Lost wax jewelry casting is one of the oldest forms of intricate fabrication known. Before the pyramids rose in Egypt people were making jewelry by the lost wax casting method which is still in use today. The advantage of the lost wax casting technique is that you can work details into a piece of metal by this technique that could never be simply carved or worked in by normal methods.
In theory it is a simple technique. First a model of the desired piece of jewelry is made out of wax. Then the wax is covered by one of a number of substances such as clay or plaster, leaving only a small hole.
When the outer covering is hard or dried, the entire thing is heated to a temperature high enough to melt all the wax. When casting jewelry, a light weight kiln may be used that may have an average temperature of 400F to 800F.
A typical commercial lost wax investment casting de-waxer may have average temperatures from 1800F – 3000F depending on the size.
The wax is literally burned out of the mold through the hole, which is why it is called ‘the lost wax process.’ What is left at this point is a hollow, mirror image of the original casting.
Now that the wax is gone, molten metal is poured through the hole into the hollow left where the wax existed. Once the metal has cooled and solidified the mold is broken.
The metal piece is now an exact duplicate of the wax original.
In modern jewelry making a single model is usually made of jeweler’s wax, which is particularly suited to carving of fine details.
It is rare to create a single model for large commercial general sales unless it is designed for a unique operation.
When creating commercial investment or precision castings, a die is created from a Tool and Die expert. This die is the reverse image of the finished product and is what receives, has ‘invested into it,’ wax that will allow someone to recreate many models in a short time.
These dies are relatively expensive and have a limited life since the precision of each detail must remain identical throughout each wax investment. However, in a commercial lost wax investment casting business, a proper tool and die method helps keep costs down while quickly replicating many finished castings.
Although the technique of lost wax jewelry casting is usually described as above, and used to make unique pieces, it is also possible to use a mold to make the wax piece. This enables the casting expert to create several identical pieces at one time by casting the wax object itself in a reusable mold.
While there are modern refinements and improvements in investment casting, the lost wax casting methods have roots that go back to the original Egyptian jewelry productions and remain in process today.
C.L. Hendricks has been a Jill-of-all-trades and become an expert in some. She writes for http://www.shelmetcastings.com and http://www.survival-homestead.com, as well as several other websites on a variety of topics.
Article Source: UnArchived Articles
|
