LAST-A-FOAM® FR-4600 microcell polyurethane foam supports the most intricate detail while eliminating extra prep work. With an even-smoother surface finish than our LAST-A-FOAM® FR-4500 material, it is superb for precision tooling applications, or as modeling foam. Advanced microcell technology creates a grain-free, ultra smooth exterior for painted finishes, significantly reducing process time. What's more, its finer cell structure is comparable to higher-density products without the added cost and weight. Unlike more dense glass microballoon-filled syntactic foams, this material greatly reduces tooling wear. The high-density foam is easily worked using CAD/CAM routers and CNC machines - or the simplest woodworking tools. The FR-4600's exceptional machining characteristics also make it an efficient material to create intricately patterned masters for composite and layup tools, and for mold and foundry patterns.