During my research into ancient casting techniques I came across an interesting technique called “Luted Crucible Bronze Casting”.
‘Luted’ or sealed crucible casting is a low-cost and low-tech method of casting, relatively unknown outside India and West Africa. It involves sealing the raw ingredients for bronze - copper and tin - into one half of a peanut-shaped crucible made from mud. The other half contains the wax model to be cast. The whole thing is baked in a furnace, and when the metal is molten it is flipped over, and the liquid bronze fills the cavity left by the wax.
See the article in full on UCL Institute of Making