Anyone have a good supplier or some knowledge of very high density polyurethane boards used for creating composite one off tooling. Been looking around and can't find a good source or much usable info. Have been doing CNC to one off tooling experiments lately. As the tools get large the material costs add up in a hurry or the labor. Current method is to use 2 lb blue foam from lumber yard attached to MDF for stability. Then cut mold cavity directly with CNC with one pass to within a few thousandths. Then sand out the ridges and coat with bar top epoxy. That is working really well but the epoxy part is hard to control properly. We wet sand at the end to get a reasonable tool. I paint them and spot putty and fix up what wasn't happy. Would like to up the quality and streamline the process. Some of the tooling board products look nice but look gawd awful expensive for what they are. With my router I can get 48" x 48" x 6" deep in one pass. Those panels can be combined into any larger structure. Currently working on a large wingspan UAV and developing guerrilla methods. Going well but could go better. Learning a ton about using Fusion360, MACH3 for CNC OML direct carving for aero structures. You have to be really clever with CAD before you can even start this sort of process. That is where the magic happens.