RIck:
I replaced the side cabin windows a few years ago.....I used Sikaflex
295UV and the primer. My windows have no frames, no screws,
fasteners....they are flush with the side of the cabin. The Sika is not
expensive, it's the primer that is expensive but I wouldn't use it
without the primer.
I thought about using Plexus, however, Plexus was what I took out of the
old windows. It had hardened like a resin and separated from the
gelcoat which was the cause of my leaks. The Sikaflex is holding up
quite nicely....it is still quite soft and pliable and none of the
windows have separated from the gelcoat.
I had my car windshield replaced last year.....they used a Sikaflex.
product .....one main difference is that it has a shorter cure time.
If my cabin windows had a frame(s) and screws/fastners, I'd use butyl
over Sika any day.
Last year, I replaced the gaskets in my hatches....for that I used a
black silicone product.
Different jobs, different adhesives.
Bob Abbott
AZURA
C&C 32 - 84
Halifax, N.S.
On 2013/02/09 12:25 PM, Rick Brass wrote:
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, 2^nd 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] <mailto:[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] <mailto:[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
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