Alumina Type ZAL-45AA Characteristics & Properties Continued To Order Standard boards: order online or specify quantity, item # and description. Standard boards are available for immediate shipment from stock. Standard tolerances for boards are +/- 1/8” on length and width and +/- 1/16” on thickness. Custom boards as large as 24”W x 36”L x 2”T have been manufactured. Custom shapes: our state-of-the-art tight-tolerance machining techniques allow a wide variety of sizes and shapes to be made. Surface treatments including rigidization with colloidal alumina (AL-R/H) or colloidal silica (SI-RIG)...