Author Topic: Rebedding Small Portlights  (Read 13856 times)

Dolce_Vita

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Rebedding Small Portlights
« on: May 04, 2012, 03:33:11 PM »
Well, I finally got around to putting this up on my website, even though it's been 2 years since I did it!

The small opening port in the head was leaking badly wheb we bought the boat, both through the
worn-out gasket and through the bedding.  I did a lot of research among sailors who had
performed successfull waterproof repairs and "borrowed" all their good ideas.  Full story at:

http://www.chessie.com/boat/projects.shtml#Port

It's now been two years and this repair has been rock-solid and leak-free.

The two key points that were essential were :
  1. Epoxy-fill the gap between the cabinhouse wall and the inner liner.
  2. Use Dow Corning 795 as the bedding.
@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

selene

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Re: Rebedding Small Portlights
« Reply #1 on: May 04, 2012, 05:24:19 PM »
Very nice!  Thank you for documenting this, it is most useful.

Libations Too

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Re: Rebedding Small Portlights
« Reply #2 on: November 15, 2012, 06:50:03 PM »
Hi Ed,

I just read your project description and found it quite informative and interesting. I also found a similar project summary on the Pearson 365/367 site by Sea Dragon http://www.sailingseadragon.com/Ports.htm. Your project focused on the opening port; Sea Dragon's project was for both the opening ports and for the fixed ports.

Both of you started by filling the gap between liner and cabin top. This makes sense to me. But you differed on your caulking approach. Sea Dragon used butyl tape and you used the Dow Corning 795 caulk, with which I am unfamiliar.

My question: Did you consider butyl tape? If yes, what advantage did you see with the 795 caulk?

Many thanks,
Richard
Richard

Dolce_Vita

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Re: Rebedding Small Portlights
« Reply #3 on: November 15, 2012, 11:32:59 PM »
Richard,

   At the time, I had not considered butyl tape, and had not done any research on it.  The Dow Corning 795 had been recommended by two very experienced DIY'er friends who had been using it for years with excellent results.   

Since then, I've done the research, and butyl tape looks quite interesting.  It has almost no adhesion strength, but has a fantastic elongation factor (something like 5x to 9x!) without rupturing.  I've come to the conclusion that in almost any bedding application that has its mechanical strength supplied by fasteners, and not by the bedding, butyl tape makes a lot of sense. Especially in places that tend to "work", like chainplate through-deck seals.

The one possible exception is where silicone has already been used on fiberglass/gelcoat.   Fiberglass has a tendency to absorb some of the oils from the silicone, making it difficult to get a seal with non-silicone bedding materials.  I do not know if this is a factor for butyl tape. 

On the last project I did (rebuilding the two deck hatches), they had  previously been bedded with silicone.  I considered butyl tape, but chickened out and stuck with the 795 because its a silicone and is compatible.
@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

Libations Too

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Re: Rebedding Small Portlights
« Reply #4 on: November 16, 2012, 12:07:08 PM »
Thanks Ed...really good info. My fixed port above the nav station needs some attention. I have been putting it off and simply covering the frame/glass/cabin joint with clear tape. It works for a season and then needs to be reapplied. It is not a big work effort to deal with the tape but it leaves me feeling guilty every time I put off a more comprehensive repair. I think this next spring I will take the plunge and make the authentic repair.
Richard

Dolce_Vita

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Re: Rebedding Small Portlights
« Reply #5 on: November 20, 2012, 11:43:27 AM »
Catalina direct has a window reseal kit that works for our P-323's large fixed portlights in the main cabin:

http://www.catalinadirect.com/index.cfm?fuseaction=product.display&product_ID=967&ParentCat=379

Note that they use Dow Corning 795 for the glass bedding, but switch to polysulfide for the frame-to-hull joint.
@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

selene

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Re: Rebedding Small Portlights
« Reply #6 on: December 02, 2012, 05:21:55 PM »
Hey Ed, 

The link you kindly provided to Catalina Direct is for a kit with 45 feet of molding/gasket.  I need to double-check, but my fixed ports seem to need about 6' per window (they seem slightly bigger than SeaDragon's P36) so I *think* the 25 foot kit http://www.catalinadirect.com/index.cfm?fuseaction=product.display&product_ID=1054  would be enough for all four?

I'm going to re-check my measurements next time I am on the boat, but just wondering if I missed something. The Catalina site does not mention any measurement except for linear feet, so it is not clear if that is the only difference between the kits.

 It has been raining so much recently that it would seem this is my next winter project....

Dolce_Vita

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Re: Rebedding Small Portlights
« Reply #7 on: December 03, 2012, 11:13:20 AM »
I think you're right.  The C-30 kit says it does all SIX fixed windows on the C-30,  while the C-22 kit says it's for four windows.

I checked my notes, and the fixed windows in the 323's main cabin are approx. 30" x 6"  and 28" x 5 1/4".  This would suggest that you need just over 6' for the bigger windows, and just under 6' for the smaller ones.  So you should be ok with the smaller kit, but it's close and you'd better measure exactly with a string to be sure.

My PO apparently ordered the bigger kit, because there's a bunch of leftover moulding & gasket.
@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

selene

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Re: Rebedding Small Portlights
« Reply #8 on: December 03, 2012, 12:15:50 PM »
Thanks Ed.