I do casting of Railway bits and bobs and I hand mould stuff when I can so the first pic is excellent and shows the mould being made around a pattern, the pattern will probably made of wax or something silmilar . Once the mud/sand/clay mould is made they will cook/heat the mould to melt the wax and harden the mould off, a clay with good refractory properties usually being used if available. as the wax melts it can be poured back into the the wax pattern mould thus making efficient re use of the wax. The now empty hard mould would probably be packeded in sand on the casting floor and a lid added to the mould with a runner and riser to allow metal in and gas/air out. The pattern in this case cannot be removed as in modern split box casting as it is double undercut.
If the wax were to be left in the mould it would be hugely wasteful on the scale shown being vapourised as the metal went in, so the above method seems most probable. I have seen this type of casting in China in some really out lying poor regions and its great to watch.
In making smaller item they would probably use lost wax proper for things like brass knobs, lock components etc but the moulding process would be the same in essence but they would not bother recovering the tiny bit of wax.
Tin Smith can in some cases simply mean a metal worker, even small iron smithies used to work other metal including casting lead and bits of brass, the material probably just refers to their primary metals worked.
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