Installing true frameless windows anyone?

Hi, I have a 1980 Hatteras37 with aluminum frames which are slowly but surely failing and leaking. I have replaced all of my window seals and followed Hatteras instructions but despite that, and new seals and sealant etc. some of my windows have started leaking again. \

I am musing the idea of removing the frames and window panes and replacing everything with true frameless windows. If I go that route, I would have to:

1. Glass in and fair around the entire opening. I am not sure Hatteras did that before installing the frames.
2. To install frameless windows, I am thinking of using the 3M VHB (Very High Bond) two sided tape along the outside opening
3. Cut the new window panes 1.5" larger than the opening.
4.Attach the window pane by placing over the VHB (I know that placing something over VHB is one attempt, so I would place temporary supports on the bottom side on which I would rest the glass pane and then press it against the VHB.
5. Fill the gap between the glass pane and VHB with good quality caulking. My window tops are recessed under the flybridge structure so only place where I will really need the caulking is on the sides and on the bottom, which is easily accessible.
6. Fabricate teak 'L' shape trim to cover the window opening that will rest against the glass, or perhaps apply a thin sponge insulation tape on the inside of the window pane and then rest the teak trim agains it.

The glass pane will be held in place by VHB tape and some caulking. No screws and no other support.

Has anyone done this?

I see it regularly done on new modern boats, even on rounded/curved windows.

We have been looking into this as well.
There is a local company to me that will cut the glass and polish the edge. They sell the glass with a special glue that has a fancy tip on the cartarage. It leaves a nice little diamond shape. This way you have the proper gap when cured for flex. I have seen one other boat change out to this style. They cut out cardboard for a templet and held a 1.5 inch tint on the inside edge to hide the glue line.They used some suction cups on the inside and tied tham back to the far side of the boat. And some scrap wood as a bottom base to keep them from sliding down. Looks very nice when done.

In the RV world, frameless window have taken most brands over.
To see how they are attached, a visit to an RV lot with newish RVs will get you access to many examples.

When I was selling my 1982 Seabird, I had to re-seal all 19 Aluminum windows, so I gat to see how that process worked. Butyl tape was the whole answer. Even where the frame didn't fit tightly to the opening, the butyl tape had sufficient give and flow to be both adhesive and caulk. Far less work, but the finish stayed 1982, not 2021.

Definitely seeing this more often. A builder I've had discussions with in Turkey for a trawler uses frameless on all their commercial boats. I was wondering how sufficient this would be for a bluewater vessel however in heavy seas and cold winter gales. Perhaps there have been some white papers published on this subject?

Sika is an important player in the frameless glazing industry - sky scrapers have done this for a while. The bead needs to be a certain width and thickness that varies by glass size to accomodate expansion. I understand the caulk itself is a bit tricky to work with and some special forming tools are helpful to make an attractive bead.

Here is a PDF from Sika. There are others, but this is one I found quickly.

https://usa.sika.com/content/dam/dms/us01/d/Bonding and Sealing Plastic Windows.pdf

Peter

I looked at bonded in windows years ago, talked to the Sika rep and, I think, the Garibaldi glass rep. Their process was to pot the glass in a rabbet using a pretty thick layer of goo. The thickness of goo allows for expansion and movement between the boat and window. They also spec that the bond be to a ceramic frit on the glass. It looks to me that that's the same process used in architectural bonded in windows.
It sounds like the OP wants to plant the glass on the outside of his cabin using two sided tape. I'm skeptical.

koliver said:

In the RV world, frameless window have taken most brands over.
To see how they are attached, a visit to an RV lot with newish RVs will get you access to many examples.

When I was selling my 1982 Seabird, I had to re-seal all 19 Aluminum windows, so I gat to see how that process worked. Butyl tape was the whole answer. Even where the frame didn't fit tightly to the opening, the butyl tape had sufficient give and flow to be both adhesive and caulk. Far less work, but the finish stayed 1982, not 2021.

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Thanks Keith,

I used 3/8" Butyl tape in my frames and I agree, it is pretty sticky and perhaps provides good adhesion and sealing but I believe that my aluminum window frames may have developed cracks or cavities resulting in leaks. Butyl is however very messy to remove. I've spent hours removing the original one.
I do not think it would work for the application I have in mind. 3M VHB and higher end caulking(I cannot recall the brand right now)is what I have in mind. butyl can also sag in the heat which would result in window pane dropping unless something more adhesive is used.

I was sceptical too until I've seen the various applications for 3M VHB tape.It is used on trailers, motorhomes and even busses which are attaining much higher speeds and go through some 'bumpy rides'. it is typically used where screws and rivets used to be applied for securing. in the days my boat was built (1980) only few have envisaged the affordable technology that exists today.

i used the 3m urethane automotive glass adhesive to mount a couple of windows recently. you do need to make sure to protect it from uv exposure though. the ceramic frit on auto glass does a good job of it, but i used wood trim to do it from the exterior, as i was re-using the glass i had. we'll see how it holds up.
the vhb tape is very good stuff, but the glass would need a perfect fit against the cabin side so there aren't any voids. there are thicker versions of the tape, but thicker loses strength.
if you're going to have to re-shape the openings anyway, i would consider making a shape the glass could fit into that flushes with the cabin side. then use the 3m (or sika if it's as good ) auto glass adhesive. i contacted a glass manufacturer a while back and they will make fritted glass of any shape.
you cut the tip of the caulking tube to a triangle shape to apply the adhesive. it puts the perfect amount on. glass secured with that sealant is actually a structural element on your car.

sean9c said:

I looked at bonded in windows years ago, talked to the Sika rep and, I think, the Garibaldi glass rep. Their process was to pot the glass in a rabbet using a pretty thick layer of goo. The thickness of goo allows for expansion and movement between the boat and window. They also spec that the bond be to a ceramic frit on the glass. It looks to me that that's the same process used in architectural bonded in windows.
It sounds like the OP wants to plant the glass on the outside of his cabin using two sided tape. I'm skeptical.

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My buddy used Sikaflex 296 with a specal tip to create the right size finshed gap. Looks increadable. But the glass cost is high.
Same process as what the sky scrapers use for flush mount structrual glass.

The issue that has been proven in the sailboat and catamaran area is that the seal on these frameless windows only lasts about 10 years. Then you have a huge job of ripping them out and doing the job all over again (see youtube "sailing with the Wynn's").
Perhaps a better custom frame design is needed so that leaking will not occur?

Bmarler said:

i used the 3m urethane automotive glass adhesive to mount a couple of windows recently. you do need to make sure to protect it from uv exposure though. the ceramic frit on auto glass does a good job of it, but i used wood trim to do it from the exterior, as i was re-using the glass i had. we'll see how it holds up.
the vhb tape is very good stuff, but the glass would need a perfect fit against the cabin side so there aren't any voids. there are thicker versions of the tape, but thicker loses strength.
if you're going to have to re-shape the openings anyway, i would consider making a shape the glass could fit into that flushes with the cabin side. then use the 3m (or sika if it's as good ) auto glass adhesive. i contacted a glass manufacturer a while back and they will make fritted glass of any shape.
you cut the tip of the caulking tube to a triangle shape to apply the adhesive. it puts the perfect amount on. glass secured with that sealant is actually a structural element on your car.

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I will go with 1/4 " glass or plexiglass so not sure the fibreglass hull at the window opening is that thick to rout it and make the glass/plexiglass pane flush with the cabin side. That option seemingly provide support and certainly better appearance being flush with the cabin side, but the pane will still rely on VHB and, to some extent, caulking on staying in place.I guess the ceramic fit is not available with plexiglass and I will check what sort of UV protection I can apply to inside of plexiglass to protect from UV and have adhesion to VHB tape, if I go that route. The additional cost for ceramic fit on glass windows may be prohibitive cost...

Taras said:

The issue that has been proven in the sailboat and catamaran area is that the seal on these frameless windows only lasts about 10 years. Then you have a huge job of ripping them out and doing the job all over again (see youtube "sailing with the Wynn's").
Perhaps a better custom frame design is needed so that leaking will not occur?

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Try doing the job that Hatteras recommends for their aluminum framed windows resealing and you will think that removing the caulking and VHB tape on a window pane fitted over a smooth painted or gelcoated fibreglass is a piece of cake. The original fitting (as well as retrofitting) calls for a sponged tape on the inner edge of the frame, and Butyl tape on the outside closer to the edge of the frame) then you place the glass/fiberglass pane on top of that, then you fit the rubber edge seal, and hot iron the corners. The fitting is easy. Removing the glass pane after 40 years sitting on Butyl tape is an undertaking to say the least. Out of 5 windows I attempted to remove, four broke and I needed to replace and the fifth one I did not remove, but replaced only the rubber corner seals. It looked good and was probably best method back in 1980 but not today with technology we have at our disposal. 3M (Minnesota Mining & Manufacturing) is one of the most inventive companies I know of that has been around for a long, long time.

Still would like to know more about the strength compared to frames windows. It would be horrible to have a window pop out after get to my hit by a whollap of blue water during a nasty storm.

This is exactly what I am doing with my boat and the exact same plan.
I have no doubt about strength if done properly, most of automotive windows are set like this and usually the window itself breaks before the bond.
However the important thing is: if done properly, as VHB tape needs to be used in the right way.
Beyond that is also what boat usage it is intended to, in my case I doubt I would be in such bad condition that I would be concerned about my portholes or windows.

L

Bmaler is right. We have looked at forming a company to make glue in windows for high end yachts with aluminum windows that are failing. Nordhavn, Selene, Kady K, etc.

This is very common, and easily fixed today. Of course easy and expensive do sometimes go together.

This is worth a read before going too far down the road thinking that bonded in windows are the easy answer. It pretty much convinced me that in order to do it correctly and be pretty confident in long term success that you really need to be designing the window openings, flange width, rabbet depth etc, for it from the beginning.
https://industry.sika.com/content/d...3/4_Structural_Bonding_Marine_Application.pdf
I know that you're looking at 3M but I can't imagine that their tech is significantly different.
There is a guy with a Rawson 38 next to me who had some window guy out of Seattle pull and rebuild all of his aluminum framed windows. Did an awesome job, all the work and install looks great. I'd look long an hard for someone like that in your area before anything else. Heck, you're in BC call Diamond Sea Glaze and ask them if they can suggest someone

Taras said:

The issue that has been proven in the sailboat and catamaran area is that the seal on these frameless windows only lasts about 10 years. Then you have a huge job of ripping them out and doing the job all over again (see youtube "sailing with the Wynn's").
Perhaps a better custom frame design is needed so that leaking will not occur?

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I think it was 8-10 years, the leaks started a while back, certainly not great advertising for the yacht brand, the cracking Perspex or the adhesive. Around $1500 just for the new adhesive alone, without all the leak dramas at sea and ongoing fixes.
I noticed they used FixTech caulking, a brand which is very popular in the Southern Hemisphere

You mention "glass"; have you given any thought to using MarGard Lexan or one of it's many clones.
More transparent than glass.
10X as strong
Will conform to curved surface
You can cut it yourself
Wipers will not scratch it
Lightweight
Drillable for screws, storm shutters, exterior shades...
Does not discolor at the edges like safety glass



I have used it on several boats and always had satisfactory results using both Lexan's own sealant or black silicone or black LifeSeal, the latter being the strongest. Black looks good as a frame.


I have also used it in 1/2" and 3/8" thickness for top hinged opening windows that simply land on EDPM weatherstrip on the substrate.

OP, you might want to compare the price of these new materials vs ordering all new framed windows from China or India. Even with shipping it may be comparable.

Brico said:

The glass pane will be held in place by VHB tape and some caulking. No screws and no other support.

Has anyone done this?
.

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I had all my forward windows replaced this last summer. 8 in all using a similar method. I watched the installation. You only get one shot at getting the windows correctly placed which was a huge issue for my very large windows due to their weight, the angle and the access. We had a scaffold, 5 guys and a lot of hesitancy before taking the plunge. Your windows are smaller obviously but if you go that route you need people inside the boat and outside the boat, all with suction cup grips on the glazed window. Your windows should have blackout all around the outside which will protect the sealant on the inside of the window (this is critical). My windows failed due to the lack of UV protection of the 25 years old sealant. The sealant, where not exposed was still good, but where exposed had hardened and lost integrity.

I've attached picture of the prep.

AlanT said:

I had all my forward windows replaced this last summer. 8 in all using a similar method.

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This is great to hear and increases my confidence in this being feasible and doable job. My windows are certainly smaller ands lighter. 3M Technical people told me that static strength of the 3M VHB tape is 4 square inch per pound and 12 square inch per pound for dynamic strength. Considering the length of tape 3/4" tape and the weight of the windows, I'll be OK and caulking will add up to the strength as well.

Great Link

Great link, THANK YOU!

mvweebles said:

Sika is an important player in the frameless glazing industry - sky scrapers have done this for a while. The bead needs to be a certain width and thickness that varies by glass size to accomodate expansion. I understand the caulk itself is a bit tricky to work with and some special forming tools are helpful to make an attractive bead.

Here is a PDF from Sika. There are others, but this is one I found quickly.

https://usa.sika.com/content/dam/dms/us01/d/Bonding and Sealing Plastic Windows.pdf

Peter

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I was quoted about 7k to do all new frames and glass for my 2 long saloon windows on my Hatteras 48 LRC. Given the scope I thought it was not too bad. I saw a boat they did and it looked very nice.

Fyi I believe in most cases Hatteras just cut out the openings and installed the windows. They did not fill or glass the cut edges. That is what I found when we pulled the pilothouse windows on my former 1977 58 EDMY. I had the yard fix that.

These are overlaid, held in place with a double row of VHB and caulked with 5200 to seal edges. Used Krylon paint to black out the edges, it is formulated to bond with plastics. No leaks or problems with the bond since 2016.
I used Lexan 3/8”, due to some irregularities in the framing, surface was not entirely flat, and I was afraid that glass would not flex enough.
That was a mistake, the tropical sun destroys the surface, and it requires major compounding and buff every other year. Also scratches too easily to run wipers.

I have not had good success with using 5200 on plexi or lexan. I use Sike 295UV.

I have done several sail boats windows both with recessed and surface mounting using polycarbonate glass . The expansion and contraction is considerable! The VHB tape has some foam in it that allows for some movement and is more than adequate to hold in place. If you use polycarbonate Dow Corning 795 caulk is what I have used with great success. Follow the instructions you must insure that you have a large caulk line to accommodate the expansion and contraction your your caulking bond will break. If you choose to use tempered glass as I have on my trawler that incorporates a wood frame to trim it I used Sika 295, it's paintable. All of my installations have been time tested and best of all no leaks.

I replaced and rebuilt all the windows on our GB.

At the time I considered glue in. Would have been very easy.

I also thought about making new frames out of extruded fiberglass. Easily shaped by common woodworking tools and glued. Awlgrip it and never touch them again.

Only reason I didn't was my frames came off so easy, and once I used penetrating epoxy on the frames, they became hard as a rock.

You can go to my blog, grandbankschoices, and see the process. It is not easy, but not physical. Took roughly 24 man hours per window, and I had 20.

Choices blog is a good one on a how to. I am a big fan of VHB tape I used to set the laminated glass in to maintain the gab needed all around the glass before caulking/bedding the exterior wood trim in Sika 295 over the glass. If you use a penatrating epoxy on the wood frame and then paint you have created a very durable and relatively inexpensive system. You might explore the difference in cost of laminated glass versus polycarbonate or equivalent.

It is my understanding that VHB is used to adhere windows in skyscrapers. Good enough for that application, good enough for me. I did use it on my sailboat with recessed ports and finished off with BoatLife. Smaller application but it never leaked.