I then cut the oil door out to accept a Hartwell Latch. I spent a little time making a template for the latch before I dove into cutting on the real thing!

I taped the oil door back in place in anticipation of fitting the hinge mechanism.

Here is the hinge mechanism drilled and clecoed in place. I suppose a person could build such a hinge, but I just decided to buy it from XXXX. It was $XX, but it saved me some serious jacking-around time. At this point, I'm wanting to get this thing in the air and if spending $XX for a pre-fabbed part moves me towards that goal, then that's what it's going to be!

I'm planning to use fiberglass to mold in a flange for the door to rest on so I needed to remove a bit of primer to make sure the new fiberglass would stick to the cowling. I used blue masking tape to protect the door while I sanded off the primer where the fiberglass would be applied.

Here, I've applied 4 layers of 6oz. cloth around about 80% of the perimeter of the oil door. I used peel-ply to minimize the amount of sanding I'll need to do.

Also of note is that I mated the upper and lower sections of the cowling along with the right cowl cheek to make sure the cowling was in its proper shape as the flanges cured. The whole idea of using fiberglass instead of aluminum for these flanges is that the shape is a bit complex--with compound curves and all that.

Here's what the flange looks like with the door installed and the cowling back on the airplane. Of course, I'll trim the flange back to a uniform 1/2", but I think this will work very well.

This is what the door will look like in the closed position with the hidden hinge system. I guess, it would have been just fine to have a few inches of piano hinge showing, but I still like the "trick" nature of the hidden hinge system. The slight additional cost in terms of time and money were worth it to me!