Shop for High Density Urethane (HDU) Boards. High density urethane foam board also known as HDU board is used for hand-carved signs as well as CNC-machining. RAKU® TOOL Styling Board (SB) has a fine surface structure and lends itself to both manual and mechanical processing. Precision Board Plus™ High Density Urethane (PBLT) is a “closed cell” rigid polyurethane product made specifically for applications of up to 200° F continuous exposure. High density urethane is available in a range of sheet sizes, thicknesses and densities, and can be cut or bonded into a variety of shapes for final machining or shaping. Stocked products typically ship in 2-5 business days. Can’t find what you need? Get a quote.