Flux
Flux is a powder which is required for Welding and also used as a catalyst in a Blast Furnace. Flux can be obtained by grinding specific items in a Quern.
Flux can be obtained in a number of ways, one of which is from its native ore, Borax.
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Some rocks - Limestone, Dolomite, Chalk, or Marble - can also be used as flux, after being ground in a Quern. Other items, including Scutes, Clams, Mollusks, and the edible remains of Shellfish can also be used to create flux.