What materials would work for a waffle iron? I'm somewhat curious if I could make myself something like this (though without the retro enclosure, at least initally):



While cast iron would probably be the best material, I'm not sure if I can easily obtain a billet of the proper size (likely would machine the iron), so I'm curious what other materials would be best.

Is steel ever used?  I'm imagining it would rust easily, but what if it was properly seasoned?  Can you season aluminum at all, or is it moderately non-stick by itself?  All the aluminum cookware I've seen is (cheap, and) Teflon-coated.

Waffle batter to my knowledge is fairly high in fat relative to others (pancake, crepe) so it "fries" more than "bakes", but it's not exactly loaded with it to the point of no-concern.
Aluminum is easy to CNC mill and it can be make non-stick

It needs to be finished to a semi-gloss, and have a slightly undulating (smooth wave pattern) surface to allow for release

It should be hard-anodized to reduce surface pores and future oxidation. Do not scrub hard-anodized surfaces, just soak

Cast aluminum will most likely have too many surface pores to me useful