Nu-Wood Decorative Millwork

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 planned 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.