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.
Ultra Low VOC Contact/Brake Cleaner. Quick-Drying Solvent Leaves No Residue. Original Ultra Low VOC Contact/Brake Cleaner is a highly active solvent blend which provides maximum performance in a brake parts cleaner without the use of ozone depleters or chlorinated solvents.