Take 2, I've started my cardboard, fabric sandwich, but the middle layer needs to cure before I add the outter strips. I put this one under some weight this time so it would hold together. I took the cardboard only failure from last time and tried giving it a bath in some resin. I did this with a raw piece as well. It looks like they will only be strong in one direction, perpendicular to the corrugations. I used a lot less hardener so I hope the resin gets pulled into more of the fibers in the cardboard. The last test was mostly to use up the resin I had mixed for the cardboard dipping of the previous 2 tests. I applied fabric to a strip of cardboard while it was all in the resin dip. There wasn' much left and this used most of the left overs up. I put this last one under some weight to cure as well. Once it's all completely cured for at least 24 hours, I'll do another stress test on the three pieces I bathed in resin. I'm going to try and go easy because I want to add another layer of fabric to the fabric one, and see about using the two raw pieces I dipped to make another fabric sandwich with them. I still need to complete the non dipped cardboard fabric sandwich as a comparison. If I need to dip all the cardboard, I'm doing to need to find something bigger than 9x18 (but not too much), and I'm concerned about using the right resin for something that large. The bondo stuff I'm using now was cheap, readily available, and only to give me an idea of how it would react to the cardboard. I'm not sure if there is something better. If there is, then I need to see if it's cost effective.