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  #1  
Old 12-15-2007
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Which silicone for portlight glass?

Which should I use for sealing the glass into the frame - under the bezel etc.

Thanks for any knowledgeable input
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Old 12-16-2007
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I hope some of the knowledgeable people answer this because I have the same problem and have all kinds of conflicting advise.
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Old 12-16-2007
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I used Boatlife Life Seal. Works like a charm. You have to be careful what you use, as some products (like Boatlife Life Caulk) are not compatible with plexiglass or lexan.

http://www.boatlife.com/productsdeta...rdID=57&cat=CS
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Old 12-16-2007
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Yes, some beddings and sealants (not the same thing in some fittings and situations) will eat the "glass". If it is REAL glass, you're OK to use silicone, like in a house, but is it real glass?

Also, you can get away with stuff on Lake Ontario, for instance, that I wouldn't recommend at sea. My new, intended for the ocean boat has a thick strip of bedding and about 30 thru-bolts per 1/2" thick pane of Lexan.

My old C&C has acrylic panes I cut myself (1/4" thick), bedded in a silicone bead, and gasketed with the original rubber "squish and snap" stripping. Different boat, different materials, different technique. (Neither set-up drips, however, even in a driving rain.)
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Old 12-16-2007
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GBurton,

Good advice here to check compatibility of the silicon with the lens material. However, there are may also be issues of incompatibility with silicon bronze portlights. You should not use an acidic silicon with such portlights, as it will cause surface corrosion. I believe it is BoatLife that offers a non-acidic silicon, but double check that.

Are these the Whitewater Marine bronze portlights? If so, I have some additional suggestions....
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Old 12-16-2007
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C&C used Sikaflex (?sp). DON"T use 5200. When I replaced the plastic windows,the yard used 5200 and the windows fell off in 3 weeks and they had to grind the 5200 off to re-replace the windows.
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John - not sure of the brand. There are no manufacturers marks on the portlights. Here is a picture....

http://www.johndanicic.com/screens/s...-PSC%20Nok.htm
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Quote:
Originally Posted by GBurton View Post
John - not sure of the brand. There are no manufacturers marks on the portlights. Here is a picture....

http://www.johndanicic.com/screens/s...-PSC%20Nok.htm
GBurton,

Yes those are the Whitewater Marine SB portlights. They are nice portlights, but they have some design shortcomings. If you have them all taken apart right now, please send me a PM and I will give you some tips on what you can do to make them more reliable/weatherproof. I rebuilt eight of them a few years back.
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Old 12-16-2007
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Quote:
Originally Posted by JohnRPollard View Post
GBurton,

Yes those are the Whitewater Marine SB portlights. They are nice portlights, but they have some design shortcomings. If you have them all taken apart right now, please send me a PM and I will give you some tips on what you can do to make them more reliable/weatherproof. I rebuilt eight of them a few years back.
John, could you do me a favor and copy me on that PM. I have the same ports on my older vintage PSC and would like to keep this info on hand for the next time I do maint. on them. Thanks.
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I suggested PM because didn't want to bog down this thread with details, but at your request here's some info about the Whitewater Marine portlights:

The Whitewater Marine silicone bronze portlights were used on quite a few traditional style boats in the US/Canada during the '70s and '80s. You see them on Westsails, Cape Dories, Pacific Seacraft and their ilk. The most common version is oval in shape (available in different sizes), although you sometimes see round versions. They are nice, solid portlights, through-bolted to the coachroof for safety, and aesthetically pleasing. But they are not without shortcomings. Because of these shortcomings, Pacific Seacraft switched in the late 80's to a newer rectangular style silicone bronze portlight of their own design.

The problem with the Whitewater portlights is that due to their design in time they will leak and the lenses will become hazey if not properly maintained. Another problem is that brass machine screws were used to hold the bronze portlight flange in the bronze sash. These brass screws cease-up, sometimes crumble, and are difficult to deal with when trying to re-build the portlights.

So I was going to recommend that GBurton back the brass screws out of the sash now and coat them with loctite before he exposes the portlights to saltwater (GBurton has a virgin Westsail 32 that he found and is preparing for sea). I would also recommend that he swap out the laminated "Safety Glass" lenses for either acrylic or lexan. The "safety" glass lenses can shatter (ask me how I know), and wicking of moisture between the laminated glass layers is what causes them to become hazey/cloudy.

Below are two posts that I previously made to Sailnet's Pacific Seacraft e-mail list-serve in which I discussed the rebuilding of eight Whitewater Marine portlights on our previous boat, a PSC Dana 24. Our current boat, a PSC Crealock 31, has the designed-by-PSC rectangular portlights which are a superior design in every respect (but, in my opinion, not as aesthetically pleasing as the oval WWM portlights.) The reason I consider the PSC design superior is that it relies on one and the same gasket to seal the portlight sash to the portlight frame AND to seal the lens into the sash (the PSC portlights also incorporated a self-draining feature to shed water off the portlight frame exterior). The Whitewater portlights took a different approach, as described below:


____________________________________________


JohnRPollard: "When I rebuilt the portlights on our Dana, I ended up using acrylic rather than polycarbonate (Lexan) or glass. Though somewhat stronger, polycarbonate is more sensitive to UV than acrylic. I did not want to go back to glass after having one of the large ovals shatter on me (when it unclipped from the overhead and swung shut). Acrylic is plenty strong enough for the size of these portlight openings. [I bedded the new lenses with non-acidic silicone.]

The original oval portlights were manufactured by Whitewater Marine in Florida and last I checked replacement gaskets were still available from them. While I prefer them aesthetically, the design of the oval portlights was inferior in that it relied on a mastik like bedding to waterproof seal the glass lens into the sash of the portlight, which was then held in place by a flange that was screwed into the sash. Of course, over time the mastik bedding would fail, allowing water to get in behind the flange and eventually wicking between the laminated layers of glass. This is what causes the cloudiness. The same water also got into the threads of the brass machine screws that held the flange in place, causing them to seize up and eventually crumble when removal was attempted.

All of this was separate from the issue of leaky gaskets, which have much less to do with the cloudy glass. [The gaskets are used to seal the portlight sash against the portlight frame. The gaskets do not provide a seal around the lense -- that is sealed with the mastick-like bedding.] [Inspect the gaskets and replace them if they're beginning to get too hard and cracked.] If your [portlight sash is leaking where it contacts the frame] and the gaskets appear to be in good shape, there is a set screw in the portlight hinge that must be adjusted from time to time so that the sash seats flat against the portlight frame upon closure. If you replace the gaskets you'll also have to reset the set screw (with a very small allen wrench).

The newer rectangular bronze portlights use one and the same gasket to both seal the portight upon closure and to seal the glass frames. It's a simpler, better design."


JohnRPollard: "Dave makes good suggestions below about drilling and re-tapping. When I rebuilt the oval portlights on our former '86 Dana, I had maybe half a dozen or so of the little machine screws that crumbled on extraction and had to be drilled out and re-tapped. I had never done that before, but by going slowly I achieved good results. I also learned to liberally soak (usually overnight) the old machine screws in penetrating oil before attempting to remove them, which greatly reduced the number of "failed" extractions.

One of the shortcomings of the oval portlight design was that they used brass machine screws to hold the bronze inner flange in place. So as the bedding fails and water begins to penetrate, the machine screws eventually turn to powder (brass sacrifices to bronze ?). I think that is why so many of them crumble on extraction. I expect you tackled the most leaky of your portlights first, which would account for the high rate of failed machine screws. As you move on to less leaky portlights, you will find more of the machine screws intact and extractable. And that is good incentive to get going on the project before they get any worse. [The other problem with the oval portlight design is that, when the bedding around the lens begins to fail, water begins to wick up between the two layers of laminated safety glass, causing the often seen cloudy film around the perimeter of the lense.]

I was not able to find bronze machine screws in the right size. I ended up using brass again, but carefully insulated them with Loc-tite. I also generously re-bedded the portlight lenses and flange in non-acidic clear silicone. I was not able to find a ready source of the mastic-like substance that was originally used (similar to what is used to bed automobile
windshields).

I polished ours up using the polishing kit that is available for my
Black and Decker "Mouse" sander. The looked like gold when I was finished.

I don't know where your re-built portlight is leaking from, but after replacing the gasket, you must carefully adjust the set screw that is in the portlight hinge so that the portlight sash closes evenly onto the frame. If you don't do this, no matter how hard you try to snug the wing nuts, they will leak like a sieve."
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