[ExI] horseshoes, was: RE: i predict chaos

Adrian Tymes atymes at gmail.com
Wed Jan 5 18:06:55 UTC 2022

On Wed, Jan 5, 2022 at 9:23 AM spike jones via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> As I was typing a reply, an idea occurred to me.  Perhaps you have seen
> someone make a sandcast something at home, using molten aluminum.  You make
> the model out of a kind of specialty wax, then you pack around it with a
> fine-grained sand mixed with a specialty silicate infused ceramic epoxy
> stuff, let that harden, then pour molten aluminum onto the model, the wax
> melts and flows away, chip away the mold and there’s your aluminum thing
> the same shape as the wax model.
> OK, well I suppose one could make a horseshoe that way, but another idea
> would be to make your model out of tin/lead 37/63 eutectic, as used in the
> electronics industry for solder.  That way the model would be soft enough
> to work with a hammer without making all that racket that hot steel makes
> when you work it and it would still be rigid enough to do the kinds of fit
> checks and such that the modeling wax isn’t strong enough to withstand.
> Example: tap a threaded hole in the tin/lead model, that might create a
> workable threaded hole in a sand casting.
> When your cast sets up, Turn the casting upside down, put it in an
> ordinary propane webber grill full blast, let the metal melt and flow out
> since it only needs to get to 180C.  rig up a homebrew blast furnace with a
> leaf-blower and charcoal, with the structure made of those interlocking
> garden-wall stones, where you substitute metal pins in place of the plastic
> ones to hold them in place.
> Now you have your horseshoe shaped cavity (or cavity shaped like a car
> part (such as an adapter plate)) in your sand cast, your crucible of molten
> iron, ready to pour.  Hmmm… pretty expensive horseshoe perhaps.  But we
> would have fun rigging up the stuff we would need.

So here's another idea.

Start with my old programmable shape array -
https://patents.google.com/patent/US6487454B1/en - pressing a disposable
surface coated with something that hardens with electricity.  (I hear that
a paste of corn starch + silicone oil hardens up to a consistency similar
to concrete with 12V @ 500 mA.)  Press it into the shape of the mold you
want (as designed in some CAD tool), apply electricity, remove the array
(since it might not stand up to high heat), pour the molten iron, wait for
it to cool, cease applying electricity so the mold becomes soft, and remove
the mold.
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