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Nu-Wood Decorative Millwork is millwork made of a specially formulated polyurethane polymer. The standard density is similar to white pine. It can be cut, sawn, shaped, routed, nailed, stapled, and screwed just like wood. Profiles exist for a variety of uses, indoors and out. Advantages over wood include a surface which will not crack, flake, or blister and a product which is resistant to water, mold, mildew, and insects. ==Manufacturing process== The polyurethane foam is created from two components which generate heat when combined. One component contains water and the other component reacts with water. The oxygen of the water fuels the exothermic reaction, leaving hydrogen bubbles which causes the compound to foam. Given no compression, the foam rises to fill the space allowed. Based on the mixture and the specific makeup of the two chemicals, it is possible to estimate exactly how much foam is required to fill a given space. More importantly, it is possible to determine the exact amount of mixture required to fill a defined space and achieve a specific packing ratio. Tremendous compression is required to obtain packing equal to the density of white pine. In addition, fake wood needs a wood look and feel on the surface. This means the finished product must easily slide out of the mold that provides its shape. It also means the mold must be strong enough to withstand the pressure of the expanding foam. This combination of requirements creates a complex problem that is solved by a variety of techniques. Silicone rubber is used to create negative space molds from original millwork created by expert woodworkers. The forms are polished, painted with a release agent surrounded by a box made of angled aluminum and filled with the liquid silicone rubber compound. The rubber is generally around one inch thick. Once the rubber hardens the form is removed from the standard, which is shelved for future use. At this time, the form provides a negative space with the exact dimensional and surface characteristics of the woodwork to be produced, plus a small tolerance for expected shrinkage. The rubber form and form box pass along a bed of rollers to a paint shop where the rubber form is covered with a thin veneer of water-based paint. The heat and pressure of the expanding foam cause the paint to transfer to the finished piece. The paint protects the rubber form from the chemicals in the polyurethane and provides a release from the piece. While the finished polyurethane product is quite light, consisting largely of closed cells of hydrogen, the rubber form and the metal and wood foam box are very heavy. The manufacturing process is difficult to automate due to the many shapes and sizes and the fact that most orders are unique. Thus, the work requires great strength and is quite hazardous to the back, hands, and feet. Competition produces pricing pressures, and labor is the most expensive component of pricing. As a result, low wages are standard. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nu-Wood Decorative Millwork」の詳細全文を読む スポンサード リンク
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