Casting and Moulding
Foundry techniques for schools
Head of Craft, Design and Technology Faculty,
Ashleigh School, Sheffield
Heinemann Educational Books
Backing sand Sand which is used to fill a moulding box after
the facing sand has been applied.
Bottom-part box Sometimes called the drag, it is often the
first part of the mould to be rammed and usually contains the pattern.
Casting A casting is produced when molten metal poured into
a mould has cooled. It is also the term used for pouring the metal.
Cope See top- part box.
Core A core, usually made from sand, is used to form an
internal shape in a casting. The core protrudes into the mould
and molten metal flows around it. When the metal has
solidified, the sand core can be removed leaving the required internal shape.
Core box A box in which a core is made.
Core print An extra piece of material added to a pattern that
leaves a cavity in the sand into which a core can be located.
Cover cores Sand cores made from core boxes to ease the moulding process.
Dies Permanent or re-usable moulds, usually made from either
plaster or metal, used for producing castings.
Dowels Cylindrical pieces of timber which can be used to
locate split patterns or core boxes accurately.
Downgate A hole in the sand down which metal is poured when casting.
Downgate peg Sometimes called a sprue peg it is used for
producing a downgate.
Draft See taper.
Drag See bottom-part box.
Facing sand To enable a smooth surface to be produced on a
casting, it is advisable to cover the pattern with a layer of fine
facing sand, before filling the moulding box with backing
Fillet Forms a radius on an internal corner to avoid the
possibility of the casting being weakened when the metal cools.
Finishing On castings, the finishing process can be divided
into two sections:
1 Fettling, which means the removal of the downgate,
risers, and runner bar.
2 The desired surface finish, which can be obtained by wire
brush, files, or machines.
G cramp Adjustable tool for holding parts of woodwork
together during assembly.
Greensand Moulding sand which uses water and clay for
69Hand rammer A moulding tool which is used to pack sand
into a moulding box.
Hot wire cutter Equipment used for cutting polystyrene by
means of a hot wire.
Jointing down A moulding process used for irregular shaped
Lugs Parts of a moulding box which carry the locating
attachments (usually holes and pins) .
Match plate A device used to eliminate the jointing down
Mould Molten metal is poured into a mould to produce a
Moulding box A box, sometimes called a flask, of either metal
or wood, which is designed to hold the sand when making a
Mould cavity A cavity left in the mould after the removal of
the pattern and into which the molten metal is poured.
Moulding sand This sand is used for making moulds, and is
bonded by water and clay, oil or resin.
Moulding trowels There are several varieties of these trowels
which are used for shaping sand when making a mould.
Oddside A technique which eases the jointing down process
when several moulds are to be produced.
Parting powder A fine powder which is dusted onto rammed
sand to prevent another layer sticking to it, between top and
bottom-part boxes of a mould for example.
Pattern A former, usually made from wood, metal, plastic, or
polystyrene, which is used to produce a casting. It forms a
cavity in sand into which metal is poured.
Pattern plate A plate onto which patterns are fastened to
ease the moulding process.
Pins These are usually fastened to the lugs on a moulding box
and are used to locate the two parts of the mould accurately.
Plaster A liquid which sets into a solid that can be used for
patterns or moulds.
Polystyrene patterns A pattern made from polystyrene is not
removed from the mould before casting. The pattern is burnt
out by the molten metal during casting.
Pyrometer An instrument which measures the temperature of
Rammer See hand rammer.
Rapping Tapping the pattern gently to ease its withdrawal
from the mould.
Rapping and lifting plates Small plates, usually made from
metal which are inserted into patterns to assist their withdrawal
Riser A hole in the mould which has the functions of allowing
gases to escape and enables the person pouring the metal to
gauge when the mould has been completely filled. It is also
used to provide a pool of molten metal which will compensate
for the normal loss in volume which occurs when a casting
Riser peg A peg used to form a riser cavity in the mould.
70Runner bar A channel along which molten metal flows from
the downgate to the mould cavity.
Safety jacket A wooden sleeve placed over a mould, to
prevent accidents when pouring molten metal. Its most
common application would be when casting projects not
supported by moulding boxes (for example when stack
Scratch vents Where the riser does not provide adequate
ventilation because of the shape of the casting, a secondary
form of venting will be necessary. A scratch vent is a shallow
channel made in the sand.
Snapflask A moulding box which is hinged at one corner and
can be snapped away from the mould.
Split pattern To simplify the moulding process, by
eliminating the need to joint down, a pattern can sometimes be
split, often along a centre line or at its widest point.
Stack moulding A process used for making more than one
casting. Moulds are stacked on top of each other and cast
Strickle A straight bar which is used to remove excess sand
when ramming is finished.
Taper Sometimes called draft, it is used to allow the pattern to
be withdrawn from a mould cleanly.
Top-part box Sometimes called the cope, it is the uppermost
box of a complete mould.
Vents Ventilation holes or channels used to allow gases to
escape from the mould.
1 box sides 2 riser 3 vents
4 downgate 5 sand ledges 6 locating pins
7 joint line
8 runner bar 9 mould cavity
11 riser base
Fig. 1 Cross-section of a mould
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Casting and Moulding