Joel,
I found that screws are only screwed into the wood coring under the fiberglass. Remove the SS frame, clean it well with scrapper, and use acetone to remove any residue. Do the same around the window frame and the glass. Then if
the screw holes are just into wood I drilled them out with a 7/8 inch drill (I think). Then I used a router bit in my electric drill to remove more wood, basically under cutting the fiberglass. NOTE, leave 3 or 4 holes intact towards the ends of the window on the top and bottom. These will be used to locate the SS frame when you redrill the screw holes. A turkey baster to blow the residue out of the enlarged holes. Use epoxy to coat the wood in the drilled out holes before using a thickened epoxy to fill the holes. Since the holes are on a vertical surface I used blue masking tape to cover the bottom half of the hole while filling. Then as you add more filler, keep raising the tape to keep the filler in the hole. When it hardens, sand flush and install the SS frame with the 3 or 4 original screw holes. I used a counterbore to mark all the filled holes as it marked the center of the hole. Remove the SS frame and drill new screw holes in the filled holes. Repeat the drilling out, filling and redrilling operation with the 3 or 4 screw holes that were used for locating the SS frame.
I used black butyl purchased in rolls from an automobile window repair shop. I suspect that grey tape has filler and may not seal as well. Place the SS frame in place with a few screws and then mask the outer edges with blue masking tape.Remove the SS frame and wipr the frame, glass and window frame with acetone and keep everything clean until you are finished. Pack the butyl into the voids in the fiberglass/wood window frame. Then install the glass and continue packing the butyl. On my boat the glass was slightly recessed below the fiberglass surface so I added butyl until it was slightly higher than the fiberglass surface. I did not get butyl within about 1/2 inch of the blue masking tape since I used 3M's 4000 around the outside of the windows. Once the butyl is in place, put a big bead of 4000 around the window. Black butyl can easily make a mess of your fiberglass, so I didn't want it near the fiberglass. Also place a circular bead of 4000 round each screw hole. To mount the SS frame carefully hold it away from the glass and install one screw partially at one end of the frame, being careful to keep the frame away from the glass. Then partially install a second screw at the other end of the frame. Now the frame should be suspended about 3/8 ince out from the glass and just barely touching the 4000. Add the remaining screws but don't tighten them until they are all in place, as this will keep the 4000 from squirting out the holes in the SS frame. Then starting at one end tighten the screws. Before fully tightening each screw, stop and unscrew the screw 2 or 3 turns. This will fill the threads with 4000. Finish tightening each screw. Immediately begin wiping the 4000 away from the SS frame and glass. The blue masking tape should keep most of the mess off the fiberglass. Before the 4000 starts to set up remove the blue tape.
It took me two long days to do two windows. I also varnished the interior window frames when the glass was out. The butyl takes awhile to pack, probably about two hours.
Burt Preston
H44 - 83 Exuberant
