For those who prefer to view a slideshow of how the work progressed, CLICK HERE
My first step was to measure the thickness of the roof, which was .050". I had some .060" Evergreen sheet styrene handy, so I flipped the body over, placed it upon the styrene sheet, and traced the roof opening with an Ultra Fine Sharpie marker.
I then cut out the patch piece and beveled the edges slightly, making it narrower at the bottom (inside) edges so the piece could not fall inside the body. I also tapered the roof opening to match, and kept slowly filing and test fitting the patch until I was satisfied with the fit.
Since the roof has a slightly convex shape to it (viewed side to side), I added a slight arch to the patch to match the roof's curvature. Once satisfied, I used CA glue and accelerator at various points around the perimeter to tack the patch panel in place. Finally, I ran a full bead of CA glue in the joint all the way around the patch panel, then hit it with more accelerator. The patch was now permanently in place.
Next, I needed to sand the patch panel even with the rest of the roof, so using 320 grit 3M wet sanding paper and a rubber sanding block I started sanding, making sure to not get too close to the drip rails.
Once I had the panel mostly even with the surrounding roof, I applied another layer of CA glue and accelerator to the gap, just to make sure it was completely full and the roof would be perfectly smooth. I sanded again with 320 grit paper, then switched to 600, then 800, and checked my progress, but found three low areas (circled in blue):
The low spots were so shallow I made with a few passes again with the 320 grit paper and the low spots were gone, so back through the 600 and 800, and this time I finished with 1000 grit paper for a very smooth finish.
I ran my fingernail perpendicular to the joint, all the way around the patch panel, just to be sure there were no voids nor low spots, and found none, so the roof is now done.
Next step, reducing the size of the rear wheel openings and adding back in the body character line. You can see how enlarged the openings are now:
Edited by Casey, 30 January 2011 - 04:30 PM.