Help - Infamous Leaking Taiwanese Windows

I know. The "Decks & Cabin Top replaced and re-fiberglassed, & Entire Boat Painted (04/05)". I think that is when they did the windows.

Live and learn

The first 6 Windows took days to remove as I was trying to save the teak and just replace the broken glass and seal the leaks. Now I know that was a waste of time and two multi tools on black goo.

This time I used a circular saw and cut the entire window out. I cut thru the frames to keep the original size hole. If you are ok with a 3/4 in larger window, run the saw around the frame. Then you won't have a 1/2 in of trim to remove. Removed the 4 salon windows in 2 days. After the new ones come a day to install with sikaflex. Pics to follow unless I can figure how to upload from my phone.

I just posted photos of a number of projects on DIRT FREE on my website including replacement of 17 leaky wood frame windows with Custom Bomon aluminum frame units

Ray another thing to look at is the wood "drip rail" around the top of the aft cabin. Rain water comes off the flybridge roof and drips on the aft cabin roof and also directly on this rail. If you watch this in a heavy downpour the water will run down the drip edge and try to find a way in at screw holes and un-caulked gaps. It also will curl around the drip edge and wick itself in on the bottomside of the edge. dont ask me how I know good luck, Bruce

I'm a newbie just today...hope I'm doing this right.


What is the consensus on bedding material for glass against plywood that is held in place by exterior trim screwed to the ply? Seems the choices are butyl rubbers, polysulfides, and polyurethanes. What will stick to both wood and glass and provide a seal?

I supplied an answer in your first thread. Might want to keep just one thread going at a time to keep all answers in one place.

I guess polyether is another option (West Marine Multicaulk)

I think the prejudice against silicone is a tad overstated. It has its place. I had a very leaky skylight with two panes of glass on this boat when I got it. Took both panes out, put two new panes in with silicone. No leaks and looks great. I also went around to all my outside windows and using a tool dragged out a lot of old non silicone caulk that was all dried out and pulled away and leaking. Cleaned it all out and then put a nice bead into the fresh gap and left it a bit proud and now watch it shed water nicely and no more water in the house from leaky windows. Is it the best? No. Is it OK for occasional use and putting off bigger jobs till later? Sure. Its also a lot easier to get stuff apart with sili than if one uses Sika or 5200.

Ok, sicilicone prejudice! Guilty! My PO used it. Everywhere outside he used it the white turned black. Have had to sand and grind it off. Replaced with 3M 4300 and no problems. Paint will not even stick to the stuff. I wish you better luck than I had with it. Worked great in the galley and shower however.

I will continue to pay a little more for 3M.

Hi folks, Here is a product that works well for those leaking windows
CAPTAIN TOLLEY'S Crack Cure Sealant, 2 OZ. | West Marine

I have unlimited success with this product to the extent that I have not completely used a bottle up as other persons require it and the bottle is offered never to return!!
Just continue to trace your window frames till the fluid will not be absorbed per instructions.
Neat stuff well worth the purchase.

Al-Ketchikan

I used the Marine grade clear stuff, works fine.

Since there were more pressing issues with my MT, I decided to use good ole Lowes calk temporarily until I can get to re-bedding the windows.Haven't had an issue since.

On my 77 m/t sedan the inside teak trim is held in place with screws from the outside, the windows were the placed on the raw plywood with the one half sealed in with 5200 the back half was place in sliders like those used in car side windows. then the outside teak was attached with screws and bungs and 5200.
When I purchased the boat it was 9 years old and they all leaked. I removed the bugs and very carefully pried out on the teak molding while cutting the 5200 with a steak knife. I only broke one piece of the molding which I glued back together. The teak is very brittle so be careful.
With the window out I cleaned, filled & replaced the plywood as needed I then fiber glassed the opening all around, I also added extra drain holes and made them larger. The problem is during a driving rain more water will hit the window and run down into the gap faster than the drain holes can handle it, so the excess water will go under the sliding glass to the inside of the boat especially if the wind is driving it.
When we have a hurricane I seal them with duct tape. Another thing, Put a padded mattress cover like they use in motels that keeps water from going into the mattress, this will keep the underside of the mattress dry. The moisture from our bodies will go right thru and condense on the cool plywood causing mold.

78puget-trawler said:

I think the prejudice against silicone is a tad overstated. It has its place. I had a very leaky skylight with two panes of glass on this boat when I got it. Took both panes out, put two new panes in with silicone. No leaks and looks great. I also went around to all my outside windows and using a tool dragged out a lot of old non silicone caulk that was all dried out and pulled away and leaking. Cleaned it all out and then put a nice bead into the fresh gap and left it a bit proud and now watch it shed water nicely and no more water in the house from leaky windows. Is it the best? No. Is it OK for occasional use and putting off bigger jobs till later? Sure. Its also a lot easier to get stuff apart with sili than if one uses Sika or 5200.

Click to expand...

The trouble with silicone is that it is clear, so is very attractive to use in a variety of applications. Lowes sells a much better product that is also clear called Lexel. I have used Lexel successfully in a variety of outdoor applications. I will not buy silicone again. The PO of my boat used silicone extensively and I spent the first few years trying to get rid of it. I haven't seen any for quite a while now, and leaks have stopped. That is no coincidence, as the silicone was responsible for many leaks. It adheres well for the first day or so, then it lets go, but since both the silicone and the water are the same colour, the leaks are difficult to trace. Pulling the silicone out is the only way.
I don't see this as a prejudice, it is just the way silicone is. It was never designed for outdoor use.

Silicone Rubber Sealant Cartridges - BoatLIFE


This stuff is.

koliver said:

Lowes sells a much better product that is also clear called Lexel. I have used Lexel successfully in a variety of outdoor applications.

Click to expand...

That Lexel looks like pretty good stuff as long as you realize it "Will not adhere to or is incompatible with Aquaseal®, Kynar®, polypropylene, polystyrene foam insulation, polyethylene, rubber, silicone, Styrofoam® (it dissolves it), Teflon®, vulcanized rubber, and waxes" per the company website.

I have sealed up hard to stop leaking glass windows in mahogany frames and lexan in wood hatch using Loctite PL S30 which is a black polyurethane soft rubber.

Loctite PL S30 10 fl. oz. Black Polyurethane Roof and Flashing Sealant-1675273 - The Home Depot
And it is cheap cost.

http://www.loctiteproducts.com/p/pl...-S30-Polyurethane-Roof-&-Flashing-Sealant.htm

The lexan hatch would always break its seal and leak after a few months, but with this Loctite S30, going on now 2 years and still is perfect.

All my windows, except for them that slide open, and that hatch simply sit in a rabbeted wood frame.
The S30 is plenty strong and tough. I smooth the bead with my finger.
After a cure, I then paint over the black S30. I tape a line on the window glass to match the inner wood frame. And the paint gives it a clean line on the glass.

Another caulk is Sika Flex Pro available at the big box stores at a great price because it's not labeled marine.

I've used the Lexel in places that I wanted clear sealant and the ability to varnish over. I've been pleasantly surprised that it actually works and seems to have lasted. One of the positives I hope for is that I can get the parts back apart that I bedded in Lexel.

Pics are of winch mounts that I made in 2012 for the LeComte 38 we're selling. The taller winch mounting is original to the boat and I replaced the Teak mounting blocks with solid fiberglass since there was no way to refinish the Teak while it was in place. I made a Teak cover for the new fiberglass where it showed. The shorter winch mounting is all stainless steel and was installed later. I made solid fiberglass blocks and Teak blocks covering the stainless so that the winch mount would look like the original. Winches were bolted vertically through the deck and horizontally through the Teak coamings. I bedded the fiberglass in 5200 and the Teak parts in Lexel so that no white sealant would show adjacent to stainless. The solid fiberglass is painted with Brightside Polyurethane and the Teak is finished with Cetol.

raindr said:

Ray another thing to look at is the wood "drip rail" around the top of the aft cabin. Rain water comes off the flybridge roof and drips on the aft cabin roof and also directly on this rail. If you watch this in a heavy downpour the water will run down the drip edge and try to find a way in at screw holes and un-caulked gaps. It also will curl around the drip edge and wick itself in on the bottomside of the edge. dont ask me how I know good luck, Bruce

Click to expand...

I found this problem on my MT44. Not only did water enter through the screw holes behind the drip rails the drip rails also created a waterfall on my aft head window and the equivalent window on the port side. I suspect the teak handholds along the salon are also leaking.

My solution was to remove the drip rails. Where the wood inside was still good. I Allowed it to dry out and injected epoxy through the screw holes then used an epoxy filler on the holes. (I'll paint a stripe where the drip rails were when I get to painting) Where the wood was mush, I removed inside paneling and replaced the rotting plywood and then the inside panels before reinstalling the windows. The openings were glassed around the perimeter and the inner frames I epoxied and glassed into the openings. I'm using exterior plywood that is coated with epoxy before being installed.

In all instances my teak frames came right out. In one instance without even removing the screws! The bedding for the frames appeared to be butyl rubber and was totally dried, cracked and crazed under the frames.

The previous owner's solution to the leaks was to smear sealant (silicone?) on the outside frames.

What I observed during a heavy storm is the water ran right over the top of the frame and through the window bedding giving me an unwanted interior waterfall top and bottom of the window.

So if anyone is going the silicone band aid route, be sure and apply it to the glass frame junction too.