I wasn't there for long, but that's for reason! I made a small vacation for myself, also - 3d printer arrived. So I've been working onto fixing some printing issues, caused by troublesome Z-axis mechanics. Now everything seems to be fixed, I regained access to 3d printing stuff, hooray! :)

Of course, I tested modular electromagnets
It seems, that I failed to produce reasonable design of winding, ahaha

So it's must-have thing to wind half of them in opposite direction! Otherwise, you would need to connect opposite sides of coils, leaving loooong wiring between, that isn't pretty at all! Now I am into designing cheap winding machine for that purpose, motorized this time

I've made only one half of magnet, because second half operates similarly:

And I want to say, that it performs very well! Self-proclaimed "modular" electromagnets are pretty small and light, use a little amount of cooper wire and also pretty strong compared to beefy convenient electromagnets, even with nails used as a core material. So I can say, that with nice core material or control circuit, which can sustain powerful magnetic field, it's a win : )

Now about core material, I thought a lot about using induction heater and I already have one, of course, but this method requires deep vacuum pump, I think I can do it without low pressures.

Using H2 intake as a heating element with O2 originally in chamber - it's the most simple solution, which I found, only requires some high-temperature clay, insulator (rubber?) and electrolytic cell.
Plus remote control for the reason of safety, of course.

It's possible to pump high amounts of energy into coil with control circuit, thanks to great efficiency. And probably... It's possible to use that instead of hardcore core materials, needs to be seen! To test that, I need to establish adequate bootstrap driver, because IR2117 has zero passion to work! >:{
(probably it self-destroyed at some point, I need to built similar thing on NPN-PNP transistors now)

With nice core materials it would work best anyway, so it's good to have ability to produce such things!