Will my windows explode?

[Shuggy]

I've got glass windows screwed into a teak superstructure. They're slightly curved (i.e., the teak is curved and they lie on top of the teak) - I hope this photo illustrates it, but don't confuse the high -> low 'sweep' with the curve in the same plane as the frame:

They are leaking slightly so I'm going to have to re-bed them. The question is - how do I remove and re-fit them to avoid shattering them when relieving the stress, or indeed screwing them back in?

Is the secret to take each screw a half turn at a time all the way round? Or does the esteemed panel think it'll all be fine however I do it?

Thanks.

 

[Lakesailor]

Gently from the centre to the ends. (Doing up. Opposite undoing)
If you have watched glaziers cutting 8x4 sheets of glass, it is surprising how flexible it is. Just the sudden loads that upset it.

You have tried Captain Tulley's, first?

 

[Shuggy]

Captain Tolley's creaking crack cure has been applied liberally! I keep applying more, but I think the seals are shot. But thanks for the pointers on which way to do up/undo.

 

[VicS]

Tighten the fastenings progressively a little at a time to avoid any stress, as you suggest

 

[PlankWalker]

You shouldn't have a problem with the glass, it will revert to being straight when removed.

The frames will retain their curvature however and you may find it easier to straighten these before re-bedding and refitting to a curved shape.

Plank

 

[Deleted member 36384]

It is possible that the glass has been moulded with a curve in it especially if its toughened glass (kite mark symbol on one corner). As the glass is a small surface area and about 5 mm thick, it really does not like to be bent at all. Further, to ensure a seal between the glass and frame the glass has to be more or less uniform within the frame channel for the seal to work i.e. the frame can not be used to bend the glass or the seals wont work.

I would recommend that the frames are bedded with Scapa 3507 bedding tape. The tape is 3 mm thick and compresses down by about 2 mm, so you need to purchase new screws about 3 mm longer. Screws from http://www.a2a4.co.uk/

One think to consider if the glass sits inside a frame channel i.e. not butted between the frame and coach roof), is that the leak path could be between the glass and frame. I found (on aluminium frames) that parts of the channel had perforated with corrosion and the water was running between the glass and frame seals and out through the hole in the frame channel.

Regards,

BlowingOldBoots

 

[sarabande]

thanks BoB, i hadn't come across that sealant tape before. Looks good. Anything to avoid a cock-up with exploding glass windows.

 

[pvb]

Surely it's going to be toughened glass? If it isn't, you'd be well advised to replace it with toughened glass or some sort of plastic.

 

[sarabande]

Lexan flexes, and is much more resistant to point impacts. UV protection also available in some sheets as well as shading.

http://www.gcip.co.uk/EP/lexan_polycarbonate_sheet.htm

Good suggestion, Pvb.

 

[vyv_cox]

The windows on your boat appear almost identical to the ones on my Sadler, also fitted on a curved surface. I have removed, sealed and rebedded mine countless times and never had a problem (except fixing the leaks!).

Firstly, make absolutely certain that the leaks are between frame and coachroof, not between frame and glass. The glass seals break down over time. Although I have been moderately successful in rebedding the glass in the frames I now wish I had used a professional to do it when I had the opportunity. Eagle Windows seem to come highly recommended for this.

I have always used Sikaflex 291 to bed the frames onto the coachroof, although I concur that a non-setting mastic would be better. Next time I do the job that's what I will use. Removing the frames is not particularly difficult, even with a strong adhesive like Sikaflex, it's just a matter of going slowly and inserting thin wedges to shear the adhesion. Toughened glass is remarkably robust, I would guess it's less likely to be damaged than the frame.

 

[Shuggy]

Surely it's going to be toughened glass? If it isn't, you'd be well advised to replace it with toughened glass or some sort of plastic.

Yes, I think it is. It has kite marks.

I would recommend that the frames are bedded with Scapa 3507 bedding tape. The tape is 3 mm thick and compresses down by about 2 mm, so you need to purchase new screws about 3 mm longer. Screws from http://www.a2a4.co.uk/

One think to consider if the glass sits inside a frame channel i.e. not butted between the frame and coach roof), is that the leak path could be between the glass and frame. I found (on aluminium frames) that parts of the channel had perforated with corrosion and the water was running between the glass and frame seals and out through the hole in the frame channel.

But thanks, BoB, for the Scapa 3507 tip. I'll buy some once I've got them apart and seen how they fit together. The glass is butted against the wood - at least, all you can see from the inside is wood and glass, no frame.

 

[captainboo]

Window Bedding

I have just refitted all 8 of my windows to the boat. They look very similar to yours. They are made of flat toughened glass in an aluminium frame.

When offered up to the boat and touching in the middle there was a good 10mm gap at either end of some of the smaller windows that needed the window to be pulled back to shape by progressively tightening the screws from the middle out, alternately top and bottom edges.

They were bedded down on the aforementioned Scapa Bedding Tape. Once pulled into shape and the tape evenly compressed (30-50%) around the whole window, each screw was backed out individually by a few turns and sealant injected under the head and re-tightened.

The windows were all re-bedded in the frames by Hadlow Marine Services who also supplied the bedding tape with comprehensive instructions on how to use.

Only fit the tape to the windows just prior to putting back on the boat. I did mine a few weeks before and although I took great care not to stretch the tape at all whilst applying it still shrank slightly at joins requiring small pieces to be inserted just before re-fitting!

 

[Shuggy]

Only fit the tape to the windows just prior to putting back on the boat. I did mine a few weeks before and although I took great care not to stretch the tape at all whilst applying it still shrank slightly at joins requiring small pieces to be inserted just before re-fitting!

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