A few terms of the trade:
Original – The existing piece you wish to reproduce.
Pattern – a metal, wood, or epoxy (plastic) positive representation of the original which is mounted on a board (pattern board).
Mould or Mold – a sand negative, into which molten iron is poured to make a new casting.
Sprues, risers, gates, and vents – Think of when you were younger and assembled plastic models. In model maker's terms, these items ate all of those miscellaneous pieces that the parts of your model car or plane were attached to in the kit. They also come attached to every casting, but are removed prior to shipment to you.
Core – A chemically bonded sand shape (where used) which is used to maintain full detail all the way around a casting.
Parting line – The (usually) visible line on a casting where the upper half and lower half of the sand mold come together. This line is not where the halves of the casting were “welded” together – the casting is made in one piece. Many casting defects seen in poor casting center around parting line defects.
For more information:
Architectural Iron Company
104 Ironwood Court - PO Box 126
Milford, PA 18337-0126
Web Home Page: http://www.architecturaliron.com