Rapid Prototyping involved creating a working model of various parts of the system at a very early stage, after a relatively short investigation. The method used in building it is usually quite informal, the most important factor being the speed with which the model is provided.
There are water-and solvent-based -- also called oil-based -- polyurethane varnishes. Water-based polyurethanes are more environmentally friendly and safer to use than solvent-based, but they are not as resistant to wear and tear as solvent-based products.
Waterbased Acrolon 100 Polyurethane. WATER BASED ACROLON 100 URETHANE is an advanced technology, VOC compliant, water based, acrylic urethane. Provides performance properties comparable to premium quality solvent based urethanes. This is a high gloss abrasion resistant urethane that has excellent weathering properties. 1  Retains its appearance over a wide range of chemical, weather, and mechanical conditions. 2  Can be applied directly to water based and solvent based organic zinc rich primers. 3  Low odor.  Non- 1 flammable. <100 g/L 2  VOC. HAPS  Free.