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.
Overview. MinwaxÂ® HelmsmanÂ® Spar Urethane is specially formulated as a protective clear finish for exterior or interior wood exposed to sunlight, water, or temperature changes. 1  Contains UV blockers to reduce the sun's graying and fading effects. 2  Forms a protective barrier against rain and moisture.elmsmanÂ® Spar Urethane. Tweet. MinwaxÂ® HelmsmanÂ® Spar Urethane is specially formulated as a protective clear finish for exterior or interior wood exposed to sunlight, water, or temperature changes. Contains UV blockers to reduce the sun's graying and fading effects.