Portlights Installation continued...

     Sunday, May 22, I continued working on the installation of the non-opening cabin portlights.  Since these ports were not original to the Sea Sprite, and since they are built for a cored or just thicker cabin wall, I was forced to do some "creative fitting" work.  There is no coring anywhere on the Sea Sprite 23s - well the later editions ('70s) had some coring in the cockpit sole - and because of this it was necessary to build up the interior cabin wall for the ports' interior finish plate to fit snugly against.  Because of the slope in the interior cabin wall to cabin overhead transition, the ports' finish plates fit snugly against the cabin wall when mounted, but just on the sides and upper portion.  The bottom of the portlights, however, contained roughly a 1/4" gap that needed to be filled.  Filling this gap would ensure that when the finish plate was mounted to the port, the port would be pulled in tight and the port and finish plate would essentially sandwich the cabin sides.  

     The picture below is of the port side portlight without finish plate mounted.  The next step was to sand the paint down to bare fiberglass just below the portlight and halfway up the sides.  The width of the finish plate that overlaps the port itself - the portion that would rest on the cabin wall surface when mounted - is about 1/2".  This 1/2" width across the bottom of the portlight rough opening, and halfway up the sides, is what was sanded.  

With the sanding complete, it was time to solvent wash the sanding dust and begin to tape the surfaces to protect against epoxy adhesion.  The cabin wall surface around what was to be worked with epoxy was taped and protected.  The portlight itself was taped - the portions that protruded through to the interior of the cabin space; and the finish plate was protected with tape as well.  Here is a picture showing all surfaces protected with tape and reinstallation of the portlight.  Ready for epoxy.

...here is a shot of the void just below the finish plate that was to be filled with thickened epoxy.

     The final product:  West System epoxy thickened with a mixture of 407 low-density filler and 406 colloidal silica forced into the void between the finish plate and the cabin wall, around the bottom half of the portlight.  Later, I will remove the portlights, clean, and bed them in polysulfide to complete the installation. 

Portlights Installation

     With the third coat of finish paint on the coach roof, it was time to begin the installation of the new portlights.  Froonie's original non-opening portlights had simply fallen into a state of disrepair - some 43 years of life had taken its toll on the aluminum frames and acrylic glass.  The frames were powdered and generally disintegrating around the fastener holes, the gaskets were extremely dry and brittle, and the glass was...well, less than transparent.  I found a pair of non-opening portlights at a local marine chandlery that had some age to them, but had never been installed.  I had the original non-opening portlights with me while inspecting the new ones, and found that I would have to make some modification to the rough opening.  I would also have to drill and tap for new fasteners - which as I write this has been completed.  In the end, the price was far too good to pass up, so I made the purchase.

     My first first order of business was to create a template of the inside frame dimension - the portion of the portlight that would define the rough opening.  I do not have a picture to illustrate in this post, but will provide a better visual explanation in upcoming posts.  With the template created, I centered it over the existing smaller opening created for the original non-opening portlights.  I traced the template onto the cabin side to prepare for cut out.

     Using my cordless Ryobi spiral saw, I opened up the rough opening to accommodate the new, larger non-opening portlights.  What appears to be a box on the interior is in fact a box - I taped an empty box over the rough opening to catch the fine dust and fiberglass shards created by use of the spiral saw.  With 90% of the interior completed, I was attempting to prevent more clean-up - the box worked perfectly.

...and the dry-fit.

     Due to the slight convex curve of the cabin sides, and wanting to prevent water intrusion through large gaps in which the polysulfide may fail, I decided to fill the larger fore and aft voids with thickened epoxy.  I removed the new ports from their newly fitted rough openings, and roughed-up the interior of the outer flange.  Roughing the surface of the flange would provide for the best mechanical bond surface for the epoxy.  I then taped the cabin sides under and surrounding the portions of the flange to be worked with epoxy - protecting the cabin surface and preventing the epoxy from bonding to it.  Next, I wiped down the sanding residue from the port flanges and then began to mix epoxy.  I used West System epoxy with 407 Low-Density filler and 406 Colloidal Silica as the thickening agents.  After the epoxy was ready to use, I reinstalled the ports, taping in place to hold firmly in position as the epoxy kicked.  Once the ports were in position, I used a tongue depressor to push and pack the thickened mixture in and under the flanges, and created a smooth fillet.

     After the epoxy had kicked and fully cured, I removed the ports and cleaned the surrounding surfaces of the cabin sides.  I then sanded the epoxy fillets to prepare for final installation and bedding in polysulfide.  Results below...again, a dry-fit.  (yes, that is non-skid applied)