Those aren’t the things I’d personally want to make, but I’m filing this away in the “might come in handy” bucket.
A while ago I was looking to buy a furnace to cast pewter in laser cut molds. There is a lot of videos on the subject.
I built a small furnace during lockdown for that same purpose. Internal 220 deep x 155 high x 190 wide. The Controller, Solid State Relay and heat sink I bought off ebay for literally <£5. The control box is laser cut from here and it can be seen sitting on the shelf above the furnace.
Very nice setup. I was looking at something as inexpensive and simple as this to start with since pewter has a very low melting temperature.