Coating on sound proofing foam

[Dspcole]

1987 42CL
The coating on the sound proofing foam in the engine room overhead is all crazed, cracked, and peeling off. It is easy enough, if somewhat tedious, to remove but is there a product that could then be applied? Or why bother?

 

[Comodave]

I just scraped off the old foam sound insulation on our boat and replaced it with 2” 2 pound per square foot insulation from Soundown. It was quite a bit of work but should help reduce the sound from the engines. Won’t know how much until we launch in the spring.

 

[Dspcole]

Actually our foam is in great shape. It is only the white paint like substance that is deteriorating. I would like to remove the “paint” and recoat.

 

[Larry M]

Reach out to Steve at Soundown, Fort Lauderdale. He’s a Forum member.

https://soundown.com/

 

[Dspcole]

This photo will show the problem

 

[Comodave]

I have no idea what would work on foam. I still think it may be just as easy to replace it, maybe not as cheap though.

 

[Keysdisease]

Acoustic foams "absorb" noise, and are not noise barriers. Basically they cover hard surfaces that would reflect noise and increase volume by reverberation. Because these acoustic foams are designed to absorb noise, they are open cell and also absorb gasses found in the engine room. These gasses will shorten the life span of these foams significantly, that's why almost all engine room foam products have a "face." The face is typically a very thin urethane or polyester vapor barrier, thin to allow as much noise as possible through to be absorbed.

The photo looks like it may be a white urethane face. These tend to crack and shrink as the picture indicates. I am not aware of any spray or brush on product that will stabilize this face and not impact performance. Be advised that these foams can be sensitive to many solvents found in various coatings.

You could cover with perforated aluminum, but that would be an expensive way to put lipstick on a pig. Removal would probably increase noise level measurably, but not noticeably, if there is no vinyl or lead barrier in the foam composite.

Leaving it in place to deteriorate may lead to clogged air filters and bilge pumps, so removal or replacement are your 2 best options.

And Larry, I hear Steve @ Soundown has retired

My $0.02

 

[Comodave]

Agree that if it is just foam it will do almost nothing to impede diesel noise. We just stripped off the original 1/2” foam sound insulation on our current boat and replaced it with 2” 2 pound per square foot insulation from Soundown. Boat is in winter storage so I have not run it yet. It doesn’t appear that there is a decoupler layer in your current foam. If not I would absolutely remove it and put in some quality sound insulation.