Strangelv: Strangelv moved page Sand casting to Sand Casting: Capitalization

2023-05-13T17:25:00Z

Strangelv moved page Sand casting to Sand Casting: Capitalization

Dietzler at 14:54, 2 May 2012

2012-05-02T14:54:58Z

Farred: adding category

2012-05-02T04:55:45Z

adding category

Dietzler: Created page with "Casting Metal on the Moon By David Dietzler and posted by author. Engineering details might seem dull or trivial, but they can make or break us. There won't be any ISRU and boots..."

2012-05-02T00:28:47Z

Created page with "Casting Metal on the Moon By David Dietzler and posted by author. Engineering details might seem dull or trivial, but they can make or break us. There won't be any ISRU and boots..."

New page

Casting Metal on the Moon
By David Dietzler and posted by author.
Engineering details might seem dull or trivial, but
they can make or break us. There won't be any ISRU and
bootstrapping on the Moon without metal casting. Three
dimensional printers that use lasers or electron beams
(which require vacuum, free on Luna) to fuse powdered
metals, glass and/or ceramic into small parts that can fit
in the hand and medium size parts with dimensions of
one or two feet will be used to produce all sorts of parts
on the Moon. Barring the creation of giant 3D printers we
will need to cast large metal parts on the Moon like
vehicle chassis frame members, axles, wheels, struts, etc.
When we can we will use rolling mills and/or extruders to
make things, but we might want to cast up the rolling
mills and extruders with lunar materials rather than ship
these massive devices to the Moon!
Aluminum and magnesium are often sand-cast
but they might also be cast in plaster molds with plaster
obtained by sulfuric acid leaching of highland regolith.
Plaster, CaSO4, is also a cement setting time retardant
and Portland cement contains up to 5% of this compound
by weight. Iron, steel and iron alloy (e.g. iron-aluminides,
iron-silicon, iron-manganese, iron-nickel) casting is
going to require sand molds. Foundry sand, also called
green sand, is made of either silica or olivine sand, two
substances we have on the Moon, water that can be
obtained in various ways and rigorously recycled,
bentonite clay and sometimes pulverized coal (forget coal
on the Moon). We will have to do casting in pressurized
chambers with dehumidifiers to recover water vapor from
the drying sand mold and powerful cooling systems
because it will get very hot inside when working with
molten metals and interior pressure will increase as
temperature increases. Casting chambers will be built of
metal and concrete, not Kevlar!
Here's the detail I am hung up on; there is no
clay on the Moon because there was never any water for
the hydrological processes that produce clay to occur.
Clay is essential to bind the sand mold. We might be able
to synthesize clay on the Moon. At:
w w w.patentstorm.us/patents/6565643/description.htm l
we read that, "U.S. Pat. No. 3,803,026 describes a
process for preparing a clay-type material in which an
amorphous gel comprising silicon oxide, aluminum
oxide, and, e.g., magnesium oxide is subjected to a
high-temperature ageing step in an autoclave.
C.R. Acad. Sc. Paris 7 292 describes a process for
preparing, int. al., clays comprising aluminum, silicon,
and, e.g., magnesium by way of a co-precipitation
process." Silicon, aluminum, magnesium and their oxides
exist on the Moon. I suspect that it will be more practical
to synthesize clay on the Moon than upport it from Earth!
It is also possible to bind foundry sand with resin. At
http://en.wikipedia.org/wiki/Shell_molding we read:
""Shell molding, also known as shell-mold
casting, is an expendable mold casting process that uses
a resin covered sand to form the mold. As compared to
sand casting, this process has better dimensional
accuracy, a higher productivity rate, and lower labor
requirements. It is used for small to medium parts that
require high precision. Examples of shell-molded items
include gear housings, cylinder heads and connecting
rods. It is also used to make high-precision molding cores"
The Wiki article states that this is used for small
to medium sized parts so we might still need clay for
large part casting. Resin could be made in lunar labs and
we would need some way to recycle it possibly by
leaching unused resin out of spent molds with an organic
solvent and by extracting vaporized resin from air and
CO2 from burnt resin. Resin will contain rare lunar
elements like H, C and N, and we cannot afford to waste
these. If we cast in chambers with inert gas filled interiors
the resin won't burn to form CO2 and other gases.
If we can synthesize clay on the Moon,
and i suspect that we can and must, and do it cheaply,
then we could even work clay and fire it with electric
furnaces into pottery and other desirable items. That
would be a nice added benefit. An unconventional
approach to metal casting on the Moon might be the use
of microwave sintered regolith molds, but data is lacking.
This should be investigated.

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-Casting Metal on the Moon
 Engineering details might seem dull or trivial, but
 they can make or break us. There won't be any ISRU and

Sand Casting - Revision history

Strangelv: Strangelv moved page Sand casting to Sand Casting: Capitalization

Dietzler at 14:54, 2 May 2012

Farred: adding category

Dietzler: Created page with "Casting Metal on the Moon By David Dietzler and posted by author. Engineering details might seem dull or trivial, but they can make or break us. There won't be any ISRU and boots..."