Fiberglass mat exposed

[eze2bme]

1979 43DC, fresh water since new. Some of the fiberglass mat is beginning to show through on the top of my forward hatch, the opaque (yellow) portion. What is the best fix? Thxs.

 

[captddis]

I have the same issue and I have been told to sand it smooth and put multiple coats of Awlgrip clear on it.

 

[Dan Mapes]

I was thinking similarly we have the same issue. I wonder if West System with the clear no blush hardener would work well?

 

[Cricket]

You would have to coat the West System with something to protect it from UV damage.

 

[SKYCHENEY]

Or cut it out.

Here is what I posted a few years ago:

Okay, we all know how those Hatteras hatches look over time. The unpainted glass yellows and looks like crap. Well, I'm finally gonna do something about it.

I pulled the hatch (mine is the big 30x30 vent scoop one). I'm going to cut out the scoop, rabbit a notch for the new smoked plexi to sit on and caulk it in with Boatlife Life Caulk.

Here's the deal. Acrylic expands at a rate of about 1/8" in 24" per 100 degrees of temp change. I plan to leave 3/16" all the way around for the caulk and I plan to set it at about 100 degrees ambient temp. This will give me room to go from zero to 200 degrees with only 1/16" movement on any side. Since Life Caulk is a hybrid silicone and polyurethane, it is suppose to be able to move that much with no issues. They say to make the caulk joint 3x bigger than the expected thermal expansion, so that is covered.

Oh, and my plan is to let the 1/2" plexi sit down 1/4" with 1/4" proud and that upper level will be rabbited to cover the caulk joint. Understand?

I spoke to Tom Slane and he said not to do it. He has seen too many that are not done properly and when they expand, they have no where to go so they bow up and down thus creating crazing cracks and failed caulk joints. But.....I think I have it figured out.

 

[Salty Dame]

I did basically the same thing but used half inch clear Lexan. Maybe the most worthwhile project I've done on the boat. The light below is fantastic.

 

[jim rosenthal]

I did something different. I painted the entire hatch cover with white AwlGrip. It still lets a fair amount of light through, and it looks much better. Also, it does not leak.

 

[bobk]

Or cut it out.

Here is what I posted a few years ago:

Okay, we all know how those Hatteras hatches look over time. The unpainted glass yellows and looks like crap. Well, I'm finally gonna do something about it.

I pulled the hatch (mine is the big 30x30 vent scoop one). I'm going to cut out the scoop, rabbit a notch for the new smoked plexi to sit on and caulk it in with Boatlife Life Caulk.

Here's the deal. Acrylic expands at a rate of about 1/8" in 24" per 100 degrees of temp change. I plan to leave 3/16" all the way around for the caulk and I plan to set it at about 100 degrees ambient temp. This will give me room to go from zero to 200 degrees with only 1/16" movement on any side. Since Life Caulk is a hybrid silicone and polyurethane, it is suppose to be able to move that much with no issues. They say to make the caulk joint 3x bigger than the expected thermal expansion, so that is covered.

Oh, and my plan is to let the 1/2" plexi sit down 1/4" with 1/4" proud and that upper level will be rabbited to cover the caulk joint. Understand?

I spoke to Tom Slane and he said not to do it. He has seen too many that are not done properly and when they expand, they have no where to go so they bow up and down thus creating crazing cracks and failed caulk joints. But.....I think I have it figured out.


Sky,

How did it work out? And, why didn't you buy a piece of fiberglass that was made to be used to let light into buildings. There are many available, and they have a lower coefficient of thermal expansion than unreinforced plastics.

Bobk

 

[lumina]

Hi All,

I took the same route as Sky and am glad I did. Provides a lot more light into that fwd cabin and it logs great.

 

[SKYCHENEY]

Or cut it out.
.


Sky,

How did it work out? And, why didn't you buy a piece of fiberglass that was made to be used to let light into buildings. There are many available, and they have a lower coefficient of thermal expansion than unreinforced plastics.

Bobk

It has worked out great. I like the extra light and the clean look.