You can get to around 200C with oil-based media. But oil goes bad pretty quickly, and it leaches tons of crap out of everything. Above that temperature, you n

You can get to around 200C with oil-based media. But oil goes bad pretty quickly, and it leaches tons of crap out of everything. Above that temperature, you need molten salts or liquid metals that are extremely corrosive. Your other option is to use gaseous media instead.