Experimental results are given for several nondestructive tests designed to measure the resin to glass ratio, to measure thickness, and to locate voids. The measurement of back-scattered beta particles using a radioactive source show promise for monitoring the resin to glass ratio especially as an in-process control. Two methods of measuring the thickness of nonmetallic materials are discussed and the results of thickness measurements in the range from zero to 3 in. are given for an eddy current “lift-off” measurement method and for a capacitance measurement method. Both of these methods measure thickness from one side only but both require a metallic conductor on the other side. The “corona method” is described and its use for the detection of voids in resin-glass structures is discussed. Experimental results are given showing the size and location of voids which have been found.