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.
The resin and isocyanate meet, react, and create a very durable polyurethane coating as they proceed to dry quickly. Next we can compare relative performanceâ¦. This is best described as âAlkyd is better and Urethane is best.â Alkyd coating is a very good choice for industrial and low-end transportation applications. Urethanes are used on high-end trucks, buses, trailers, and automobiles. Finally, along with these variables come relative differences in price.