used with or without a catalyst and with or without an inhibitor it is contemplated that known catalysts and or inhibitors such as are taught in the above cited patents of vu et al are suitable for optional incorporation in the method herein polyurethane catalysts include tertiary amines tin compounds or other metal organics polyurethane inhibitors include organic and inorganic acids such as benzoyl chloride p toluene sulfonic acid formic acid acetic acid benzoic acid phosphoric acid hydrochloric acid and the like further exemplary methods of the invention involve the use of a proportioning pump 16 which meters components a and b in desired ratios the metering pump 16 can be of either the piston or gear variety preferably a mixer 18 is used in conjunction with the proportioning pump 16 to ensure that the thermosetting components 12 and 14 are sufficiently intermixed prior to extrusion 20 so as to initiate the thermosetting reaction and ensure a uniform result throughout the processed extrudate 22 two component metering and mixing systems are available for processing low to medium viscosity materials such as the preferred two component polyurethane systems described herein it is believed that the amount and nature of catalyst used if any will be within the abilities of those ordinarily skilled in the art to ascertain without undue experimentation generally this will depend upon the thermoset components chosen the rate or rates of volume output of the proportioning pump 16 the volume throughput of the.