As we all know,investment casting
is also called lost wax casting.That's because investment casting centers on the lost wax technique of mold creation, in use for thousands of years. The wax used for these molds must have certain properties if the process is to turn out successful. The wax should be opaque rather than clear so that the artist can visualize the work; it also needs to maintain a fine balance between flexibility and brittleness. Finally, the wax must have a consistency that allows it to remain a solid while the artisan is working it. Only a relative handful of waxes fill all of these qualifications.
Basic Types of Casting Wax
Investment casting has become a very complex industry with newer waxes with a far more complicated makeup than those used a thousand years ago. However, the basic three types of wax are still as effective as ever for simple investment casting. You can purchase the three stalwarts---beeswax, paraffin wax and petroleum wax---at quality art supply stores. Beeswax is literally produced by bees, and both paraffin wax and petroleum wax are carbon-based products with the main difference between them centering on the length of the carbon chain of molecules.
Industrial Casting Wax
These waxes are a highly specialized form created from resins and petroleum products by highly complex chemical engineering. Industrial waxes fill the needs in investment casting that the simple beeswax and paraffin variety cannot meet. Use emulsified pattern wax---a highly recyclable variety---when you need an easy removal from the die cavity. Runner wax is itself a recycled wax; its main benefit lies in its strength when you need a hardier product for a more difficult casting. Use specialist wax for producing products meant for assembly. The standard and most versatile of the waxes is called a filled pattern wax because its features allow you to use it in any type of casting.
Wax for Making Repairs
Sometimes flaws occur in products made by investment casting; you can use specialized waxes to repair these flaws. For example, you can use a cream-type wax to resurface abnormalities that appear on the surface of the finished product. These types of waxes are simply called repair waxes; the primary differences between them lie in their melting points and their ability to adhere to other forms of wax.
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