window recondotioning

Nov 12, 2014
90
Jeanneau 42 Northport
Hello gang,

So I've tackled my through hull project and am on to the next one of 100,000,000. LoL, got to love old boats, they know how to keep a sailor busy. Good thing i love this tub....

Ok back to the topic, I need to re-bed all of my sky lights. There are 4 and are about 8' x 2'.
All show some signs of leaking from the interior, some worse then others. The boat is a 1989 Jeanneau and the existing sealant looks original. I was lucky enough to find some of the original nuts and bolts the manufacture used to clamp the windows down in the boat, thank your previous owner. See attached pictures.

Here are my questions...
1. Where might I be able to find more of these nifty nuts and bolts if I run out?
2. What type of sealant should I bed the windows in? It is currently a black sealant.
3. What are some helpful tips when removing the existing? I'd hate to damage the original plastic windows or the metal framing.
4. What type of plastic are these windows most likely? Just wondering because they have some signs of sun damage, but I rather not replace them because it doesn't seem very serious.

Cheers!
 

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Ted

.
Jan 26, 2005
1,254
C&C 110 Bay Shore, Long Island, NY
The nuts you have are commonly called "sex nuts". Really. Also called barrel nuts and they can be purchased from Mcmaster.com
You should use cast acrylic "Plexiglass" and seal them to the boat with Dow 795.
 
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Apr 13, 2007
142
Catalina 27 TR Lorain, Ohio
Those look like Barrel nuts. bargainboatparts.com has those in stainless. What you have seem to be aluminum. Do a web search for Aluminum Barrel nuts and you will probably find them. There are other names for them as well. Every forum I've seen seams to like Dow 795 for the bedding of windows. Be sure not to squeeze too much out. Leave a spacer so you have @ 1/8 inch of sealant and the fiberglass. Several discussion on this recently.
 
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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
[QUOTE="...The nuts you have are commonly called "sex nuts". Really. Also called barrel nuts ....[/QUOTE]

I think they are only called "Sex Nuts" when you use them with the metal "stud"- like in a note book or such. Otherwise, if the shoe fits....
 
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Jun 8, 2004
10,024
-na -NA Anywhere USA
Once you have an opening in the seal to insert fishing line, you can use it like a saw cutting the rest of sealant. Dow 795 is the standard sealant to use and Joetech is correct about using a spacer between the fiberglass lip and the window pane
 
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Jul 20, 2005
2,422
Whitby 55 Kemah, Tx
I used the down 795 once and it was crap. When water got in there, it would turn the water black before it dripped into the cabin. I now use black Boat Life Life Seal. Note, not Life Caulk, but Life Seal. That stuff is great. All my hatches and my big sky light are sealed with it and nothing holding them in but the life seal. I've sailed a rough 6,000 miles on them and still no leaking. Sure, it costs more, but well worth it.
 
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Jul 20, 2005
2,422
Whitby 55 Kemah, Tx
As for cleaning the old stuff off, I use a solid scraper to get the big stuff off then use a round disk of sandpaper on the drill. Not the flat stuff you normally see, but a 1 inch thick wheel of sandpaper strips. Works great. Just make sure to tape everything up, especially on the inside. Once that black stuff dries, it's hard to get off stuff.
 
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Nov 12, 2014
90
Jeanneau 42 Northport
Ehhhh , I have no problem spending the extra money for the boat life if what you say is true. Thanks for the heads up.

So, last night I removed all the sex bolts on one of the sky lights. I was unimpressed by the use of thin aluminum scews.. But after looking more closely it seems like only the thin screws were leaking and not the bead around the window. This actually seems to be the case for all the sky lights. With that being said I'd like to simply replace all the sex bolts with slightly thicker hardware, re-seal each sex bolt, then add an additional application of sealent along the outer beads.

What do guys think?

Ohh and See attached pictures
 

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Nov 9, 2012
2,500
Oday 192 Lake Nockamixon
For sake of argument, what would beefier fasteners do for you? On most fixed portlights, they seem to be mainly to hold the plexi in place while the sealant cures, or in your case, to also hold the trim ring in place. Keep in mind that the fasteners may seem small diameter compared to the holes in the plexi because the holes in plexi are deliberately larger to allow for the dissimilar thermal expansion rate of the plexi compared to the fiberglass of the house/deck etc. So, based on your description of leaking at the fasteners, I think I might try to seal each fastener well, and be prepared to redo the sealing in a few years, as the seal to the fasteners may fail due to the thermal expansion.

Also, I think I've read of some who have sealed aluminum trim rings with MaineSail's Bed-it Butyl tape, and I think Maine has said this would work well. You might want to do some searches over the past 2 years to see if you can find what I vaguely remember.

http://www.pbase.com/mainecruising/butyl_tape
 
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Nov 12, 2014
90
Jeanneau 42 Northport
I was thinking larger sex bolts originally, but you bring up a great point.

I will use the same diameter with butyl tape.

This should allow for a better seal.

I plan too ...
Purchase new sex bolts
Counter sink the aluminium framing
Apply butyl tape to the bolt head and shaft
Then reinstall all screws

Hoping to get 4 years out of this... wishful thinking maybe.

Now can I add aditionall sealent around the existing bead? What prep might I need to do?
 
Nov 9, 2012
2,500
Oday 192 Lake Nockamixon
If you mean an existing bead of sealant around the portlight, I found when I replaced my surface mount portlights, that the sealant was exceptionally well sealed. My leaking problem was a result of spider cracking in the gel coat at fastener holes, radiating out underneath the sealant to open air gelcoat. This allowed rain to move into the crack, under the sealant through the crack, and into the cabin. Further to this, I did not see the spider crack issue until I had removed the portlight and sealant. It protruded beyond the sealant bead maybe 1/32". My understanding from MaineSail is that a pilot hole drilled in fiberglass, WITHOUT a subsequent countersink, will allow for stress risers and spider cracking.

My guess is that you found your leak at the sex bolts, not under the sealant. Based on my experience, your sealant might be just fine, and sealing the fasteners with butyl tape might just solve the issue. Based on my understanding of silicone contamination, adding new sealant over existing sealant will probably fail, because nothing sticks to silicone, including silicone. If you later determine you have a leak through the sealant itself, I think the only proper way to fix that is to tear it all apart, mechanically remove contaminated gel coat, and reseal.
 
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Nov 12, 2014
90
Jeanneau 42 Northport
Thank you Brian, and everyone else here on this thread. I appreciate the helpful tips and incite.

I will go ahead with resealing just the bolts this year. I think this will do the trick and save a lot of time. Butly tape is on order!!

This old boat has plenty of other projects I most tend to so saving time is an added bonus.

Cheers!
 
Nov 12, 2014
90
Jeanneau 42 Northport
Progress Update.

Yesterday I removed the sex bolts from all the window sky lights and found three lights have pulled away from the sealant. Because of this I've decided to go ahead with completely removing all of the deck lights, re-bed and install new sex bolts :banghead:. It's a bigger job but I want to do it right the first time.

Some questions...
  • Can I re-bed the entire windows in butly tape or just the screws and the aluminum trim?
  • I herd Sika makes a nice product for sealants, anyone familiar with it?
Cheers,
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Yes, Sika makes excellent products; however, very expensive. Also need multiple primers. I have read that the sealant is not nearly as effective if the primers are not used .
See their "Sikaflex Marine Handbook" online.
The primary sealant is Sikaflex polyurethane (295iUV)
Also need Sikaflex primer on fiberglass (206G+P)
Sikaflex primer or acrylic lens (209)
Also need the activator (205)
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Alternatives: Dow 795UV, Boat Life Seal, or Butyl tape.
I recently did the deck sky light on my Beneteau; used the same material that Beneteau use at factory. Its called
EMFI Mastic PB along with 3M591 primer. Note that EMFI is a European company that was acquired by 3M. I purchased the sealant and primer directly from Beneteau USA.