Job Report: Rebedding wraparound windows

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chicagocat
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Job Report: Rebedding wraparound windows

by chicagocat » Mon May 20, 2013 2:21 pm

OK, so I thought ahead enough to document my adventures this past weekend. The wraparound acrylic windows were developing a couple slow leaks. Instead of (once again) siliconing the edges, I decided to rebed them. It's a messy and nasty job, but not complex. The starboard 3 windows took 2 people 4 hours, including lunch.

First, you're going to want to replace the nylon washers, which are probably deteriorating. I found exact replacements at Amazon.
Here's the link:

http://www.amazon.com/gp/product/B000Q9 ... UTF8&psc=1

About $9 for a pack of 100.

Then you're going to need a sh*t ton of Sikaflex. It has to go on very thick. You'll use 2-3 tubes per window. The best price I could find was also Amazon at $17 a tube. You want Sikaflex 295 UV in Black. It's specially made for acrylic and polycarbonate. You need black, because otherwise you'll see it through the windows.

Next, remove the screws from the windows and slowly use knives, paint scalers, etc. to loosen all edges from the old Sikaflex. This is the hardest part of the job and will take at least 20 minutes per window. If you try to pull a window off without cutting the old Sikaflex, you can easily crack it. My first pic shows a paint scraper being used to loosen the old sikaflex.
image-7.jpeg
scraper to unseat old sikaflex
image-7.jpeg (92.22 KiB) Viewed 10359 times
Eventually you'll be able to get the window off. Then you're left with my 2nd pic, a mess of old sikaflex. The sikaflex has button-size standoffs embedded in it to hold the window a fraction of an inch off the fiberglass. You need to dig those out to reuse later.
image-5.jpeg
Old Sikaflex
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Then scrape off all the old sikaflex. See picture 3. Also, scrape the sikaflex off the windows and wash them with soap and water and let them dry.
image-1.jpeg
scraped off frame
image-1.jpeg (57.09 KiB) Viewed 10361 times
Next, apply the new Sikaflex very liberally. Then use a putty knife to "butter" it so that no white fiberglass can be seen. It should be maybe 1/4" thick. Make sure to put the standoffs in the sikaflex to hold the window slightly off the fiberglass.

Then position the old window and move it slightly until you've found the exact spot where the old screw holes are.

Next, slowly tighten the screws with the new nylon washers using a round-robin pattern (don't just tighten them in order). The sikaflex will squirt of the sides of the window, both inside and outside the boat. Use dry paper towel (have at least a dozen rolls ready) to wipe it up. You can use solvent on the plastic window frame, but don't use solvent on the windows themselves, as it will cause hazing. Just use dry paper towel and keep working at it.

Any other ideas or suggestions, please let me know.
PDQ 36052 - 1996 LRC - "Anne Z" - Chicago
and 2001 PDQ 36 Classic (Tall Rig)- "Cat Tales" - Punta Gorda, FL

amytom
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Re: Job Report: Rebedding wraparound windows

by amytom » Wed May 22, 2013 5:33 pm

For cutting the windows loose I used a windsheild remoaval tool from Harbor Freight. It's basically a sharp edge on a handle with another handle atached with a cable. Two hands in use, one pulling while the other guides the blade.

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Re: Job Report: Rebedding wraparound windows

by NautiBits » Mon Sep 02, 2013 10:50 pm

Hi Gents,

It has been a while since you posted this. Is there anything different you might add to the successful completion of this job? I will probably do the port side before I attempt the starboard side. So, a case of sika 295 should do me for that. If I'm careful, I should have leftovers for the starboard side. How much primer and cleaner? Will one can of each do both sides of the boat? I know about the 209 primer(that it is required). Do you just swab it on the cleaned fiberglass like you would on pvc pipe(Sounds messy)? Besides the physical cleaning of the old adhesive, what else should be done to ensure a good job?

Is the repair standing the test of time?

Joe Mc
Joe & Deb
s/v Cat's Meow
2000 Classic 36086

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Re: Job Report: Rebedding wraparound windows

by amytom » Mon Sep 02, 2013 11:02 pm

Biggest piece of advice is cover everything you don't want black glue spilled on. A few inches of tape is not enough, mask it off as if you we're going to spray paint.

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Re: Job Report: Rebedding wraparound windows

by NautiBits » Tue Sep 03, 2013 6:42 am

Thanks Tom.
Joe & Deb

s/v Cat's Meow

2000 Classic 36086

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chicagocat
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Re: Job Report: Rebedding wraparound windows

by chicagocat » Tue Sep 03, 2013 4:48 pm

I agree with Tom on the masking.

That said, if you do get the Sikaflex on something smooth ( like the smooth parts of the deck or the inside floor), it can actually be easier to remove once it's dried. It becomes a rubbery substance that can be pulled off in a single piece. Very different from something like 4200. But if it gets on the nonskid, may the Flying Spaghetti Monster help you, because it ain't good.

My job is generally doing well, but one window leaks and needs to be rebedded. In retrospect, I can see that I didn't get the Sikaflex on there thick enough for that window. You really need to butter that stuff on. If you do it right it will be 1/2 an inch thick with absolutely no spaces unbuttered.
PDQ 36052 - 1996 LRC - "Anne Z" - Chicago

and 2001 PDQ 36 Classic (Tall Rig)- "Cat Tales" - Punta Gorda, FL

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Re: Job Report: Rebedding wraparound windows

by NautiBits » Tue Sep 03, 2013 9:12 pm

Thanks B,

I'll guard the non-skid.

1/2 inch thick? Wow!

Is there a spacer around every screw? Could there be spacers not on a screw?


Joe Mc
Joe & Deb

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2000 Classic 36086

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Re: Job Report: Rebedding wraparound windows

by chicagocat » Wed Sep 04, 2013 10:59 am

On mine there were a couple spacers near every screw, but also some that seemed to be almost randomly placed.
PDQ 36052 - 1996 LRC - "Anne Z" - Chicago

and 2001 PDQ 36 Classic (Tall Rig)- "Cat Tales" - Punta Gorda, FL

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Re: Job Report: Rebedding wraparound windows

by James Power » Wed Sep 04, 2013 1:54 pm

Hey Guys,

At the factory we would put a spacer on both sides of every screw, and then a few random ones as needed to ensure that the goop was a consistent thickness.

A can of cleaner and primer should be enough to do the job.The cleaner is us used first to prep the surfaces, then a consistent coat of primer is applied to both surfaces to ensure adhesion. As mentioned, its a messy job. Have ready lots of rags, acitone, gloves, application sticks ... If working in direct sunlight, use a tarp to shade the work area so the sealant doesn't skin over too quickly.

Hope this helps
James

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Re: Job Report: Rebedding wraparound windows

by NautiBits » Wed Sep 04, 2013 10:04 pm

Thanks for the details.

Are the screw holes sealed by the Sika 295 or are they sealed with something else?
Joe & Deb

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2000 Classic 36086

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Re: Job Report: Rebedding wraparound windows

by NautiBits » Fri Sep 13, 2013 10:49 pm

The reason I ask that last question regarding the sealing of the screws is one salon window was replaced just prior to purchase 3 months ago. It leaks like a sieve. It leaks around the screws and the adhesive on the perimeter. I'm assuming a poor job was done. I'd like to do a better job than that.

So, any knowledge on those screws?
Joe & Deb

s/v Cat's Meow

2000 Classic 36086

Bob
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Re: Job Report: Rebedding wraparound windows

by Bob » Mon Sep 16, 2013 6:05 pm

We replaced all of ours last year using Sikaflex 295UV. Used the correct cleaners and primers for the respective surfaces, used window spacers to ensure even squeeze with the new bedding. We heated the plexi to form it and put loads of Sika- 3 complete rings plus zig- zag. We got an even squeeze all around and all was good. A year later after a ~3000 miles we developed two leaks. No way was I going through that process again. I ended up taping off and forming a fillet of black silicone around the tops and have no leaks. I think between the boat flexing and sunlight both causing movement there is no getting away from the occasional leaks. I'm getting ready to move the boat from Maine to the Chesapeake so we will see if the silicone keeps everything dry.
Bob Johnson
Hull 36045
Peace

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