New Portlights for my 1973 Morgan

[Hudson Force]

I've been chasing leaks for 31 years among my 12 fixed portlights set in large rubber gaskets on my '73 Morgan and I've decided to apply 3/8" acrylic set over the apertures with 3M4991 tape and Dow 791.

The old 1/4" polycarbonate plates were clouded..


I removed the old portlights and cleaned the 1" thick fiberglass aperture for the ports....



Here's one of the four that I've completed. I have some pressure on this longer portlight to help secure a slight bend....


I'll post a full view when I finish this port side and turn around to work on the starboard.

[UNCIVILIZED]

What'd you use for adhesive? Ditto on prep solvents?

[Hudson Force]

I used the 3M VHB 4991 two-sided acrylic foam tape 1" wide and 90 mils thick. The recommended solvent prep, after thoroughly cleaning and sanding with 220 grit paper, was wiping with 50% isopropyl alcohol and drying. After pressing in place I ran a bead of Dow 791 black sealant around the edge.

"Pressing in place" is critical. There's no second chance adjustment opportunity.

[Delancey]

Looks real nice.

Sometimes, depending on what you are doing you can leave the release tape on the VHB except maybe a part of the end which you leave hanging off, place your part on top and position it, then pull the rest of the release tape out from underneath.

[Hudson Force]

Originally Posted by Delancey

Looks real nice.

Sometimes, depending on what you are doing you can leave the release tape on the VHB except maybe a part of the end which you leave hanging off, place your part on top and position it, then pull the rest of the release tape out from underneath.

I can imagine this technique working with some applications. 'not so much for me with this project. In order to make the tight radius turns at the ends of my portlights, I needed to cut sectors out of my tape every inch around the turn and this left me with, not one piece of release tape to pull, but about 24! I can imagine that there might be a substitute "release tape" material that could be placed over the VHB surface and pulled at the application as you describe, but I did not search this possibility.

This does seem like a good idea.

[Kadukuguam]

I have the same problem. It looks like you have replaced the old gasket with a new one. Where did you get them?

[Hudson Force]

Originally Posted by Kadukuguam

I have the same problem. It looks like you have replaced the old gasket with a new one. Where did you get them?

About 15 years ago I purchase these extrusions from Griffith Rubber Mills in Portland, Oregon. They are in their online catalog of "H" gaskets (1" to 1/4").
The only difference from the original Morgan gaskets is that the tight radius turns are not molded in and the locking strips are black instead of white.

I believe Griffith Rubber Mills sells these in fifty foot rolls. At the time I sold my excess from my application on my Morgan 41' to a guy with a 33' and he had a sufficient amount to complete his portlights.

[Hudson Force]

I finished the six fixed portlights on my port side today...



I'm fairly pleased with them. I guess I could have had them less proud if I had routed out a setting for them, but the VHB double-sided adhesive seems to have done well. They do cover a greater surface area than my former portlights, but I wanted the surface for best adhesion. Without the gaskets I do have more light below, but we've been quick to cover them with items on the shelves. We get more than enough sun in the cockpit and we like things dark below.

I'll be turning around in my current slip tomorrow so I can start on the starboard side.
Half done!

[Delancey]

Nice work. Looks good!

[landonshaw]

If the radius is not molded in, then did the gasket lay flat or did it bunch up leaving gaps. I have been chasing leaks also. Luckily I always find some other problem to fix first.

So I like the company gasket supplier thanks. Now for the corner problem and maybe I will try.


Sent from my iPad using Cruisers Sailing Forum

[Hudson Force]

Landonshaw, If you look closely at the photo in post #1 of the old replacement port that I installed about ten years ago using the Griffith Rubber Mills gasket without the molded end turns, you will see that the gasket is not as wide at the ends as the longer spans above and below. This is because I tapered the locking strip and omitted it from the turn. Omitting the locking strip at the tight radius allowed the gasket to fit and still kept everything tight. I was difficult to press the main portions of the locking strip into place and hopelessly distorted to include them in the turn.

'wise of you to notice this problem!

[Hudson Force]

I was asked a question by another cruiser today. I knew this question was coming and I thought I was ready for it. People just are not yet accustomed to seeing portlights sitting against the hull without frames or fasteners. The question was, "Don't you worry about the force of a storm wave knocking those acrylic portlights off?"

Well, bottom line is that I can conjure up a worry about most anything! I suggested that this same 3M VHB tape is holding huge windows to skyscrapers and windshields to 100 mph cars. My added thought is that the 3/8" plates are larger than the holes they cover and wave pressures would be pressing them to their position. I don't envision them being forced out from the inside, but there is the thought of having them peel away at their edge. Regardless, I'm not going to be truly worried about this.

Hey, if they fail, you guys will be among the first to know! I'll be giving them a test sometime. I doubt if I'll be offshore in a significant storm, but I do anchor in a tropical system now and then.

Oh, another factor in the mix,- total cost of materials when discounting my own labor and considering 12 fixed portlights comes to $75 each!

[Hudson Force]

'just a final report as I finished the last of the 12 portlights today.



I did end up with some success bending the two larger aft acrylic portlights. These required a bit of bending. A little research led me to the need to heat the acrylic to over 180* F to make a bend. All I needed was about a quarter inch over the 31" length. I put pressure on the outside with aluminum foil against the acrylic surface, using a taught block & tackle line with pads braced against the portlight. With this pressure holding them in the desired bend, I heated the inside of the acrylic portlight with a hair dryer that managed to reach a temperature of about 185* F for about ten minutes. My first attempt were with a wind outside and heat was removed to fast, but later, in still air I managed to reach the temperature for a bend. My other choice was to resort to a propane torch, but I managed with the gentler heat source.