Casting Patterns and Metal Casting Information

by : Kent Klein

Metalcasting is a useful skill that has its roots in antiquity. Weapons andsculptures were traditionally created using this method but as the DIY movementgained momentum many modern day casters have found a use for metal casting tomake plumbing fixtures, door knobs, and many other items. Today, smallfoundries can be found in many backyards, garages, and workshops.In order to make a casting of metal, you will need a furnace capable of meltingmetal alloys at high temperatures. Usually, individual metal casters willconstruct their own furnace. There are companies that will sell small scalefurnaces but they are often costly. The most common type of casting is calledSand Casting which uses sand or green sand to make the molds where the moltenmetal will be poured into to form the finished product. The mold is a handmadeitem placed in a flask which has two parts, a cope and drag. The mold isusually made of sand, but can also be created using other ingredients likelatex or even metal. It is in the mold that you will set the pattern to formthe mold cavity. The mold cavity will be an impression of the pattern including the fine detailswhich will then be filled with the molten alloy. Pattern casting is an art formin itself, really, but anyone can create a pattern even if you have no artisticskill what so ever. The pattern is an original which will be cast into metal.Common pattern castings include complex engine parts for models, replicas ofCivil War era weapons, sculptures, and even jewelry.The pattern can be made of any material like clay, wood, and wax. The patternmaterial really depends on a few factors like the casting method and theavailability of the material. If you are able to carve wood then you can usethis skill to make patterns. There are some casting methods that call for thepatterns to be made of certain materials. An example of this is the Lost WaxCasting Method which will use wax as the pattern.When creating the mold, you will place the original into the drag of the flaskand place more molding material on top forming the cope. When the mold is dryyou will carefully remove the pattern revealing an impression in the mold. If you are creating your own pattern you will need to make it with Contractionallowances in mind. This contraction allowance will compensate for theshrinkage that occurs in many casting processes. In order to take out thepattern without disturbing the mold, draft allowances need to be considered aswell. The pattern should have tapered edges to allow for easy removal.Many who make their own patterns will add sprues, gatesFree Reprint Articles, and risers to thepattern so that when castled these items will already be in the mold.?These devices will allow the molten metal to find its way into the mold cavity.If you find it difficult to make your own patterns then you can pay for patternmaking services; although many casters in the same situation will just learnhow to make patterns to save money. Pattern casting is a valuable skill to haveand can be learned rather easily.