Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Here's something I've been thinking about for some time.  Consider it an unproven idea but one which hold promise:

If you are good at machining curved aluminum, and don't mind a custom aesthetic to the outside of your boiler, I have seen where someone (Paula?) has made a curved block which wraps around the bottom of an Empire boiler.  The block has a hole drilled in it to snugly mount an electric cartridge heater, and the block serves as the heat transfer mechanism. 

This approach could be scaled up to size of your boiler, using more than one of these cartridge heaters made for household water heaters: https://www.amazon.com/DERNORD-Immersion-Cartridge-Heating-Replacement/dp/B074K98XR7?th=1

Please note these heaters come in 120 and 240 volts as needed and are 500 watts each.

Just an idea.  Maybe you can find some inspiration in it.

Best of luck!