fixed port installation

[gettinthere]

I have 4 salon portlights that need replacing. They are only fastened with adhesive.



I was skeptical of this installation but apparently it is very common. Drilling and fastening with screws invites leaks but with the proper adhesive, the attachment is fine.

So I'm looking for which adhesive works best, which "glass" works best, and most importantly, I'd like some tips on how to do this well.

Thnx

 

[Dave Groshong]

Dow 795

Dow/Corning 795 is the standard if you're using plexiglass, it is widely available, Sears etc....

 

[Ralph Johnstone]

You may find some useful information here ................

http://forums.sbo.sailboatowners.com/showthread.php?t=147745

................. as well as a search of previous topics related to fiixed ports, windows, acrylic, etc.

Many posts have been written on this subject.

 

[FastOlson]

Our model boat uses four long external lenses for its fixed ports. No framing. They are held in by screws around the perimeter, at least until the adhesive cures. I replaced all four of those lenses in 1995 with new Lexan.
Still no (zero, nada) leaks to this very day, and we get a LOT of rain here.

There are some "tricks" to the install, but it's not rocket science. I used BoatLife LifeSeal.

If you do a site search on that term, there's a boring story around here somewhere on how to do the actual install.... I was not very bright but did follow excellent advice from a shipwright friend who guided me on how to do it properly.

Arguing the 'other side' I do think that the framed ports like the Lewmar ones look a bit cooler.
But, they sometimes leak, and ours do not. When you have framed ports, you double up on the zones and interfaces for water to penetrate.......

Loren

 

[sailingseadragon]

Your fixed ports look very much like the ports in our Pearson... I our case the leaks were between the glass & gasket. See the link below to see how I stopped the leaks & some of the problems I encountered. Note: scroll 1/2 down to find the section the fixed ports.

http://www.sailingseadragon.com/Ports.htm

Good luck,
Garner

 

[gettinthere]

These are fixed portlights, not opening.

The aluminum frames are a 2 piece clamp, basically a trim ring clamped to the cabin side. The windows are glued to the inside of the aluminum frame. There are no screw fasteners touching the glass. There is only some type of adhesive caulk between the glass & the alum frame.

What I'm looking for, and can't find, is some guidance on how to neatly glue the windows to the aluminum trim

 

[Merlin Clark]

The plastics guy that is supposed to make my new fixed ports tomorrow told me to position the new plastic in place over the cut out (frame in your case) and mark the plastic skin, then cut and remove the outside edge that would be bedded, leaving the skin in the center. Mask the frame (cut out in my case) so the the sealant does not come in contact with it. Apply a heavy bead to the center of either the rim of the lens or the frame (this is from experience, I didn't do well when I tried 2 beads- trapped air in some spots).
He said to let the sealant cure the run a narrow sharp blade around to cut the bead where the sealant squeezed out and remove the masking and skin.
This is my plan. If it's wrong I hope someone will correct me?

 

[Allan12210]

This may be of some help also:

http://sbo.sailboatowners.com/index.php?option=com_mtree&task=viewlink&link_id=8052&Itemid=257

 

[gettinthere]

Allan, I read that and most of the window application did not make much sense to me.
Thanks

 

[BobM]

edges

S2 recommends that you abrade the plexiglass where the seal will be made / sealant will be. I saw an S2 where the owner did not and the windows had popped right off. There are no screws in the installation on S2's like mine, but my cars windshield is just glued in too right?

 

[gettinthere]

Abrading the lexan to get better bite makes sense, part of my plan.

I'm thinking I will hold the window up to the frame and pencil the outline of the frame from the outside. I'll cut out the protective paper at the pencil line. The remaining paper backing will provide an adhesive stop to keep it neat. What I'm not sure of is how to hold the window in place while the adhesive cures. I guess I'm looking at the Dow 795. How long will that stuff take to set?

 

[John Nantz]

Look at the seal like a rubber band

Sealant: First off, the Dow factory rep for our Northwest area helped me with my deadlight problems. He recommended that 995 be used (vice 795) as it has slightly better specs. Cost is only slightly more at the time (~ 15 years ago). 995 is designed for use on skyscraper windows. These windows are not held in with any metal fasteners and the only thing hold them in, against high wind loading, is the sealant.

Technique: The next main point is the glazing is NOT bedded. The instructions for both 995 AND 795 call for the sealant to be applied to the EDGE of the deadlight/window, etc. The specs call for a horizontal sealant length of 2 times the edge thickness. For 1/4 inch glass/plastic, then, the horizontal length is 1/2 inch.

Design: The sealant acts like a rubber band - it is supposed to stretch. Therefore, use a backer rod on the coach roof inside and when smoothing the outside, there should be a slight depression. It must not be flat or the sealant can be pulled off the edge of the glass. The cross section of the "rubber band" should have a thinner section in the middle than at each end, this way when there is a different coefficient of expansion the rubber band will stretch in the middle and the edges will stay attached. Without the backer rod and the depression on the outside (rub finger over the sealant right after it is applied) the sealant will not stretch there and will pull at the two ends. If the sealant doesn't adhere well it will separate from the edge.

That's the best way I can explain it. I've written this up in years past and maybe it's in the archives. Read the manufacturers application recommendations and this is what they say.

 

[BobM]

Holding in place during curing.

I am thinking I will make some sand bags out of some old pillow cases.

 

[Steve Dion]

If you are attaching acrylic to fiberglass and there is a curved surface, you can drill a few holes for screws. Be sure to use a plastic (pointed drill to prevent cracking) drill larger than the screw. When the sealant cures you can remove the screws and fill the holes with the caulking.

This is what they did on my HV'36 from the factory.

 

[gettinthere]

Sandbags? Gravity in my part of the world means that won't help with vertical sidelights.
As pictured and described, the windows are adhered to the inside of aluminum frames.