We offer three categories and a variety of sizes for our Matrix Board Material. Used to create molds for rubber stamp dies from your master plates. Available in various sheet sizes or can be custom cut to meet your special applications. Uncured shelf life is six months. Thickness and sheet size dimensions are approximate. TRADITIONAL BAKELITE MATRIX -- A soft, fine grained molding material designed for molding at various pressures in all vulcanizers with temperatures of 300 degrees F. Works extremely well with lead type and art stamps pressed from magnesium photoengravings. Releases with Silicone Spray Release Solution. Is soft and easily formed, but durable enough to provide hundreds of stamp dies. No. 99 thickness is about .140" - .150". B3 thickness is about .210" - .220". EXTRA DEEP MATRIX -- Get exceptional relief from magnesium master plates. This super-soft material conforms to every detail of the original. Mold from 16 gauge, 11 point and 1/4 inch magnesium photoengravings. Releases with Silicone Spray Release Solution. Hundreds of rubber dies can be formed before replacement is necessary. Overall thickness is approximately .270" - .280". LOW DENSITY MATRIX -- Designed specifically for molding from photopolymer plates. Extremely durable. Releases with Graphite Spray Release Solution. Overall thickness is approximately .160" - .170".