reltbracco on Nostr: So the reason the heat matters for waterproofing isn’t because of the glaze. In ...

So the reason the heat matters for waterproofing isn’t because of the glaze. In fact, raku glazes exist (and can be very beautiful — iridescent and metallic)!

In raku firing, the clay itself doesn’t get hot enough to “vitrify” — in which silica in the clay itself turns to glass — so it remains porous. Unglazed pottery that is fully vitrified should still be waterproof (though because it’s likely to be rough in texture, it’s harder to clean). By contrast, glazed pottery that hasn’t fully vitrified will absorb and release water (and likely also chemicals from the glaze).