What do you mean by Gravity Casting? You said plaster molds, so you
are just pouring into the mold? Why stop there. Would they have
thought to use some wet and soaked paper or skins to do a steam
cast? This causes a layer of steam as you cap the mold and FORCES
the metal into the mold. Maybe they had an accident where something
caught fire and they put it out with wet rags so they wouldn’t have
the metal explode by pouring water onto it… They noticed that it
was better cast, and eventually they tried it again and again to
You said Centrifugal cast works for you, but why could they not of
poured the mold and then spun it with some type of sling? Now you
have Centrifugal casting. I know it sounds funny, but I think we
sometimes just assume ancestors didn’t know what to do but I think
they were pretty smart. Look at all the bronze age castings of axe
heads, etc… I think you basic smithy that did this magic on a
daily basis would sometimes have a happy accident and remember how
to reproduce it later. Also they would of worked as a team not an
individual craftsman. So while the smith may prep the mold and the
metal, the apprentice got the dubious task of spinning it a sling.
No workmans’ comp back then, so if something happened, you just got
a new apprentice.
Also why not sand casting? You get a nasty chunky result, but after
refinement and fileing,etc you end up with the finished piece. Not
right out of the mold, but with refinement it can be done. It really
depends what you are trying to replicate that they would of made.
The sand casting would be easy if they knew to pack sand around the
item… Cope and drag specifically refers to sand casting by the
way… That is how the early bronze casting would of been done. So
you have to think of you timeline… What is plaster? ground up
limestone/cement. Would they have it available back then? Don’t
know, that’s why I’d look at the sand casting.
If not poured plaster, maybe from Chalk. You have a HUGE coast of
chalk in England used for many things. It would be fun to carve some
of those blocks up and cast. In a similar manner, the Natives of
North America used a rhyolite tuff for casting that they would
carve. But they were shown how by the Spaniards from what I recall,
so I don’t know if they naturally developed it or the spaniards just
helped them refine an existing technique.
And my last thought is that if you want to know how they did it in
the medieval times look to some undeveloped countries that exist
today… Many of those processes were documented and still in use to
some extent today. While “WE” in a modern society have moved on, the
old tried and true methods are still in use and handed down from
generation to generation.
Just some thoughts for ya. Fun topic.