This is intended to explain
a lot of the jargon used in a foundry.
Whether it is a backyard affair or a commercial foundry, a cupola or an
induction furnace, it helps if we all call things by their right
A combination of metals melted together.
A device used as a valve for air. It works similar to
a gate valve.
A device for mixing fuel with air to
form a burnable mixture with the aid of a fan or blower.
A device for mixing fuel (usually propane) with air to
form a burnable mixture without the aid of a fan or blower.
A quantity of metal, usually about to be melted.
Part of a flask used when a deeper
flask is needed. The cheek is an additional section of flask and goes
between the cope and drag.
Computer Numeric Control. The term
used for the motion control interface used to drive machine tools with
a personal computer (used mostly in hobby tools) or a dedicated
electronic controller (used mostly in commercial machines). CNC milling
can be used for pattern making. There are also CNC controlled hot wire
cutters for foam.
Casting defect where two or
more streams of molten metal meet in a mold, but fail to weld together.
Caused by pouring too slow, or too cold. May also be improperly
designed gates that won't allow the mold to fill fast enough.
The upper part of the flask when it is in pouring
position. (Cope and
The act of digging away sand in the cope after ramming
to expose the parting line of the pattern.
A device (made in the foundry or
bought from a foundry supply) for leaving voids in a casting that would
otherwise be impossible to mold. For example, a cylindrical shaped core
to leave a hole for a shaft.
A device of refractory material shaped to hold metal
as it is melted and poured.
The act of removing absorbed gasses from the melt,
such as adding a degassing agent.
Casting using a permanent mold (a die) and forcing the
molten metal into the mold under pressure.
The taper of a pattern to allow it to be removed from
the sand mold.
The lower part of the flask when it is pouring
position. (Cope and Drag)
1. The act of removing a pattern from the sand mold.
2. A sketch or print that gives the dimensions of a part.
Impurities on the melt that must be removed by
skimming before the pour. Slag.
See Flask, English.
New or very good bank sand that is riddled (sifted) onto the
pattern before bank run sand is packed in the flask.
High temperature bricks with a fusion point not less
than 2876 degrees F or 1580 degrees C. (note 1)
Clay with a fusion point not less than 2868 degrees F.
A device usually shaped like a box
without top or bottom and separated into two (or more) halves, a cope
and a drag. It is used to hold the molding sand around the pattern as
it is rammed.
A flask that is designed to be stood on end and poured.
A flask that has hinges on
one corner and latches opposite that allow the flask to open after the
mold is rammed. The same snap flask can then be used for the next mold
allowing you to make many molds at a time with just one flask.
Devices for concentrating heat to achieve melting
A tunnel in the sand mold connecting the sprue and the
A mixture of fine sand, bentonite clay and water.
Hot wire foam
A device used to cut foam for pattern making. Usually made
electrically heated resistance wire. (Ni-Chrome, Kanthanal, Guitar
Casting defect where foreign material is included
into the casting, such as a sand inclusion.
Parts formed of a second material
placed in the mold before pouring, such as a steel pin that is required
to be bonded to an aluminum casting. (note 1)
A jacket is a wood or metal frame
which is placed around a mold made in a snap flask during pouring to
support the mold and prevent a run out between the cope and drag. The
common practice is to have as many jackets (for each size snap flask)
can be poured at a time. ….. The jackets must be kept in good shape and
fit like a glove. (note 1)
An oil bonded sand similar to petrobond, but mixed by
the user from individual ingredients instead of purchased readymade.
The practice of adding depth to a pattern in areas
where the casting will be machined.
A device that fits between a
cope and drag and mounts a pattern. The pattern is split at the parting
line and half mounted above and half below the match plate. It is also
common to have the gating system on the match plate. The purpose is to
allow faster ramming of molds for a repetitive pattern.
A device used to form molten metal to a specific
shape. For example, the rammed sand inside a flask.
Flat board used under a flask when ramming, thick
enough not to spring as the sand is rammed.
A mixture of fine sand and binder that when packed
will hold the shape of a pattern.
The process of coating sand with clay via a smearing
action as well as mixing.
A device that mulls foundry molding sand.
Abbreviation for Naturally aspirated.
Regarding burners, naturally aspirated generally means there
is no blower to force air into the burner. See also Burner...
Oil Bonded Sand
A mixture of fine sand, bentone clay and oil that will
pack very hard. also called Petrobond, K-bond.
A powder that coats the surface of an
object so that the molding sand will not stick to it. This allows a
pattern to be drawn from the sand and leave a clean, sharp impression
behind. Parting dust also coats the sand in one half of the mold and
prevents the sand in the other half from sticking to it. This allows
the halves to be separated and the pattern removed. This separation
line is called the parting line. (Shamelessly stolen from Budget
Casting Supply's on-line catalog). Old books talk about using rafter
dust. An old sock makes a good dispenser. Shake it to release the
parting dust. Store in an air tight container to keep it dry. People
also use talc or baby powder.
The widest point of a pattern. The point that will
allow a mold to separate easily.
A pattern is a device used to
make the hollow cavity of a mold. It can be thought of as the positive
or original. Traditionally made of wood, it can be made of anything
that will withstand the pressure of being rammed in the sand.
Commercially available oil bonded sand.
Plinth, Plinth block
Refractory pedestal for the crucible to sit on.
A device used to measure very hot temperatures. A
thermometer with a very high range.
A tool used to pack sand in a flask.
The act of packing molding sand into a flask.
A substance that resists break down by heat.
A screen for sifting molding sand.
A riser is similar to a sprue
because it is a vertical hole in the sand. A riser is a place for metal
to go after the mold is full. Watching the riser will tell you when the
mold is full, but it also feeds metal back to the casting as the metal
cools and shrinks. Ideally, and shrink voids should be in a riser and
not in the casting. Risers should be placed at the thickest parts of
The act of removing castings from the sand mold.
Shank (or pouring
A tool for
holding a hot crucible and tipping it to pour the hot metal. Often
shaped like a ring with shafts extending from it; may have a latch to
keep the crucible from toppling out.
A casting defect where the mold doesn't fill
completely. Caused by pouring too cold, too slow or interrupted
Metals contract when
cooling and solidifying. This contraction is called shrink, and is
predictable for a particular metal. This is important when making
patterns because they must be oversize by the shrink amount for a close
Casting defect caused by lack of feed metal as the
A device used by pattern
makers. It appears to be a regular ruler, but the graduations are over
sized to make up for the shrink in the metal poured. Shrink rules are
specific to the metal being cast, due to different metal having
different shrink rates.
A method akin to ceramics
where the mold is poured with metal and almost immediately emptied of
its molten metal by dumping. This leaves a thin shell of solidified
metal in the mold. Used for making hollow castings like small statues
or lamp bodies.
See Flask, snap.
See Water Glass.
A vertical hole in the sand mold that molten metal is
Thermocouples are two
dissimilar metals welded at the end. When you heat dissimilar metals, a
voltage is generated proportional to the temperature.
A tool to grasp and lift a hot crucible from a
When you need a taller cope section
or drag section, then the flask on hand you use a frame of the required
additional depth.(note 1)
Water Bonded Sand
See Green sand.
Also known as sodium silicate.
It is a honey-like liquid that hardens in the presence of CO2. It is
used for cores by mixing with straight (unbonded) sand and packed into
a core box (mold) and then CO2 is passed through it to instantly harden
it. Alternatively, you can let it air harden, but it takes much longer.
Note 1...Information sourced
from The Metalcaster's Bible by C. W.