Bedding Window Frames with Butyl Tape and Sealant

[Vincentc]

I reworked and rebedded the port side cabin windows with boatlife polysulfide sealant shortly after we got the boat and within no time I had small leaks between the aluminum frame and the cabin side.

Once the rain stopped after TS Lee I removed the windows, old caulk and set out to remove and epoxy the rotten coring on the stb side windows, which I did not get to last time. A PO had apparently bedded the stb window frames with silicone caulk/sealant but did nothing for the coring.

I struggled with the quandray of sealant choices and searched the forum and other internet sites. My review of process recommended by Sams for glazing the fixed windows got me thinking about adapting its use of buty tape to my project. I also found this site and comments on Butyl tape interesting:
http://www.pbase.com/mainecruising/rebedding_hardware

I decided to use butyl tape to bed the aluminum window frames coupled with sealant out of the caulking gun. The tape does not easily compress and should allow a thick and consistent bead of sealant around the outer edge of the frame.

I am also going to bed the stainless screw heads with butyl to seal them and insulate the aluminum from the stainless.

I purchased some 1/8 x 3/8" butyl tape from a glass company and am running the tape around the perimeter of the window frame leaving a 1/4" gap from the outside edge. After applying the buty tape to the aluminum frame I ran a thick bead of 3M 4200 around the outside perimeter of the port window frame. I plan on using RTV Silicone on the stb side since silicone was previously applied there. I was impressed with how well the silicone still stuck to the aluminum and fg.

I installed one port frame last night and hope to get the rest rebedded tonight.

I'll let you know how it works and may remember to take some pictures tonight.

While I am working on the windows, my son is painting the bottom of the Oday without a haulout. I did get a picture of that.




Regards,
Vincent

[sgharford]

Thank You for sharing - very interesting link you posted about butyl tape. My 1971 30' Bristol sailboat I sold my brother had thru deck fittings with butyl (assume original) that is still holding up very well. Looking forward to pictures and what others have to say about it. I'm coming out early (this weekend) to replace rotten deck core on port bow and repair and re-bed all my salon window frames. Gonna follow your lead on this one.

[rsmith]

I had a 10,000' metal building built about 20 years ago. They used the butyl tape all over the building including the roof panel seams. never had a leak in the areas where they used the butyl. I ended up with the typical box of extra stuff and had boxes of the butyl tape. I used it for years for all kinds of things but never thouht about using it as a beding compound untill I went to SAMS and got the materials to rebed my front windows. I fish the boat hard and and have been breaking windows since I stepped on the boat 35 years ago. I've tried all kinds of caulk and bedding ideas over the years but the butyl is working the best. I've never been able to tell if the broken windows is from the flexing or movement in the frame but the ones I did with the SAMS method are good after 6 years. I dont know how efective it is but when I buy the window glass I pay the extra to have the edges polished to relieve the stress points from cutting.
I've thought about glassing in the front windows but when we are just hanging out in the Bahamas its nice to open things up and see whats going on around you. I've never understood people who get on a boat and close all the curtains.

[Vincentc]

At this point I've rebedded 4 cabin window frames and can share the following:

Removing is a challenge. The frames were too tight against the cabin for the multitool blade. I used 2 wood chisels and a rubber hammer. I started at one corner and gradually worked my way around the frame. You have to be careful not to bend the frame.

Creating mounting studs by putting a couple of long screws in the top row of screw holes near the corners and cutting off the heads with a metal cutting angle grinder blade is a big help, and will also put a lot of tears in your pants.



Masking tape on the cabin around the perimeter of the frame allows you put in sealant without a lot of clean up. The day after the install when the sealant is cured but still green, I ran a blade around the window frame then removed the tape leaving a pretty neat look. Suction cup handles are a big help handling the glass. The studs hold the frame in place and the butyl tape holds the frame out from the cabin side leaving space for the sealant caulk.



I can then run a bead of 4200 around the top and side of the windows, then snug it up with screws wrapped in butyl tape. When the screws are tightend up the buty squeezes out around the screw head. The photos shows the butyl excess which is easily pinched off. One of the alignment studs is also visible. A pair of vice grips allowed removal of the studs.



This is how I wrapped the screws with butyl.
Please excuse the phillips heads. I did not have square drive in the length I wanted. The old screws and holes did not hold well when I cranked down on them with the cordless drill driver. I drilled out the holes, all the way through then squirted in some West Six-10 filling the holes and after that cured, drilled the pilot holes. (Six-10 is a great tool. It allows you to shoot premixed thickened epoxy gel into holes with ease.) #8 x 1 1/4" screws are a bit longer than the OEM and worked fine.



Regards,
Vincent

[Vincentc]

More photos and Comments. You are only allowed 4 photos per post.

The frames had some significant corrosion. I wonder if the silicone sealant used when they were last rebedded, added to the corrosion. The stb side frames were more corroded than the port side. I used a wire wheel on a drill to remove the corrosion. The frames were also sanded, wiped with a caulk remover, then MEK and then denatured alcohol. I discoved and used this latex primer for aluminum at Lowes.



Here is the stb fwd window with 2 rows of 3/8" x 1/8" butyl tape. On earlier window rebeding I used only one line of butyl tape and applied the 4200 in a thicker bead to the frame before setting it in place. On this window I applied the sealant after mounting the window and before screwing it snug against the cabin side. This way avoids the mess of handling the frame with wet sealant but does not allow you to apply sealant to the bottom side of the frame, since there is not room for a caulk gun there.





Regards,
Vincent

[eze2bme]

Great thread ... thanks for the photos!

[MikeP]

Good info/nice pics. I discovered the hard way (as you have) a while back that Boatlife caulk is useless and, IMO, should not be carried/used on a boat. It failed (leaked and/or cracked) in every application I used it for. I use one of the 3M products depending on what I'm doing.

[Angela]

Thank you, Vincent. There are a few threads like these that I file away under the "Hatteras Gods" folder and this will be one of them. The fact that you added a lot of very helpful photos helped me to completely understand what you were talking about, and I didn't have to try to use my imagination so much to comprehend it. I am anxious to do the windows in my raised cabin section on the bow, both of which do leak, this winter and I feel a lot less scared of the job now because I have a much better understanding of how to do it and what to expect. Thank you.

By the way, where did you find those glass grabber handles? I can't find them any any of the Home Depot type places.

[Vincentc]

Your are welcome.

The suction handles came from Amazon.com.

Regards,
Vincent

[Canuck Dennis]

Ace Hardware had them in Cape Coral.