So here is another fine mess. Here you see a close up and a big picture of the vertical tail that I am working on. This material X-30 combines two liquids and the reaction between the two is an expanding foam which hardens like a rock pretty quickly. At first I thought it would be use to attach the blue foam to the ribs. Then I thought it would be a good material to even out the foam and fill in the gaps. Well none of that has worked very well. The foam expands wonderfully. In fact I don't know why the foam isn't used to just fill in the whole section between the ribs. But anyways it does not spread very well at all. I poured it into some holes and it expanded and filled the holes, but spreading it to make a smooth surface just did not work. So I ended up with some very lumpy application which when attempting to sand it down to a smooth surface doesn't work because it just cracks off the foam. You can see on the close up where I tried to create a smooth layup of this material, but it just clumps together like lumpy soup and gets more uneven not less. At this point I am thinking of ripping out the blue foam and using just a dab of X-30 in a few spots. But I don't know yet.