Replacing windows

[Troppo]

I'm replacing Windchaser's windows. They have been a bit like me, a bit crazed. This summer, I put reflective foil on the inside of the windows as so much heat was coming through with the sun, I wanted to keep it out. However, both the biggest windows developed cracks right down the middle and required masking tape as a temp sealant. I am thinking that with expansion in the sun, they couldn't hold together any longer. Also, I knew the windows were not sealing and with rain leaked in various and mysterious places.

Windows need replacing

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Before coming up on the slip, I removed the windows on one side and took them to the plastic place to inquire about replacements. There was only clear or smokey to choose from in acrylic (perspex) so went for smokey. Was quite cheap, $160 and only took a couple of days. I had covered the windows openings on Windchaser using duct tape and plastic sheet. Had a shower of rain so I was pleased I had done so. Then I realised I had water in the bilge and it could only have come via those windows, so I don't think the duct tape was much good. Plus, it left sticky stuff on the boat which happily came off easily with metho.

Plastic and duct tape, water still got in but kept the swallows out.

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In various places, once I had removed the windows I could see dirt where it was not sealed and water would have been getting through. Used a chisel as a scraper to remove the sealant.

Dirt under window showing where it was leaking.

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[Troppo]

Started repairing the window surrounds. In several places, the layers which showed in the window-cutout were coming apart. Water seeping past the window seals would have been going down these cracks and mysteriously appearing in other places lower down.

Crack between layers in window cut-out

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I was surprised when I eventually discovered that the middle layer in the window-cutout is old perspex. Somehow, the original windows were set in-between the inner lining and outer shell, held in place with some small screws on the inside. When the windows needed replacing, they were simply cut out leaving the edges still between the layers. The screws inside were simply painted over.

Epoxied the layers together. Filled the screw holes with epoxy and filler powder. Some of the surrounds of the windows were pitted. Using epoxy and a paint scraper with flexible blade which I used as a squeegee, I squeezed epoxy across the surface and forced epoxy into the holes.

Repairs underway.

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After much sanding, I painted two coats of two pack primer, used a roller. I am doing the surrounds of the windows, not the whole cabin roof.

Sanded and primed

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After more sanding the next day, gave a coat of two pack top coat.

Top coat

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In the picture you can see a dollop of paint that should not be there. I had just started painting, in fact just touched the roller to the surface when something or other happened and I had to rush down the ladder to fix it. When I came back up, the darn run of paint had started to harden so I just left it. The afternoon sun had warmed up more than I wanted and the paint was starting to skin over in the tray so I had to work quickly.

I'll post more when I have done more.

troppo

[Phillip]

Troppo,
Make sure you put a washer between your window and the fiberglass.

This will ensure that you still have sealant between the window and the fiberglass.

That was the leak problem with your previous fixing.

[frank]

When drilling holes in Perspex you should leave a bit of clearance around any holding/fixing screws etc to allow for expansion on hot weather days otherwise you'll end up with cracks.

[rob.lovelace]

I put my windows on twice, like every job I've done on sundowner I get it done then so one tells me the right way to do it. I didn't put washers on like Phil has said and I didn't use any etching primer on the polycarbonate, apparently the sika won't seal properly without it. I used those plastic washers that come with the button caps for covering screw heads as they are a couple of mm this and have flex. ( shipwrights tip ) after all that by the time I got to the last window I could do it reasonably well without much mess. Needless to say I still have one leak right above my head when I'm in my bunk.

[lockie]

If you need a quick temporary fix, Gaffer tape will keep water out for months.

Graeme

[Troppo]

With the boat almost ready for the windows, I worked on preparing the cut acrylic sections. The system I am using is a no-screws approach similar to this article http://www.thecoastalpassage.com/windows.html. However, I am using different products as I found the products in the article difficult to economically procure and was not sure about some of the process.

Set a pencil on a piece of wood the exact distance the windows overlapped the boat. Ran a line around the window.

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With very little pressure, marked the paper along the line and pulled it off.

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Sanded the exposed section using 180 grit until it was evenly abraded. Wiped with metho and a clean cloth. Surface was now a uniform dull black. I added masking tape around the edges and cut to shape.

At the boat, I stuck onto the windows a specialist two-sided tape. It is not only super sticky but is used with silicon sealant/adhesives for windows and comes in various thicknesses. Got it from tapesonline.com.au http://www.tapesonline.com.au/double-sided-tapes/black-structural-tape-3-2mm-thickness.html

I got 3.2 mm as that is the thickness of sealant recommended for acrylic windows of the size on Windchaser. Was not sure how much tape to use but wanted enough to hold securely in place for the days it takes the sealant to cure.

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Masking up the boat is very important. I did not realise just how black and sticky the sealant was and proper masking is critical to stop it getting where it shouldn't.

On the boat, using my pencil-on-stick, I made some guide marks on the window surrounds, taped it up, used the pencil to mark the lines and then trimmed the tape. Sanded the exposed section to make for strong holding by the sealant.

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I made a mistake as it would have been better to have added maybe 5 mm to the measure so there was space between where the window touched the boat and the tape. As it was, the window sat against the boat inside the space marked by the masking tape but it was snug. This meant when I was actually placing the window on the boat, it was not perfect to the mm which meant some of the masking tape was under the window a little bit.

Using Fixtech Fixsil FS 200 http://www.nauticexpo.com/prod/fixtech-marine-solutions/silicone-adhesive-uv-resistant-37358-284106.html I followed the directions. Squeezed a bead around the window and NOT over the double-sided tape. Using a paint scraper, spread the sealant in a thin layer over the acrylic sheet. Then put higher beads all the way around. Carefully took the paper off the double-sided tape and even more carefully placed the window in position. In fact, before putting any sealant on the window or activating the double-sided tape, I practiced placing the window where it should go.

The window immediately and solidly stuck in place. I then squeezed sealant around the window to fill up the remaining gap. I had disposable gloves on, used my finger to smooth the sealant. Immediately pulled off the masking tape leaving a nice edge.

Problems: I ran out of sealant on the third window. Needed to order in more so be days before the windows are finished. The sealant is on the masking tape so when it is pulled off, try to avoid touching the sealant and get that waste masking tape right out of the way. I got sealant on my gloves, especially since I used my finger for smoothing so I went through a few sets. Be careful of the smallest spot of sealant on your fingers as anything you touch will be marked in black. With the masking tape mask on the boat too confining to the windows themselves, I found I was pulling off too much sealant when I was pulling off the tape. I needed the have the masking tape a little further away.

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You can see a smeared patch of sealant under the left hand window. Masking tape mask was not done well at that point and touching the sealant to try and fix it was a no-no.

A shower of un-forecast rain came across the river, missed me but the winds blew strongly for a minute. Dust stuck to the edge of sealant I had just laid. The instructions for the sealant say to protect from sun for maybe 5 days, which I thought was odd until I found out the reason. In the sun, the windows will be doing their maximum expansion and this is not good with the sealant not fully cured.

Notice in the right of the pic, the old boat? It is a 100+ year old river boat that was smashed and sank in the cyclone. It has been floated to the slip where the almost brand-new Yanmar will be removed along with a few other bits and pieces before dumping the rest.

So, in summary, the special sealant and tape are designed to hold the acrylic windows in place giving the right thickness of sealant so the windows can shrink and expand without breaking the seal. It took me a bit with getting it all together, hopefully it will be long-lasting.

troppo

[woodsy]

That's really informative Troppo.
I read the article in 'The Coastal Passage' some time ago & wondered about relying on just adhesive to keep the acrylic in place. I look forward to your 'how its going so far' report.

[Brouhaha]

Hi all,

I've done this very procedure on my Investigator 563.

3M VHB tape, exhaust paint on edges of perspex. I did use Corning 791 silicone as its expansion rate is well suited to Perspex's expansion rate.
nearly 2 years on now and the I563 windows don't leak a drop... the I563's now on a mooring so always exposed to the elements and as mentioned it's a fantastic procedure.

Cheers, Pete