Follow up to the earlier post: The actual thickness of the rock shield material is 1/16", I don't know why I ordered 1/8" but that's what I got. Turns out, there's enough movement in the flexible shim material that 1/8" will work, so all's well. The polyethelene sheet has a static electric characteristic I don't like, seems odd bits are attracted to it. But it's going to stand up well to the bugs and UV, I think. Maybe not my first choice of replacement material, but I ordered online. The frame went back together just fine, I think it's required to remove the section of the frame to do this work, especially with 1/8" material, and since the upper section is also the hinge, good solid rivets are needed for reassembly. Possibly small bolts could work, but I think that's a poor second choice.