James: I believe Delmat is a proprietary product. Check with some of the solder fixture fabricators in the archives.
Continuing, I would not select knowingly Delmat as a board stiffener. It's a composite material similar to oriented strand board (over at Home Depot). More often than not, I see metal strips being used as board stiffeners. One source is: Circuit Components 400SrooseveltSt TempeAZ85282 602.967.0624fax9385