A pretty good profile shot of where I'm going with this. I tried to match the general look of the aft 4-6 inches of the tunnel. I ended up changing the radius of the curves, but just slightly.

I should have done this at the outset. I cut a template out of 1/2" particle bard to define the shape of the tunnel as it exists just below the spinner.

I built up the tunnel using Bondo to match the particle board template. I'm not sure if I mentioned it in previous posts, but I added talcum powder to the Bondo to improve its sanding characteristics. According to tribal knowledge among RV builders, the talcum powder is what makes the higher quality fillers so easy to sand. It seemed to help the Bondo. Of course, I'd never use Bondo for anything that would remain on the airplane, but it's a pretty cheap alternative for these molds.

A few rounds of additional filler and additional sanding left me with a pretty nice mold.

After the Bondo had been sanded as best I could, I painted the mold using spray can gloss white paint. My thought was that I wanted a relatively nice surface for the layup, but I didn't want to spend a bunch of time or money getting it done.

The green you see in this picture is PVA mold release. I waxed the mold first with some paste wax and then sprayed several coats of the PVA mold release.

I used 4 layers of 6oz. cloth on the layup. The last coat is peel ply. It doesn't do compound curves very well so I had to give up on getting it to lay down smooth over the entire surface.