Building and Installing Roof Ventilation Bezel

Because the top of the camper is curved, a bezel is added to create a flat area for mounting a ventilation fan.  This shows the bezel upside-down after assembling. 

The joints are filleted followed by the addition of fiberglass cloth and epoxy.

 And here is where I ran into problems.  The cutout hole is almost too big for the bezel!

From beneath, you can see that I did not cut it larger than the precut slots.  In fact you can see the parts of the slots that are left after I ran the saw down the middle of each of them.  My advice to future builders is to cut the opening a little too small--just inside the slots or even a little smaller.  It is much easier to widen the opening later to fit the bezel.  But that may not be necessary as the mounting for the ventilator will probably cover the edge up anyway.  The manual does not call for stitching wires, but holes were pre-drilled so I used them.  The bezel just barely covered the opening in some parts, but with the wires I was able to keep it in the right place while I glued and filleted.  Rather than apply thickened epoxy to the bezel first, I stitched it loosely, applied the epoxy, and then tightened the wires.  With the fillets and fiberglass cloth on both sides it should be plenty strong.  (I hope so because the bezel has to support the camper later when I turn it back upside-down for more work.)

Here's the bezel after I applied the thickened epoxy.  I cleaned it up pretty well after this, but didn't shoot a picture.

Oh wait, yes I did.  After it cured I removed the wires and worked on the outside.

And here it is filleted and fiberglassed. A hole will be cut in the flat top to accommodate a ventilation system.