View Full Version : sealing windows

18-08-05, 12:49
What's the best sealant to secure alloy window frames to grp cabin? The frames have a flange to overlap the cutout, and the frames are held on by screws. I need to be able to remove them again some time in the future

18-08-05, 12:52
If using Sikaflex, make sure it is the proper one for windows as the normal one at the swindleries has poor UV resistance.

18-08-05, 12:59
thanks - I am reluctant to use sikaflex, after reading of the impossibility of removing later - or is there a specific type for windows?

18-08-05, 13:14
There is a special foam tape about 3mm thick that is used nowadays - I've never used it but apparently very good and not as messy as mastic. Speak to a window supplier and they will probably supply some to you.
Try Hadlow Marine, See http://hadlo-43547-001.dsvr.co.uk/Pages/seals-bedding.html
Never bought this bedding tape from them but they did supply some plastic trim strip which no-one else could. Very helpful, give tham a ring.

18-08-05, 13:36
You are right, if you need to remove them later, do NOT use sikaflex

18-08-05, 13:39
There is a specific type for use on windows. Yes it is hard to remove, but a sharp blade will cut it and can remove 99%, the remainder could either be left as is and new sealant placed on top, or the old stuff fully removed with vigorous rubbing with an acetone soaked cloth - but dont leave the acetone on the grp for very long!

remember to mask up the area you dont want covered with the glop as this will be the most difficult part of the process -- keeping the glop away from bits you dont want coated.

18-08-05, 14:07
Yep, agree with dickh, use the special 'hatch sealing strip' sold by most chandlers. Not cheap, but absolutely perfect for your window job. Used it recently on all my new windows and saved all the dreadful hassle of cleaning up the inevitable excess mastic.

It's adhesive on one side of the foam tape (closed cell) so just stick this side to your degreased frame, offer it up and bolt into place. Eezy peezy! /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif

Hope this helps


18-08-05, 14:20
Bought some from Seals Direct. Can't remember cost but seemed cheap and quick service.

18-08-05, 14:21
Don't use Sikaflex - virtually impossible to remove. Sikaflex is a very strong adhesive. Silicone sealants are not adhesives but are sealants used to fill gaps. I made the same mistake and used silicone on some and when I ran out used this marvellous stuff - Sikaflex !! some of my windows I can now remove to re-bed if they leak and others I can't !

18-08-05, 17:08
Stickyflex 295 UV is the stuff for windows. Whether or not you use it is up to you. I believe that you only use it to fix the transparent bit to the frame. The stuff to fix the frame to the boat is 292.

For God's sake don't get it on your clothing!

18-08-05, 17:13
It works out quite expensive, as it's ~5 a tube, but my best results for sealing anything that you need to remove is Fernox LSX,available from your friendly neighbourhood plumber's merchant. It goes on beautifully and peels off when you remove the bit. Sets like soft silicon rubber. I used it on the wondow frames pf my Nic 26 and it lasted 10 years. when thew sikaflex died around my chainplates I replaced it with Fernox. Not 100% guarantee but I reckon thirty years of sikaflex and four ot Fernox, the water ingress was due to the Sikaflex. It also sealed under my winches and deck fittings to my complete satisfaction

18-08-05, 17:39
the stuff they use for caravan windows is excellent, try any caravan dealer.
lot cheaper too

19-08-05, 06:58
There are many adhesive foam strips available in different widths and thicknesses / hardness etc.

Caravan dealers sell liquid and strip for sealing in windows ...

Kitchen suppliers do sink strip ....

Sikaflex is not advised as it will stick like s to a blanket and you'll regret it if you ever have reason to remove the window again !!

I had a silly drip from one window .... so as a temp fix ran a bead of auto-windscreen sealant round ... it actually ran into the bedding and sealed up a treat .... 3 yrs later I still haven't got round to doing it properly ........ but window hasn't leaked again !!

For some old windows in frames - they used a rubber gasket which 'folded' over the perspex edge ... providing a seal both sides of the window. An old trick was to get an old bicycle inner tube and cut it to fit .... !! joint at bottom of course.

19-08-05, 07:37
'joint at bottom of course'
Why? I should think any shrinking would open the joint and cause a leak. Am I missing something?

19-08-05, 07:53
I agree with others - do not use Sikaflex whatever you do! Apart from being stupidly expensive, it is just the wrong product for the job.

I have refitted all the aluminium windows on my boat. The windows were made by Houdini Marine Windows, Southminster, Essex. The mastic they supplied for the job is called Arbomast BR. In 2002 it was 5 per tube inc VAT. It is a non-setting mastic made for the job which allows removal of the windows at a later date. I suggest you contact Houdini on 01621 773590. Ask for Charlie Stuart - he is very knowledgable and helpful.

Click here (http://www.houdini-marine.co.uk/) for Houdini's website.

19-08-05, 07:54
Exactly, for that reason I would think. If you join at the top any gap would leak in, whereas at the bottom water shouldn't be able to get in unless the boat was upside down.

19-08-05, 08:04
I thought any water that gets between frame and glass finds its way into the boat, and a joint at the bottom is likely to collect more water than one at the top.
At least, that was where I thought one of my windows was leaking. It has a rubber seal which envelopes the glass inside and outside. Did temporarily fix it with a bit of vaseline on the rubber, but still looking for the right way and the courage to take out the window and fix it for good.

19-08-05, 09:10
I'm talking about the sealing strip ... put it at top and instant leak .... put it at bottom as any normal sealing / item involving joint etc.

I'm completely lost by your reply actually - what shrinkage and why do you think joint at bottom is wrong .... ??

19-08-05, 20:02
A chap in Sevenoaks sells the neoprene tape and sealant
Don't remember the name advertises in PBO

22-08-05, 20:28
Definitely use the neoprene tape, 3mm, sticky side to the GRP, don't drill the tape, just a light prick with a pencil point or similar. I wasn't convinced it would work, but used it on my Sigma 33 and it was the bees knees. Youcan buy it by post or Salford House Windows in Otford near Sevenoaks will help, talk to Patrick, tel number in the back of PBO

23-08-05, 06:55
Use Arboseal GZ. It comes in a long reel about a foot across which costs about 4 and is used by glaziers to seal double glazing. One reel would be enough for several boats and it is easy to apply and would last you a lifetime. The surplus which is squeezed out when screwing on windows is easily trimmed off with a Stanley knife leaving no sticky mess. 10mm x 2.5mm section would be best, although my local double glaziers only stock 10mm x 3mm which means a bit more surplus to trim off. Even the trimmings can be reused for deck fittings etc. but not if exposed to petrol eg filler bedding for fuel inlet. It handles like plasticene. I took technical advice from by email them and this was the grade of their product they recommended. They replied the same day.

The makers, Adshead Ratcliffe, ( http://www.arbo.co.uk/index2.htm ). cannot supply you direct but just go to your local double glazing company, they will. /forums/images/graemlins/smile.gif