Just to check my facts on window sealing

Durcott

Durcott

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Hi Folks,

this is a bit of an old chestnut topic, but I just need to check a 'fact', and I'd also be grateful for any comment.

This concerns refitting the glass into its aluminium frame on a Sadler 32.

The frames are quite old, and fairly corroded. I've given up the idea of remaking the original gaskets - it seems likely these wouldn't seal unless the frames were in much better condition.

Having looked up many threads on window sealing, including a good load of information on the Sadler owner's forum, I reckon a product like Arbo Mast is ideal for re-sealing the frames onto the grp.

But what about sealing the glass against the frame? The frames seem to have a shaped rubber insert to hold the glass. This must have perished years ago. (A previous owner then plastered on sikoflex, allowing trapped water to attack the aluminium). Some threads have hinted that a Butyl Rubber sealant could also be used for the glass, but it's not stated definitively. I was hoping I could use a little scrap wood to position the glass, and then use sealant to bed the glass and make the joint waterproof.

Unfortunately it's taking a while to get registered on the Sadler forum, so may I ask if anyone here had any joy in using a Butyl Rubber sealer on a glass to frame application?

Thanks

Jeff
 
The butyl rubber compounds I know remain soft .... a soft and very sticky mastic. I wouldn't use them unless the glass is otherwise mechanically restrained from popping out. It is an excellent sealant, although somewhat messy to use .... when pulling the nozzle away you'll get multi-strands of sealant between the nozzle and the job. Keep some turps or white spirit handy for cleanup.

I don't know the frames you are talking about .... but if you can get 5mm all round the sides of the glass, I would use sikaflex 295iuv with the appropriate primers. It is a much cleaner method and doesn't ooze out of the joint as the glass moves.
 
Durcott said:
But what about sealing the glass against the frame? The frames seem to have a shaped rubber insert to hold the glass.
Click to expand...

Seals Direct almost certainly have what you need at http://www.sealsdirect.co.uk/shopping.asp?intDepartmentId=3#21 which says "For protecting edges on panels, doors, glass, etc. It is also suitable for making a seal around glass in Aluminium window channels." If the insides of the frames are manky you can use some sealant as well as the rubber.

Fitting the seal to the glass is pretty straightforward: you cut to size and then glue the ends with superglue. Alternatively it might be worth getting a quote from a window company. I've had two sets of aluminium framed windows (Westerly and Hunter) rebuilt by C&J International Windows, who did a lovely job both times and charged surprisingly little.
 
Unfortunately it's taking a while to get registered on the Sadler forum, so may I ask if anyone here had any joy in using a Butyl Rubber sealer on a glass to frame application?


Sorry can't help with the windows but yes - what exactly is the problem getting registered on the Sadler forum?
I have been trying for weeks/months and no replies or enablement to "log in".
 
Abormast BR for the frames. Butyl double glazing tape for the windows. All the benefits of butyl, but much firmer and not as messy. Alternatively, black marine silicone.
 
Sikoflex make a product specifically for sealing glass into frames (Arbo probably do to). My aluminium window frames sound similar to yours and were fully refurbished. The old gasket type O ring that held the glass in place had failed. The refurbisher inserted the glass on a bead on one side of the frame, then filled the frame on the other side after the bead set. The glass and frames are now well bonded with no air gap inside the aluminium channel.

This is the tape that you can use to mount the frames onto the hull http://www.arbo.co.uk/arbo-sealants/arboseal-gz-tape/
This is what my window refurbisher Hadlow Marine used (it can be bought from him): http://hadlo-43547-001.dsvr.co.uk/Pages/seals-bedding.html

I had excellent service from Hadlow Marine, no connection except as a satisfied customer. All the stuff you need is available from this place.
 
About the registration, are you using the current forum address? http://mly.gamalanhost.net/forum.asp?FORUM_ID=3

I have resealed the windows on my Sadler 34, which I believe are the same on the 32, many times. You may be able to find my description of doing it on the S&SOA forum. However, it has never been 100% successful, particularly in Greece where the high temperatures increase the expansion of the aluminium, making things even worse. The original sealing on these windows was made with a liquid mastic. Most people, including me, have attempted to use the same method but it is very difficult to achieve good adhesion between the glass, frame and sealant without baking them in an oven, which is the method the professionals use. It is also necessary to use a special primer, which can be supplied by Eagle Windows.

It is not an easy job to separate all the parts because the frames slide endways over the glass, joined by a fish-plate, rather than by bolting the front and back together as with other types. Everything then needs to be cleaned meticulously and reassembled without sealant. Re-sealing needs to be done in two steps, front first, left to cure, then the back.

Having done this up to three or four times on some windows I have now given up and had it done professionally. Either Hadlow or Eagle are fully capable of doing the work. I have read of one owner who used the Seals Direct moulding, he claimed successfully, but I imagine it might be difficult to get everything assembled correctly.
 
I did the windows on a Sadler 32 a few years ago. Arbomast Br is fine for bedding the window units into their GRP frames on the boat. However rebuilding the windows, that is to say bedding the glass into the aluminium frames is best done with Marineseal 033 which is a two part non setting rubber sealant. Its a bit fiddly but can be done DIY. Aternatively send the old windows to Eagle Boat Windows who will do an excellent rebuild job using this compound.
 
TradewindSailor said:
I don't know the frames you are talking about .... but if you can get 5mm all round the sides of the glass, I would use sikaflex 295iuv with the appropriate primers. It is a much cleaner method and doesn't ooze out of the joint as the glass moves.
Click to expand...

Just out of interest, how easy is it to remove Sikaflex 295UV again if you have to remove the window for some reason? We have frameless perspex windows that are bolted onto the side of the cabin GRP, and I have tried butyl rubber (both Arbomast BR Black and Sikalastomer-710) to seal them but always end up with leaks after a couple of years, so I am thinking now of something like Sikaflex 295UV that is both sealant as well as adhesive.

I have tried Sikaflex 291 in the past, and while giving a perfect seal, was very difficult to remove when I had to replace the window because of a crack. Is the 295UV similar?

Rob.
 
Rob,
I personally avoid any type of adhesive sealant now on GRP unless it is a permanent bond I need. When I removed my windows which were bonded with such a sealant some gel coat came away with the frame. The tape mentioned in my post above has proved excellent at sealing aluminum frames against GRP, even where the frame has to fit over a slight camber on the hull. The boat has stayed bone dry (from the windows) over 2 to 3 years (I refurbished them over a year to spread the cost). The tape is similar to a dense foam strip, slightly tacky but no obvious porosity like foam, comes in various thickness. It was fitted to my windows by Hadlow Marine. I can’t recommend it enough.

Food for thought,

BlowingOldBoots
 
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BoB

Thanks for the info. I did have a look at those tapes and talked to Hadlow Marine a few days ago about what I need (based on your post) - he did actually recommend the Scapa tape, but the self-imposed constraint I have is that I would like the sealant to be black in keeping with the other windows and the overall character of the boat, whereas I think both these tapes are only in grey? I did wonder about the Arboseal GZ mastic (black) that others on here have recommended, but Hadlow Marine said this melts in the sun and oozes out from between window and GRP (not sure that the temperature in Scotland gets that high, but that's what he said anyway!).

I am also not sure about the UV resistance of all these tapes, hence my interest in the Sikaflex 295UV.

I must admit I would prefer a butyl rubber seal for ease of getting it off again as you say, but I haven't had a lot of luck so far in getting a long-lasting seal, unless I am doing something wrong with it. After a couple of years, I get these gaps appearing under the window where the sealant stops adhering and pulls away from the acrylic - see http://shetlandf4.wordpress.com/windows/ for a picture. I do use nylon washers between window and GRP as a spacer, and while that helped a bit, didn't solve the problem completely.

Any advice gratefully received.

Rob.
 
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I use the sticky rubber tape type stuff that is used by window and conservatory makers. don't know what it is called but its cheap and the windows on my boat have not leaked in two years. because it is tape it does not squash if the windows have to bend slightly. i have used sikaflex in the past but it squeezes out of the ends where the window bends and it is a right old mess to use
 
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