. The honey derived this way is fine. The magic 65°C /73°C is over heating the heating and “all” supermarket honey is over heated deliberately so as not to crystallise and last longer on the shelve.
This hot/oven honey is lovely. The water has been driven off so it is thicker, like axle grease and it does not tend to go hard.