A waterjet is a tool used in machine shops to cut metal parts with a (very) high-pressure stream of water. As amazing as it sounds, if you get water flowing fast enough it can actually cut metal. Think of a waterjet as something with about 30 times the pressure of the power washer wand at your local car wash. Power washing at car washes is an everyday example of a dirt film being "cut" off the body, wheels and tires of an automobile.

The key to cutting metal with water is to keep the spray coherent. Waterjets are able to cut because the spray is channeled through a very narrow jeweled nozzle at a very high pressure to keep the spray coherent. Unlike metal cutters, a waterjet never gets dull and it cannot overheat. Low pressure waterjets were first used for mining gold in California in 1852. Steam and hot water jets were used in the early 1900s for cleaning. High pressure waterjets were used for mining in the 1960s, and about 10 years ago industry began using waterjets for cutting. Abrasive water jets (abrasivejets) were first used in industry in about 1980.

Most people have seen the end results of corrosion on a number of appliances, vehicles, and other items that included metal components. But what is corrosion and how does it develop? Here are the basics of how corrosion begins and what can be done to prevent corrosion from ruining valuable items.

Corrosion is a process that takes place when essential properties within a given material begin to deteriorate, after exposure to elements that recur within the environment. Most often, this deterioration is noticed in metals and referred to as rust. What happens in this case is the chemical reactions that are set up by an exposure of the electrons in the metal to the presence of water and oxygen. As an example, a tin roof is exposed to the wind and the rain.

Metal sculpture has a long history and developed independently in many parts of the world. Bronze has been the metal used most often in creating sculpture. Metal sculpture differs from stone or wood sculpture in that it is generally an additive, rather than a subtractive, process. Metal can be melted and poured, heated and fused, hammered or riveted to create sturdy, long-lasting works of art.

Oldest Examples

The oldest surviving metal casting is a copper frog from 3200 BC cast in Mesopotamia. Amsuvarna, ruler of Nepal, ordered a metal crest for Changu Narayan Temple in 607 AD, and at least one Bronze Buddha from that period survives, according to the Spiny Babbler Museum of Nepalese Arts. The Egyptians and Sumerians were casting metal for weapons, tools, coins and decorative sculpture by 3500 BC. Written records show the Greeks created more statues from metal than from marble; sadly few examples survive because metal sculptures are often melted down in times of war to create weapons. The Zeus of Artemisium (c. 460 to 450 BC) can be seen at the National Museum in Athens, and The Delphic Charioteer (c. 470 BC), at the Delphi Museum.