UV Window Adhesive Protection

Ben

The reason it took us so long, one window per day, was that we did not want to remove all the windows and inevitably need to leave the boat open to the elements and stray, covetous hands. We did all the work on our swing mooring - it would be easier and quicker if the boat was on land as it would then be easier to apply pressure to the window as it set off, you might be able to apply covers and streying hands should not be an issue.

We therefore chose our weather took out one window at a time, cleaned up the surface of the cabin roof that would take the new window, applied the adhesive to the sanded and painted surface, installed the battens, added the water weights, cleaned up as much as possible the edges, inside and out, and then left overnight. The next day we then filled the edges where necessary and started on the next window. We had windows to replace on both sides and we have a top row of windows and windows parallel at a lower level, just above the deck. We did opposite windows in turn, leaving the 'first' window to cure off. Basically we did one window on one side and the next on the other. We had 4 x 20l bottles so could have weights on 2 windows at a time. After 2 days we took the first lot of water off, ready for the window we were working on. We left the battens on for 3 or 4 days, so you need lots of battens. Finally we filled the screw holes for the battens, 4 holes per window. Ours is a foam construction so the panel thickness was large and the screws for the battens did not go 'right through'. The screws were applied through there adhesive and the holes were easy to cover. We discovered this was roughly how the windows were originally applied as when we cleaned up the old adhesive we found the old screw holes.

A good scraper to clean up old adhesive is easily made from scrap acrylic (we had a lot!) Simple grind a sharp edge at about 45 degrees. The acrylic scraper will not then damage to gelcoat. You need a good few, the edge blunts. Or you need to keep them sharp. A good sander is also invaluable, to rough up the edge of the new acrylic and to clean off the old adhesive. So lots of sanding discs and lots of masking tape.

You weill need AC for the sander - or a good supply of batteries.

Cure time is quite long and we had to keep the sun off, easy and we had 2 x 20 litre water bottles keeping the adhesive cool plus a cover.

All our windows are large with at least one dimension 1m and the other dimension around 750mm. With a 100mm overlap we used a lot of adhesive.

We did not use it, but geared up in case, but we had 2 of those sucker things glaziers use to carry glass, ours had 3 suckers on each device. We arranged we could use them on the interior - with ropes and a frame to act as an internal means of applying pressure. However the water bottles were sufficient so did not use it. These would be useful if your windows are vertical as then water would not work. We use sucker devices when we clean the hull from the dinghy - they are dual purpose.

The biggest No No is don't use turps to clean up - its great BUT it will wick under or though the adhesive and reduce the bond. From memory ours was soapy water. Its not as good as turps, to clean, but these adhesives use water to set off so it does no harm. Turps is good when you get adhesive somewhere on the superstructure that was not intended (but keep it off the 'working' surfaces).

As you appreciate preparation is the key. You will be a bit apprehensive when you do the first one - but its actually quite easy and at the end of the day immensely satisfying.

As mentioned our windows are quite dark acrylic and you have no idea how well the adhesive has bonded, spread and set between acrylic and superstructure. When we had finished we took a hose to our work and checked for no leakage.

If you want to see what our windows look like google Lightwave Yachts, ours is a basic and early 38', not the fancy Forte.

Jonathan
 
Ah ha! Thank you... I have a couple of the window suckers still from when I installed my window in the side of my van. a frame for the inside and some straps might be the answer to keeping everything in place (windows are indeed vertical... apart from the 45 degree ones on the front of the pilot house. I was trying to work out how I was going to do the backfill whilst retaining pressure eon the window... that's the answer.

I think my plan is to mask the area around the windows (and the windows themselves) so I can avoid using anything that might compromise the integrity of the bond.

Fortunately, I have a couple of smaller ones either side of the companionway... they'll be the first to be done so if anything goes wrong then the clean up and possible replacement of acrylic won't be too disappointing.

I'll be working in the marina where I will (once this whole coronavirus thing comes to an end) be living. I do need to take the boat out of the water but I suspect I'll be too busy sorting the myriad of other issues I need to get onto (including the intake seacock for the lavac which I suspect was the reason for yesterday's disappointment). I guess, in terms of time, it's just going to be a case of finding out... I also don't want to be in a situation where I'm missing windows for any length of time. The marina is secure and there are plenty of liveaboards to keep an eye out but it's more a case of not wanting to live, in effect, outside till the jobs done.

I will do my best to get some photos of the process and post them up. I am notoriously bad at this though as I tend to get my blinkers on once I start a job and usually forget to document things. My partner is, however, much better so I'll ask her to get some snaps... plus... that way she will have a documented account of my stupidity which can be resurrected should things go wrong later.
 
I replaced my acrylic in windows, portlights and deck hatches this year, I bought the acrylic and all the fixings, spacers etc from Hadlow Marine in Kent, their website is good with lots of technical info. which gave me confidence in their technical advice and their choice of products.
The windows were framed but needed bending to the curve of the coachroof so rubber spacers were supplied to use with the sealant to stop it squeezing out round the bend, the sealant was Arbosil 1086. The Lewmar hatch acrylic does not have any mechanical fixing, it is entirely dependent on adhesive. The acrylic was bedded on EHB 1203 high bond double sided tape, after placing the panels I loaded each hatch with a load of magazines (must have been over 50kgs on each.) for three days as recommended by 3M. then they were pointed with Arbosil 1081. A lot of masking tape was used to keep things clean. The window frame to coachroof joint was also bedded on tape, this time it was Scapa 3507/12 but this is a sealant tape with limited adhesive qualities as the frames are mechanically fixed.
Scrapers for removing old and surplus new sealant were supplied made from waste scraps of acrylic, very effective.
Detak is a liquid that softens old sealants to aid removal.
 
Sikaflex 295UV with the 206D primer on the Acryllic, and Multimarine primer on the GRP. We used small self-adhesive rubber blocks to set the minimum thickness. been on 2 years now, not a single drip. We routed our own windows from 10mm perspex and made up moulds and got a locl aplastics firm to heat form them.
 
Hi everyone,

I'm new to this forum and also new to boat ownership having just purchased myself a Trident Voyager 35 to live aboard and - once I've done enough work to it to satisfy myself - go cruising in. My most pressing issue at present relates to the replacement of some irritatingly leaky windows. My plan is to replace the current aluminium framed windows with some surface mounted acrylic. I've been looking at Sika's range and I'm comfortable with everything apart from one issue... UV protection. Whilst it appears that the 295UV is (as the name suggests) UV resistant, the primers aren't. I know Sika produce a UV tape but that seems like a fairly untidy solution. My windows aren't neat squares and I don't want to have to start faffing about trying to make tapes look tidy. What I'm hoping is that someone has some experience of this and might be able to recommend a UV resistant paint that will work on acrylic. I'd like to cut a neat border from the sticky protection film on the acrylic and then spray a UV protecting border. Is this a viable way forward?

Many thanks in advance for your knowledge... hope you're all keeping well in these crazy times...

Ben

Hi Ben,
What was your conclusion regarding UV Protection paint instead of the Sikaflex Strip...?

Any specific paint recommended...?

Yours,
Sandy
 
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