Replacing Dead lights

[suereal]

I've read through the site and Tech Wiki and wold still appreciate some insight from those saltier than I. The dead lights on Seaclusion '87 C34 hull # 364 need to be replaced. Don Casey makes this sound like a straight forward DIY. My Questions are: Does anyone know the thickness of the plexiglass? (I'd measure myself but I'm in the US and the boat's in MX). I assume that it's 1/4 inch but verification would be awesome! Has anyone cut their own plexiglass and is it straight forward? Also, has anyone used 3M VHB 5952 tape to attach the plexi? It would be a screwless  installation. Thanks.

[Noah]

1/4 is standard. The standard have a bevel on inside edge so I wouldn't cut myself. I had local plastic vendor cut. Search Forum for "fixed portlights". Should find my posts and others. I used Dow 795 not VHB.
https://c34.org/bbs/index.php/topic,10228.msg78760.html#msg78760

[scgunner]

I used 1/4' plexi as well when I replaced mine. I ordered it from an on line vendor which worked out fine. I cut and beveled it myself, it's fairly easy to work with. I went with 795 as well since your still going to have to glaze if you go with tape. Also, I think the tape install could get a little dicey with those large pieces.

[KWKloeber]

Thanks:

The CTY drawing showing the replacement technique is on the wiki, under the appropriate topic heading. Use this link to get there.
https://c34.org/wiki/index.php?title=Catalina_34

Ron also has an article on the wiki.

If you always take a quick gander at the wiki for info it makes the folks feel better who spent all the time posting the content there.

See also
https://c34.org/bbs/index.php/topic,6511.0.html

Cheers,
your welcome

[suereal]

Thanks for the help all it'll really come in handy. I can't wait to be able to return to her and get some work done. KW, I actually did take a look at the WIKI  and found the link: https://c34.org/wiki/index.php?title=Catalina_34 to be missing. Plus, I'd not heard of anyone using the 3M tape instead of 795 and was wondering why. This site is such a great source of info it's always my first resource. Thanks again.

[Noah]

One last comment: I contemplated using VHB. My thoughts were:
1. Go with Catalina Yachts' recommended procedure.
2. VHB would have worked on windows that weren't as large or vertical
3. Still would need to seal around anyway.
Also, unlike "standard hardware store silicone", Dow 795 can be touched-up/applied over itself once cured. Important if you find dips/voids/popped bubbles, after cleaned-up/cured and trimmed with razor blade.

[ewengstrom]

I did this job this past weekend. I used 1/4" Acrylite (here's a link to the product I used https://www.acrylite.co/extruded-grey-7c026-gt.html)
I used a band saw to cut it because it didn't melt the plastic as is cut, and did the final shaping with a belt sander.
Beveling was done with a chamfer bit on a router but when I was actually fitting the windows I ended up doing some minor adjusting and used the belt sander again to both adjust the size and bevel the back edge. I found this to work pretty well as long as you work quickly to prevent heat build up.
I did use the 1" 3M 5952 VHB bonding method. A 15' roll will do both windows on one side with absolutely NOTHING to spare.
To deal with test fitting the new lights I used masking tape to hold the window and get it aligned correctly, then when I was happy with the fit I cut the masking tape leaving four strips on the new window and four on the frame, then pull the backing off of the 3M tape, realign everything using the masking tape and adhere the window to the frame.
A note of caution, a friend of mine used this method to replace the deadlights on his C27 and had issues with the plexi not adhering right away, I addressed this by carefully wiping all the surfaces where tape would be applied with lens wipes (for glasses). They are safe for polycarbonates and acrylics and the VHG grabbed instantly. (I don't believe he wiped anything down)
After the glass is installed and adhered I taped the frame off around the plexiglass and used Dow 975 to glaze the windows.
This method isn't as hard or awkward as it sounds. I didn't have to deal with a large amount of black caulk squeezing out and if you're careful, aligning the windows isn't too difficult either.
The hardest part was cutting the old windows out and cleaning up the old caulk. It took me all day Saturday to do the port side and all day Sunday for the Starboard side....so plan accordingly.
A big plus for this method is now I don't have to deal with the screws, I found that a few were stripped so I'd have had to repair and/or re-drill new holes, I didn't have to do either with this installation.
A good description of the method can be found on Youtube, here's the link. https://www.youtube.com/watch?v=MQyjxVUskd8&t=69s
I haven't figured out how to post pictures yet, the darn things are just too big, but I'm quite happy with the results and can move on to other projects now.
Hope this helps.

[Jon W]

Andy on Boatworks Today is a great content for all sorts of fiberglass repairs as well.

[Stu Jackson]

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I haven't figured out how to post pictures yet, the darn things are just too big, ...............

Thanks for the helpful post.

This may help with your pictures:

Posting and RESIZING Photos 101  http://c34.org/bbs/index.php/topic,3701.0.html

[suereal]

Thanks for the feedback. I'd seen Andy from Boatworks Today and that looked to be a very clean install. I have also read of others who have used the 3M tape say that it doesn't stay stuck in hot, humid environments. If that's true it's a definite drawback. Noah, your instal with pictures is most helpful. As I said, the boat is in Mexico and I'm in the States. Accessing parts and materials in Mexico, San Carlos, is a crap shoot. So I'll like to get as much material and as many supplies while I'm here. I have several projects waiting for me when I get back to Seaclusion so I may be reaching out again. Thanks again for the ideas.

[scgunner]

Sue,

Whichever way you go you may want to consider using the screws on the final install. While screwless would provide a cleaner look the factory must have had a good reason for using screws.

[Ron Hill]

Guys : I would tend to agree with Kevin.  The C34 fixed side ports are not flat, but slightly curved.  When you take a piece of flat material and curve it that piece tends to want to be flat again. I believe that Catalina used the screws to take bending stress off of the silicone caulk.

A thought

[KWKloeber]

Kevin / Ron

CTY recommends NO screws.  i.e. conversely, there's no good reason to use what CTY doesn't recommend. 
It was one of the "good ideas" that in practicality failed.  The screws caused stress cracks at the holes, sometimes resulting in plexi failure at corners.

Dow 795 is WAY strong in adhesion.  Unlike typical household or marine sillycone, it's an adhesive more than a sealant.  Additionally, its property is like 50% elongation before surface adhesion failure. 

So CTY recommends, if one is determined not to follow that recommendation, to remove screws after cure and fill the holes with 795. 

Otherwise you need to overside the screw holes to minimize stress there.

Moral - follow the factory recommendation -- they have already reinvented this wheel.   

[scgunner]

Ken,

I think I'm missing something here, CTY recommends not putting screws in the side windows but put screws in the side windows. BTY, I've never had any stress crack problems with window screws on my boat and that's with two sets of windows. Is there anything else Catalina did that they don't recommend?

[Noah]

IMO, on the C34, unless you have a pretty elaborate jig to put pressure on the windows, you will need the screws—at least until the Dow 795 cures. Very important that the plexi screw holes are sized as clearance holes, not biting into plexi, and not tightened down super tight. Then I believe you won't have any cracking. You can remove and fill holes with 795 afterwards but that seems like it could be messy and look a bit funky? My screws remain. Will see...