weather spotter- If my first idea doesn't work I'll probably have to end up going your route. I may also eventually drop my goal of having hatch functionality because this thing is HEAVY and I don't think it's going to be easy to seal this gap and allow the hatch to be open and closed. As far as the wrinkles in the coroplast goes, I'm not really sure what the negative of having those is besides appearance?
euromodder-I may have to take a trip up to the autoparts store and see what the have, but in some places where the body panels switch over, the gap becomes as 1" high so it's very hard to find something that will work.
Cd- I may have the add a daytona type spoiler to get the last 12 inches of my boat tail to line up with the template. I'll see what tuft testing tells me, but for now I'm not worried about it.
Here is a photo of the process I'm using to seal the gap. The metal part is 3 inch wide 26 gauge galvanized steel that is bent at a angle so the the leading edge touches the body of the car. Then, I added 1/4" rubberized foam weatherstrip to protect the car's body and allow the metal to make better contact with curving body panels. There are still some gaps, so I'm hoping my metal pieces don't become huge metal air flaps when I get up to highway speeds.
Here is a photo of the process I'm using the seal the gaps between coroplast panels. On the left is what the seam used to look like. On the right is what it looks like after I'm done. The finish should be better after I paint the tail. The technique is being called "heat gun viola"
Steps:
1. Prepare "Heat Gun"
2. Power on Heat gun and point at seam.
3. As coroplast begins to flex, bubble up, and melt pull heat gun away
4. As soon as possible, press a flat sheet of metal against the seam.
5. Let cool and...
6. "Viola!" a smooth water tight seam.
Oh, I also checked out my tail lights for the first time at night. All I can say is WOW! I'm sorry for whoever pulls up behind me because these are BRIGHT. I may add lights on the mirrors because from behind I appear narrower than I actually am.
Tail lights in action. I have the blinkers flashing for effect