I suppose you could take some 80 grit sandpaper to the aluminum frame and the Plexiglas and get Sikaflex to stick, but I'm not sure that would be a great idea.
For starters, Sikaflex is expensive. The Sikaflex tube of Sikaflex and bottle of primer I bought to reseal my foredeck hatch cost somewhere around $150. EPDM seal and spline to reseal an aluminum portlight cost around $7.50 (or $20 if you buy the stuff from South Shore). Sikaflex is time consuming. Sand, prime, cure, 2nd coat of primer, glue, cure, clean up the excess sealer. What? 3-4 hours spread over two days? With gasket and spline you can rebed the Plexiglas is 15 or 20 minutes. Sikaflex seems to suffer bond failures and relatively limited life. There have been a number of comments in discussions about glued in portlights about leaks, poor bonds, and the need to redo the seals after 4 or 5 years. In 1994, someone on one of the precursors to Stu's List advised me that if you never futz with the butyl seal between the aluminum frame and the cabin side the seal will never leak. My 18 years of experience with 2 boats that are over 35 years old seems to bear this out. I resealed the portlights on my 25 when I bought her in 1994, and resealed again in 2006 or 2008 because I replaced the I-don't-know-how-old-and-badly-crazed Plexiglas panels. I replaced the Plexiglas and resealed the portlights on my 38 when I bought her in 2003. I'd guess you can get 10 to 15 years life out of a seal and spline window - as long as the EPDM seal is intact it will never leak. I wonder if the change to glued in portlights really had many benefits. I know they are more stylish and "modern" looking. And I recall that the portlights glued in with Plexus added to the stiffness of the hull structure. But they do seem to require a lot of maintenance. I see that the manufacturers of a number of "traditional" boats like Hinckley, Morris, Aileron, Pacific Seacraft, and IP still use metal framed portlights. While I'm thinking about it, I'm curious about the wisdom of the list on glued in portlights. In the regular discussions about resealing the portlights, Plexus used to be the preferred method of gluing in the windows. There were even listers who owned Plexus gins and would loan them to other listers to do the job. Over the last couple of years, the discussions of glued windows seems to have migrated to Sikaflex or the 3M equivalent that is used in automotive and construction glazing applications. Our boats flex a lot more than cars or buildings, and my engineering experience makes me question the durability of the flexible adhesive bond in our application. Would anyone like to comment on the merits of Sikaflex vs. Plexus for gluing in portlights, and perhaps the reason for the changing recommendation? Rick Brass From: CnC-List [mailto:[email protected]] On Behalf Of dwight veinot Sent: Saturday, February 09, 2013 6:52 AM To: [email protected] Subject: Re: Stus-List Old style aluminum frame portlight gasket Or you could just use Sikaflex 295uv Dwight Veinot C&C 35 MKII, Alianna Head of St. Margaret's Bay, NS _____ From: CnC-List [mailto:[email protected]] On Behalf Of Rick Brass Sent: February 9, 2013 12:38 AM To: [email protected] Subject: Re: Stus-List Old style aluminum frame portlight gasket The D shaped EPDM seal that Dennis recommends makes a much better seal and lasts longer than the foam strip that goes between the frame and the Plexiglas. It also costs a whole lot less than the foam strip if you are buying the foam from Southshore Yachts. Take a small piece of your window spline to any glass shop that repairs storm doors and windows. Window spline is usually what holds the Plexiglas into your storm door. There are several dozen different cross sections for the spline, and the glass shop can determine which is the correct spline by comparing your sample. The last batch I bought was about $.50 per foot for a 30 foot piece. Rick Brass Washington, NC From: CnC-List [mailto:[email protected]] On Behalf Of David Paine Sent: Wednesday, February 06, 2013 10:07 PM To: Dennis C.; [email protected] Subject: Re: Stus-List Old style aluminum frame portlight gasket Sorry to be thick headed but I don't see where this D profile stuff fits in the old style AL frame windows. I have old style aluminum frame windows (CC33 1975) that form a seal with the plexiglass with 1/8" thick and 1/2" wide (I think) double sided sticky neoprene tape which sticks the plexi to the inner flat aluminum extrusion. On the outside there is a hard rubber spline (with a wedge cross-section) that is pressed between the plexi and the outer lip of the Al frame. The frame, of course, is screwed and bedded into the house sides-- so far no leaks there. I'd really like to replace the rubber splines as they have shrunk and grown brittle with age but I haven't seen it available anywhere. Thanks for any insight! David On Wed, Feb 6, 2013 at 9:42 PM, Dennis C. <[email protected]> wrote: Was wandering through WalMart tonight and saw some Duck brand EPDM gasket which I'm pretty sure would work for old style aluminum frame portlights. It's white. It didn't come up on the WalMart site but here's one reference for it: <http://www.myriadgreeyn.com/Bulk-Wholesale-Insulation-Rubber-Weatherstrippi ng-p/cml%201282289.htm> I use M-D Building Products D profile EPDM marine/auto weatherstripping. M-D Product No. 01025. I get it from Lowes. Here's another reference: _____ No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2238 / Virus Database: 2639/5588 - Release Date: 02/07/13
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