Rebedding Taiwanese Trawler windshield

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DHeckrotte

Guru
Joined
Nov 1, 2015
Messages
1,024
Location
USA
Vessel Name
Revel
Vessel Make
1984 Fu Hwa 39
I have removed the windshield from in front of the helm and had a new one made. The old laminated safety glass was delaminated and fogged. The sealant appears to have been polysulfide. Where it was intact it was utterly tenacious; where it was not, it wasn't and leaked.

The system / design is pretty poor. Any leak under the exterior trim admits water to the wood framing; it is not 'self flashing' like any decent design and decent house window would be. It would have been far better if the fiberglass exterior had been dished inwards and the glass sealed into the dish.

Happily, the interior trim is Teak, as well as the exterior. Interior damage is therefore limited to the Teak-veneered plywood and perhaps to the structure behind. The house sides appear to be a cored structure, but it's hard to verify.

Trim pieces were glued at the corners so that the thinner exterior pieces will stay in plane as the screws are tightened on soft sealant. The assembly depends upon those glued joints to be waterproof. I therefore have glued the corners again. An unattractive alternative (for varnished trim) would have been to have opened the joint space a bit and used sealant.

The window glass was bedded on polysulfide but the interior bedding has nothing whatever to do with being waterproof; leaks would simply dribble down between the interior trim and the inside of the hull 'glass. I will bed the new glass on the interior trim using butyl tape; thus there will be no mess that squeezing uncured sealant would make where I could not reach to clean.

I will bed the exterior trim in polysulfide, taking care to fill between the window frame and the fiberglass surround. Interestingly, the only readily available polysulfide is BoatLIFE-Caulk. (Their Lifeseal is a polyurethane-silicone.) Their instructions tell you to use their special primer on oily wood like Teak but essentially no one stocks this expensive elixir. I bought it and will use it.

Pics include one of the lower right (inboard) corner of the windshield. Note that the cutout in the 'glass has only about 1/16" cover by the exterior trim. I cleaned the edge of the fiberglass and gooped it full of filled epoxy; I will end up with at least 1/2" of sealant.
 

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BoatLIFE-Caulk is a good product. I had a yard and it was my primary caulk. I bought it by the case and had excellent results. Now as a private boat owner without the need for a case, sellers have the price so jacked up that the product sits on their shelf for months or years and is so thick, almost unusable.
 
Moisture gets in the edges of safety glass thru most bedding compounds.

Sealing the edge with epoxy or even just varnish may get a few more years out of the new glass.
 
looks pretty much like mine on a 83 43' ocean alexander.

The hull sides are cored with full 1/2" plywood, then strips of 1/2" plywood to act as furring strips and a base to nail the 1/4" plywood substrate to (nailed with ring shank nails), and a final 1/8" teak veneered layer of plywood glued to the 1/4" substrate with contact cement.

I am in the middle of replacing all the windows with new laminates because the old ones had bubbling of the tint around the edges of the glass. So far it has cost $160 a window regardless of the size. I have 17 windows plus 3 thick windshield panes. The cost driver is the solar tint I am using, so says the glass shop. Although the flex track and felt edge pieces arent cheap either. *sigh*

Gorrilla super glue gel has worked exceptionally well for gluing the frames and trim back together when broken. you only have to hold it for 10 seconds thankfully. Another great glue for teak is has been loctites 5 minute clear epoxy (home depot).

I plan to bed with this stuff...
http://www.pksupplies.com/crl-777-butyl-rubber-sealant-11-fluid-ounce-cartridge.html


here's a pic of the plywood lay up...
11128-albums589-picture3716.jpg
 
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Barnacles, I fear you'll learn to utterly HATE the butyl sealant. My personal experience with it was in sealing slip joints in copper flashing. It worked perfectly for a good many years before I sold that house. The problems I had were two: it's even more pervasive, stretchy, stringy, droopy and messy than 3M 5200 and it NEVER dries. My copper flashing design had a nearly concealed joint so it did not present an ongoing annoyance. I've also come across it in concealed locations within commercial aluminum doors; I had trash picked 'em on a jobsite, took 'em apart and made the size doors I needed; they were at least 40 years old and the butyl sealant was still gummy and stretchy, doing its job.

The description on your website says that it's for concealed locations. There may be other formulations which would behave more like normal sealants.
 
thanks for the heads up. maybe I need to buy a single tube and test bed something before putting in a bunch of windows.
 
In my experience with tinting windows the hassle is the tint absorbs the energy , so the window glass gets hot .

We created sun screens that have identical mounting , inside or out.

For a bit of privacy they can be snapped up inside as needed.

For heat control there installed out side to keep the heat outside.
 
I used Sikaflex (292?) when I rebidded my windows 10 years ago. Still making a good seal.
 
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