# Resealing and rebedding cabin windows/ports with Butyl tape



## WildJasmine (Sep 10, 2011)

I used 3m marine silicone sealant to seal the first window I redid and it worked alright. After seeing how fragile the silicone is once its cured I was worried that one big wave or flex in the hull would break the seal.

So I figured I would try it out with butyl tape on the next one and here is how it went.

The first step is to remove the screws from the inside cover.










Unfortunately, half of the screws were stuck and would not come out. In the process of trying everything to remove them I completely stripped them out. Good thing I have a dremel. I cut a new head into the screw so that a flathead screwdriver would remove them










The cover then just pops off










With the pressure off of the window frame it will be easier to get a putty knife in between it and the cabin top. Cut the sealant around the frame and carefully wiggle the frame away from the cabin but be careful the p26 has tempered glass windows and they will break!




























I then scraped any silicone, gunk and paint off of the cabin sides.










The old seal was pretty gross. These windows were leaking in hard rains so it was time for replacing.



















Once the frame is removed from the cabin the glass can be removed from the frame. To do this there are four screws holding the two piece frame together.



















Remove those screws and the window comes apart.










The inside of the frame is gross!










After that I removed the old seal










Then I cleaned the glass and it was gross!










Once the frame and glass are clean, they can be reinstalled. I am using Butyl tape, which I definitely recommend over silicone. Super easy to work with. I cleaned all of the surfaces with acetone before placing the butyl tape on them.










Once its wrapped around I squeezed it to fit around the window










When the butyl tape is wrapped and formed to the glass I removed the wax paper from the butyl tape and placed it into the frame.



















The butyl squeezes out once the frame is squeezed together and after I screwed the frame back together, a razor blade easily cleans the butyl up.



















I wrapped the butyl around the frame, both on the outer flange and the inner frame that rests against the cabin top.










I wrapped the tape onto the cabin top.










Squeeze the tape around the opening










Slide the window in and Screw the inside piece of the window back in!










Once the window is screwed in cut away the excess tape.

All done!

Its been a couple weeks now and the windows do not leak a drop. I will now seal everything I can find with this stuff. Its great!


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## sea_hunter (Jul 26, 2000)

I prefer SikaFlex, sandable, paintable and even good under water. East to remove if/when required.


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## WildJasmine (Sep 10, 2011)

I'm sure sikaflex works great but Im not a fan because its still a curing sealant. They are messy to work with, once the seal is broken it has to be redone, and its expensive.

I bought the butyl for $5 a roll and it did all of my windows. $5. It is non toxic and super easy to work with because it has the consistency of ABC (already been chewed) gum. The thing I like about it the most is that if the seal breaks for some reason, it reseals itself the next time it heats up.


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## Ajax_MD (Nov 24, 2009)

I agree. Great job!


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## rackham the red (Jun 24, 2012)

Thank you for providing this information. I really need to do this to two windows in my boat.

I have built several HDPE lined pits and used black butyl tape for the liner, which last 15 years without leaks. I never considered using it for the windows.

I am ordering my supply of white or grey butyl tape. 

Thanks Rochelle


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## WildJasmine (Sep 10, 2011)

Just realized I posted this in general discussion, maybe it belongs more in the gear and maintenance forum? That is where I meant for it to be. Oops 

Feel free to move it


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## cb32863 (Oct 5, 2009)

Nice job and perfect timing as I am going to be doing this with all of my ports after the end of the season.


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## azguy (Jul 17, 2012)

Looks great and it appears easy enough to do, thanks for the tip


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## jrd22 (Nov 14, 2000)

I'm not sure how well the butyl is going to adhere to the smooth glass, especially in cold weather. If it bonds well in all temps then that is an easy way to reseal ports. I used Dow Corning 795 which is an industrial glazing adhesive. Faster (mod here on SN) recommended it and it's an excellent product. As big a job as it is I wouldn't want to experiment.


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## chrisncate (Jan 29, 2010)

Don't think of butyl as bonding like an adhesive, it doesn't. Think of it as a rubbery type substance that never hardens and seals only by the pressure of being bolted between components.

It _can_ break it's seal if not sandwiched under consistent pressure of a through bolted/sandwiched between two items application. It doesn't shrink in cold.. it just gets stiff. If it does develop a leak in cold, a heat gun and a very slight tightening of the fasteners will remedy the situation unless too little for the application was used or too much was squeezed out during the initial install and tightening of the fasteners.

With butyl, even when you have a repair/small leak issue - it's so easy to remedy and fix/work with, there really is no comparison to goops that cure and age.


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## jrd22 (Nov 14, 2000)

Understood Chris, I use butyl for all my deck hardware but making a water tight seal on glass is extremely difficult, especially since the different materials expand and contract at different rates. I'm just saying that between the frame and the glazing there isn't generally a great deal of compressive force and I'm not sure using butyl is the best material for this application. I may be wrong, maybe Mainesail, who got us all started using butyl, will chime in here with his experience. Re-sealing ports is a time consuming job, not something you want to have to do more than once.


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## chrisncate (Jan 29, 2010)

Good point, mine were all through bolted and I could adjust/apply pressure fairly precisely - not all (not most prolly) ports are like that. Still though, it'd be a tough call as even when butyl does develop a leak, it's so much easier to repair. Any curing goops would necessitate a total removal of all the old material, new surface prep and a full re install whereas butyl can be fudged with with a heat gun and some manipulation right in the trouble spot.

I don't know what would actually be best for a light pressure application like some ports would apparently be. Tough call I guess.

Mine (well, some other guys now..)


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## WildJasmine (Sep 10, 2011)

jrd22 said:


> Understood Chris, I use butyl for all my deck hardware but making a water tight seal on glass is extremely difficult, especially since the different materials expand and contract at different rates. I'm just saying that between the frame and the glazing there isn't generally a great deal of compressive force and I'm not sure using butyl is the best material for this application. I may be wrong, maybe Mainesail, who got us all started using butyl, will chime in here with his experience. Re-sealing ports is a time consuming job, not something you want to have to do more than once.


Butyl is used by many auto manufacturers to seal windshields. It is laid down, the windshield is placed on top then a secondary seal typically made of rubber and metal is fastened into place using mechanical fasteners or adhesives.

Butyl seals glass with no issues as long as there is pressure applied which is why I used it. When I originally looked into using it I contacted a glass shop who told me that they use it to bed glass into aluminum window frames. my frames are aluminum. Trust me when it was not easy to squeeze those 2 pieces of frame together and the pressure is held by the four screws holding the frame together.

Hopefully this addresses your concern.


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## Maine Sail (Jan 6, 2003)

jrd22 said:


> Understood Chris, *I use butyl for all my deck hardware but making a water tight seal on glass is extremely difficult,* especially since the different materials expand and contract at different rates. I'm just saying that between the frame and the glazing there isn't generally a great deal of compressive force and I'm not sure using butyl is the best material for this application. I may be wrong, maybe Mainesail, who got us all started using butyl, will chime in here with his experience. Re-sealing ports is a time consuming job, not something you want to have to do more than once.


Only in recent years has the auto industry moved away from installing windshields with butyl ribbon tape. It worked for 50+ years on car glass bumping up and down the roads of the world....


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## jrd22 (Nov 14, 2000)

Butyl it is from now on for all ports and windows!


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