What are polyurethanes and polyesters?
Polyurethanes are a versatile family of quick-setting resins which produce high-quality, long-lasting, and stable castings. They differ from polyesters (“fiberglass” resins) in both their greater cost and in their greater structural strength and chemical stability. Polyesters are most commonly utilized to produce hollow castings where the excessive weight or cost of a solid object may be a consideration . . .
