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

Get yourself a rheostat to control the current going to your heating element. They come in all shapes and sizes with various capacities, but these ones for controlling fans and routers seem to work pretty well for most of our steam engines and are relatively cheap, like these that are sold from a hundred sources on ebay:

https://www.ebay.com/itm/165989343345


Look around and you'll find plenty more at different price points, but don't forget to figure in shipping costs.