Sealant for windows

[bob_tyler]

I am looking at renewing the windows (correctly ports?) in my cabin top. The present ones are crazed and unsightly.

I am a great fan of Sikaflex for sealing but cannot see how to make it look tidy from the outside under the transparent Perspex.

Many years ago when I built my Trident 24 I bought a roll of strip sealant which I used on that boat for many fittings above waterline with complete satisfaction.

What I think I need is a seal, rather like draught excluder, which would squeeze out evenly along it's length but not squash unevenly, if you see what I mean.

Any suggestions about make, supplier etc. gratefully received.

Bob

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[Talbot]

3M make it. neoprene in the middle and sticky on both sides. Comes in a very wide roll which is normally sliced to the width required at a wholesailer. I found one in Shoreham a couple of years ago, but cant remember the name, ask any double glazing specialist and they will know. Makes the final result look good!, but it is not cheap. alternatively, screw window on without glue then apply masking tape to inside and outside of window. remove window, apply the correct sikaflex (not the normal one, it is a special UV stabilised one), screw up loose so it is bedded properly but not squeezed, remove masking tape and leave to cure, then tighten a tad more - end result a neat and good looking seal.

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[Nigel_Ward]

I am just in the process of replacing the windows on my boat. I bought sheets of neoprene from http://www.sealsdirect.co.uk. They sell all sorts of seals and I am sure will have what you want.

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[Stemar]

If the frames are too far gone when I do my boat, I thought of using an oversize sheet of perspex screwed directly the cabin sides, but am a bit put off having seen some truly horrible jobs.

I thought about cutting out my windows as above and drilling for the screws, then masking the part I want to be transparent and painting the "frame" black on the inside. That way the mastic or whatever will be hidden.

<A target="_blank" HREF=http://www.sealsdirect.co.uk/bbCMS/shopping.asp?intDepartmentId=4>Seals Direct</A> have something called Porthole rubber strip that looks as though it might do the job, but it isn't clear if it's self adhesive

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[Talbot]

if you paint the frame black on the inside, you are relying on the adhesion of the paint to the acrylic for the seal - not a good plan. why not do it the way I recommended above, but use a black sickaflex (agin make sure it is the correct one for windows)

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[john_morris_uk]

If you bed the perspex on Sika Flex window sealant and wipe the excess off using white spirit as a lubricant you can end up with perfect seals that look neat. (You have to use lots of cloth/kitchen roll, and the white spirit doesn't dissolve the sika flex, but allows you to make a clean neat joint edge.)

It also tends to get everywhere when you are doing it, but you'll be quite good at the technique by the time you've finished!

Some people leave the screws 'noy quite tight' until the bedding compound has set and then nip them up.

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[Stemar]

Since I'd be using screws to hold the windows on, all the sealant would do is to keep out the weather, and it would be in compression. Is the paint adhesion likely to be an issue in these conditions?

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[simonfraser]

make sure the screw holes in your windows are big enuf to allow for expansion, else the ss screws will crack the window

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[Talbot]

Its the sealant that keeps the water out! in fact if you use the right sealant, you dont even need the screws.

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[bob_tyler]

"you'll be quite good at the technique by the time you've finished!"

That finally rules out Sikaflex, you have convinced me.

I don't want only the last window I fit to appear OK but right from the first one.


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[misterg]

I used self adhesive neoprene strip from ASAP. (Cheaper from ARCO if there is one near you.) Stick it to perspex, & tighten screws down gently + evenly. No mess, looks good, and 12 months on, no leaks.

Andy

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[BigLes]

I recently did this job on my Bennie where the windows are bonded directly to the GRP surround. For the Sikaflex to work (I used 295 UV as it's UV resistant) you will need to use a primer (from Sikaflex) on the GRP surround and also on the Acrylic/Perspex windows. The Sikaflex will not make a watertight joint on the Acrylic/Perspex without the primer - I know becuase I did the job earlier in the year without the primer and the Sikaflex parted from the windows and leaked! I used wide masking tape around the grp surrounds to capture any excess sealant, and used small pieces of shaped Formica to fair-off the sealant. In my case the windows are temporarily held in place with screws through to the grp, however these are later removed and the holes plugged with Sikaflex. These windows are along and up and over the coach roof so re quite large and are now completely water tight. Needless to say the primer hides the sealant when viewing from the outside.

Hope this helps.

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[john_morris_uk]

What I meant was keeping the mess off you!

With a little patience and lots of cloths and white spirit you can make every one perfect.
<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by john_morris_uk on 05/12/2004 13:22 (server time).</FONT></P>

 

[LeonF]

Use the neoprene tape! I bought the Sikaflex to use for the screw on windows on myprevious boat a Sigma33, but was reluctantly persuaded to use the neoprene and it worked a treat. I also drilled into the original self tapper holes and and used interscrews. Salford House Windows sell it too ...they advertise in the back of PBO

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[AndrewB]

I've never had much luck with neoprene seals on windows, they seem to leak again pretty quick, specially at the corners. Personally I'd go with Sikaflex 295 even if it doesn't look quite so neat. Perhaps you could stick or paint something on the outside of the window edges to hide the appearance beneath?

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[bob_tyler]

Thanks to all for the replies above. The product that I used in the 70's for bedding my Trident's windows was rather like a roll of plasticine and most effective and neat.

That's what I am trying to find now. As far as I remember it was about 1/4 or 1/2 inch wide.

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[Guest]

B&Q

Sink sealing strip - the type that goes under the lip when fitting to work-top .......

<hr width=100% size=1>Cheers Nigel ..... <A target="_blank" HREF=http://www.geocities.com/solentlifeuk/>http://www.geocities.com/solentlifeuk/</A>

 

[bob_tyler]

Re: B&Q

Many thanks Nigel, the definitive answer. I remember now that I bought the last lot 30 yrs ago from a plumbers' merchant and it worked perfectly.

It probably gets an easier life on the outside of a boat than it does waterproofing the joint between a sink and worktop indoors.

It will also be a LOT cheaper!!!

Cheers, Bob

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