How do you reseal a bonded windscreen?

[Deleted User YDKXO]

My boat has a one-piece windscreen which is bonded in it's aperture onto what looks like an L shaped rubber moulding. During the last 2 years or so, water has begun to leak past one of the lower corners of the screen into the cabin below. I have tried applying sealant over the top of the exterior face of the rubber moulding in an attempt to seal any gaps between the moulding and the glass. This worked for a while but the leak reappeared. Then I tried scraping away perished areas of the rubber moulding adjacent to the area that was leaking and filling with sealant but this only worked for a few months as well
I have been told that the whole screen needs to be taken out and rebonded but, obviously, this is a major job and I am worried about how the screen can be handled because, being a single large pane of glass, it's going to be very heavy
Anybody got any ideas?

 

[Cliveshep]

Do you have an automotive screen outfit near you? Your screen will have to be removed, surround and glass properly cleaned off and then re-bonded. Although large it is probably no larger than the bonded windows on buses and coaches. Perhaps a bus company can point you in the right direction?

 

[jfm]

My boat has a one-piece windscreen which is bonded in it's aperture onto what looks like an L shaped rubber moulding. During the last 2 years or so, water has begun to leak past one of the lower corners of the screen into the cabin below. I have tried applying sealant over the top of the exterior face of the rubber moulding in an attempt to seal any gaps between the moulding and the glass. This worked for a while but the leak reappeared. Then I tried scraping away perished areas of the rubber moulding adjacent to the area that was leaking and filling with sealant but this only worked for a few months as well
I have been told that the whole screen needs to be taken out and rebonded but, obviously, this is a major job and I am worried about how the screen can be handled because, being a single large pane of glass, it's going to be very heavy
Anybody got any ideas?

Mike I'm confused about it being bonded onto rubber as opposed to onto the boat directly. I mean what attaches the rubber to the boat? Is the rubber a bridge twixt boat and glass?

Anyway I had this prob and Trend Marine said only proper long term cure is to refit the whole glass. Mine is bonded to boat grp, no rubber, so they covered the glass in sticky tape and smashed it with hammer. Then scraped out the bits then fitted new glass using a sika adhesive (can't rem the number but I have it somewhere). Since then its been great

I'm sure you didn't want to hear that. Anyway my thought would be to do as you've done. Fix it by carefully applying sealing goo. But don't use silicone sealer. Use the much more serious sika adhesive sealer. This is the stuff car windows are stuck in with

 

[DavidJ]

A problem I had with my Sealine screen sounds similar and it leaked finding it's way down to the master cabin.
Can you pull back the rubber that presses against the screen (on the outside). I did this and put a layer of sikafex into the 'well' all the way along and a cure was made which has lasted 3 years now. I think this is different from what you decribed as I think you applied the sealent to the outside.
All a bit difficult to describe but may be of help

 

[Deleted User YDKXO]

Mike I'm confused about it being bonded onto rubber as opposed to onto the boat directly. I mean what attaches the rubber to the boat? Is the rubber a bridge twixt boat and glass?

Anyway I had this prob and Trend Marine said only proper long term cure is to refit the whole glass. Mine is bonded to boat grp, no rubber, so they covered the glass in sticky tape and smashed it with hammer. Then scraped out the bits then fitted new glass using a sika adhesive (can't rem the number but I have it somewhere). Since then its been great

I'm sure you didn't want to hear that. Anyway my thought would be to do as you've done. Fix it by carefully applying sealing goo. But don't use silicone sealer. Use the much more serious sika adhesive sealer. This is the stuff car windows are stuck in with

As far as I can tell, the glass is bonded into this L shaped rubber moulding and the moulding is bonded to the grp. What seems to have happened is that the glass has slightly de-bonded from the moulding in the corner where the leak is. You're right. I don't want to hear about smashing windows and buying another screen from Ferretti as I'm sure they're talking telephone number prices! I'm not even sure I could get one as the screen is curved and has shading around the edges and the F46 went out of production some years ago
Good advice about the sealant. I have been using silicone sealant so maybe a better sealant would do a better job. Anyway sounds like only course of action is to bodge it again and try harder to sell the boat!

Thanks to other posters for their replies

 

[MapisM]

You're right. I don't want to hear about smashing windows and buying another screen

Quite understandably.
If the sealing doesn't work, one possibility to remove the screen in one piece (to refit it afterwards) is to use a thin but strong enough nylon cable, firmly attached to two handles, one on each side of the window. It takes two people and a lot of patience, but using the nylon to cut the rubber, you can detach the glass without risking to break it.
Good luck with the sika anyway.

 

[Observer]

Don't know how serious your leak is. I have a slight leak from a side window. Not sure how it's fixed except it has S/S frame. From the outside, I can see where the frame has 'pulled away' a little and there is a gap of 1-2mm in the sealant below about 3" long. I'm going to try Capt Tolley's leak sealer (recommended on a thread elsewhere) as a low cost cure but may have to look at something more drastic (and no doubt expensive) if that doesn't work. Fortunately, the area below the leak is a hard surface so no water damage.

 

[PCUK]

Use the correct sealant. I can't remember what it is called but there are several for bonding rubber and glass. Scrape and fill as you have already done. I did mine 12 years ago and still water-tight!

 

[rlw]

If you need to go the route of cutting out the windows check with a car/bus window outfit. They use a similar system as the nylon cord described but then the pro version. I had a new windscreen put on my audi and they had a contraption with suction pads that fitted on both sides of the window and then fed a fine steel cable through the frame and turned a handle and it only took 5 minutes to cut out the screen. The cable was actually equipped with 4 cutting edges. The cut was so clean all he did was glue a new bead of sealant in place and fit the new windscreen. I salvaged the cutting cable from the trash in case I ever need to remove the windows on my boat. Was facinating to watch the ease with which it was done. Toolkit looked expensive though. They come onsite with a mobile workshop. In my case I offered the guy the use of the garage in case it rained but he told me he generally prefers to do it outside as it only takes half an hour start to finish.

Rob

 

[rafiki_]

Best advice was earlier in the thread, talk to Autoglass or similar. Pretty much all automotive screens are bonded in, and replacement glass people can cold bond. I guess it is bonded to a rubber seal to allow for some flex. If it was bonded to the grp, then either the grp or glass would crack as the grp flexes.

 

[moonraker 36]

HI ALL. the sealent every one is talking about is a polyurethene addisive very strong,black in colour. you need a primer to get good adhesion.the best way would be to remove the glass.wont be as heavy as you think and no way as near as heavy as a coach screen (i no i replace them lol).if you have used a silicone sealent you will need remove all of this as the polyurethene addisive wont stick to silicone at all.the wire used to remove windscreens as discribed above is the best way to remove the glass,but if you kink the wire it will snap very quickly. if you were closer i would do the job for you for a fair price.
moonraker 36.

 

[bigwow]

My windows are glass in an aluminium frame. When two of them started leaking, in between the glass and the frame I raked out, from the outside all I could. Then cleaned the slot with a scotchbrite pad, very tedious. Next prime with Sikaflex activator, mask well then fill the slot with Sikaflex 255. Job done!