# Acoustic Insulation for engine room?



## T37Chef (Oct 9, 2006)

Which would you recommend for an engine room application? I have a piece of Vinyl/Foam with Mylar Face with PSA from Sundown that I like and was going to order it but thought I would pose the question to the forum first 
Soundown - Barrier Acoustic Insulation, Carpet Underlay, Acoustic Absorption Materials

I am probably going to use something 1" or less thick, its a tight space.

Thoughts...thanks


----------



## Flybyknight (Nov 5, 2005)

Did a study on this subject several years ago, and what I found was the most effective sound deadening composite is lead foil sandwiched between 1 inch (or more) of foam and secured with a pressure sensitive adhesive.
Yes, psa's have sound deadening qualities too.
Hope this helps. 

Dick


----------



## SloopJonB (Jun 6, 2011)

Flybyknight said:


> Did a study on this subject several years ago, and what I found was the most effective sound deadening composite is lead foil sandwiched between 1 inch (or more) of foam and secured with a pressure sensitive adhesive.
> Yes, psa's have sound deadening qualities too.
> Hope this helps. Dick


Flyby, Is that lead foil in the middle between TWO layers of foam? Can you make this up yourself in the engine room or does it have to be pre-manufactured sheet goods?


----------



## CapnBones (Sep 20, 2010)

My plan was to use Dynamat. You can do a google search to find it. It is a tad on the pricy side, but I have seen very good results and it is highly regarded in the automotive community for its sounds dampening properties. Also it is not very thick so you surrender less space to it. 

I plan to insulate my engine room/compartment with it this season. Has anyone here used it on a boat?


----------



## Allanbc (Apr 19, 2007)

CapnBones said:


> My plan was to use Dynamat. You can do a google search to find it. It is a tad on the pricy side, but I have seen very good results and it is highly regarded in the automotive community for its sounds dampening properties. Also it is not very thick so you surrender less space to it.
> 
> I plan to insulate my engine room/compartment with it this season. Has anyone here used it on a boat?


I bought Dynamat to do my engine compartment last year but never got to it. I have it on my schedule this year. I like the thinness of it because my engine compartment is really tight already. I'm thinking of adding more to the outside of the engine compartment if I'm not satisfied. Adding an inch all around inside my engine compartment is just not practical.


----------



## jrd22 (Nov 14, 2000)

I've used Barrier 104 from Hamilton Jet with good success. They have some good information available on sound insulation at the bottom of the page.
Link here

Noise & Vibration Control Products


----------



## Faster (Sep 13, 2005)

We've used the foam/lead/foil panels with good results, but the best sound deadening we ever did (on a previous boat) was an old dentist X-ray apron draped over the block.

btw a tremendous amount of noise reduction can be achieved by isolating and eliminating vibration of locker doors, companionway steps, stove racks etc. Those kinds of rattles contribute disproportionately to the overall noise while motoring...


----------



## chef2sail (Nov 27, 2007)

Check these out from Sailors Solutions. I installed 2 years ago with good results. very very easy to install

http://sailorssolutions.com/index.a...121&SubCategory=Soundproofing&Category=Engine Room

LED lighting, soundproof, Sailor's Solutions Inc.

Dave


----------



## jsaronson (Dec 13, 2011)

Jamestown Distributors sells a kit. Haven't tried it.


----------



## deniseO30 (Nov 27, 2006)

I know it's a no no.. but fiberglass does such a great job of killing noise. I have lots of FG ductboard left over from various installations over the years. I may just use some it to soak up the sound and just remove them if mold starts growing. inside the Lazrette lid and the engine front panel in the galley which are parts of the engine compartment the resonate the most.

_ducks out of sight and hides behind sofa_


----------



## JiffyLube (Jan 25, 2008)

I used some 1" Insulmat under my engine floor boards (haven't finished the engine compartment yet), but to tell you the truth I don't notice a real difference in sound deadening.


----------



## Flybyknight (Nov 5, 2005)

SloopJonB said:


> Flyby, Is that lead foil in the middle between TWO layers of foam? Can you make this up yourself in the engine room or does it have to be pre-manufactured sheet goods?


I purchased the sheet already laminated in a sandwich construction.
It was so long ago ~30 years, that I can't possibly remember the source.
If you were to do the lamination your self, then I would suggest a solvent based psa adhesive (Ashland Chemical Co.), failing that, a water based psa woukd probably work based on the mfgrs recommendation.
I can not over emphasize the need for a PRESSURE SENSITIVE adhesive.
Foil is easily available on line.
Hope thia helps.
Dick


----------



## chip (Oct 23, 2008)

I used to do a lot of audio recording, and while I never got too far into sound treatment, I was always told that the thing that stops sound is mass. I'm not surprised that some of the other people in this thread had the best luck with lead. A lot of music studios and things use soft sound treatments, like foam, fluffy fiberglass or rigid compressed fiberglass panels, but they're doing that more to "tune" the room by lessening echo and preventing the buildup of certain frequencies when instruments are being played and recorded in there, not to sound-proof the room. Although every little bit helps, going with something less dense will likely block proportionately less sound. At least theoretically.


----------



## lajimo (Sep 5, 2011)

Recent episode of Holmes on Homes emphasized the need for a dead air space between sound absorbing sheets. They got 50dB of attenuation that way, especially effective for lower frequencies (like engine noise).


----------



## Sublime (Sep 11, 2010)

Anyone try that coating they use on the wheel wells of cars to reduce road noise?


----------



## Brent Swain (Jan 16, 2012)

A friend in a sound lab, told me that when using lead on foam, the foam makes no difference whatever. It's the lead doing the sound deadening. 
Carpet is just as effective as fibreglass, just a lot tougher, and easier to deal with.


----------



## Flybyknight (Nov 5, 2005)

Brent Swain said:


> A friend in a sound lab, told me that when using lead on foam, the foam makes no difference whatever. It's the lead doing the sound deadening.
> Carpet is just as effective as fibreglass, just a lot tougher, and easier to deal with.


Yes, I agree.


----------



## superiorvoyager (Jan 3, 2009)

Acoustic Insulation sounds great but it is expensive. I am thinking of a free solution for me.I have a lot 1" closed cell foam sheets (4x8)lying around and was thinking about lineing my engine compartment with this (this is fire resistant CSA compliant insulating material.) I know it probably won't work as well but would it help reduce the noise coming out of my engine room. The motor (yanmar ysm 12)is out right now for a rebuild so I could line the whole area and it won't cost anything but a little time.


----------



## miatapaul (Dec 15, 2006)

lajimo said:


> Recent episode of Holmes on Homes emphasized the need for a dead air space between sound absorbing sheets. They got 50dB of attenuation that way, especially effective for lower frequencies (like engine noise).





Brent Swain said:


> A friend in a sound lab, told me that when using lead on foam, the foam makes no difference whatever. It's the lead doing the sound deadening.
> Carpet is just as effective as fibreglass, just a lot tougher, and easier to deal with.


I think the foam acts as an air space, so it in it's self does not stop much sound, but it creates an airspace.

By the way Dynamat is really just asphalt, so there are adhesive roofing materials that work the same, again really just the mass of the heavy coating. The stuff does smell pretty bad though. I have used it successfully in car installations.


----------



## chucklesR (Sep 17, 2007)

Vacuum passes neither heat nor sound. 
On the other hand you can not find it in convenient easy to install panels unless you work for NASA or some other organization that doesn't have to count (pinch) pennies.

Until then us common folk are best off with one of few solutions, add mass (lead) to absorb the sound or add vibration dampening to lessen the noise and of course to add baffling - i.e. foam or sound reflective surfaces (the paint on stuff, and perhaps carpet).

If you "really" want to insulate for sound - get a roll of sheet lead and apply your own lead sheet (use a PSA) to your existing walls - after all lead is soft and bendable and cuts easy.
Lead Sheet from Rotometals

Don't make your engine compartment so well 'sound' sealed that it starves for air.

Of course racer's hate mass, but how many of them care how loud the engine is?


----------



## superiorvoyager (Jan 3, 2009)

Of course the problem with sheet lead is it still costs money. My reason for thinking of using Closed cell foam is that I already have it in 4x8 sheets, both 1" and 2". At the same time if it won't make any difference I won't waste my time but it seems to make sence that it would be better than nothing.


----------



## jimgo (Sep 12, 2011)

So, would something like this have a max. temp. that's too low?
McMaster-Carr

At the recommendation of some of the guys on another forum I used to frequent, I used that on a car to help acoustically insulate the passenger compartment. I realize the inside of an inboard's engine compartment will likely get warmer than my old car, but I can't help but wonder if this might not help. I mean, the inside of the engine compartment is largely made of wood; what's the max. temp. there?

Just a thought...


----------



## katsailor (Jan 6, 2013)

I am in the same situation, I am in the middle of a repowering project and asked the forum for input on lining the inside of my engine compartment to reduce the engine sound.
Here is a link to the thread http://http://www.sailnet.com/forums/diesel-engine-forum/97100-paint.html

I am going to use 1 inch sound absorbing foam I purchased form McMaster Carr. I can not give good reference as to how good it works because I never heard the engine run before I bought the boat. All I can compare it to is how loud is with the engine compartment door open or closed and how loud the engines sound on similar boats. just my .02

The compartment was originally lined with foam that has deteriorated over the 30 years.


----------



## hellosailor (Apr 11, 2006)

voyager, my understanding is that the closed cell foam, if it is high density, will stop high frequency noise, much as ear stopples will. If you've ever used these you may note the effectiveness differs greatly from one brand (foam type) to another.

If you want to stop low frequency noise, you do that by converting the energy into heat, and that requires mass. That's what lead sheeting is for. The high mass of lead absorbs large amounts of vibrational (acoustic) energy and converts it into heat. You can't do that with anything unless it is DENSE which is why they still use lead.

Physics rules, there's no other magic solution. There are some high density plastics like "sorbothane" and others but you will find them as pricey as lead. Bottom line, you can pay the piper, or listen to the the pipes.

Or get some of those expensive Bose active headphones.


----------



## SloopJonB (Jun 6, 2011)

I've seen a commercial lead/foam sheet that has a fairly dense black "polyfoam" type of foam with a sheet of lead sandwiched to it and a foil backing on the lead side. How does the group think this might work if you first lined your engine compartment with sheet lead then attached the foam product with the lead side "in" - this way you'd have the foam creating the dead air space between two skins of sheet lead.

It would cost several $hundred but the theory seems to fit well with the comments in this thread.


----------



## katsailor (Jan 6, 2013)

Sounds like a trade off and a function of how much money do you want to spend, although I have noticed that my sound-proofing is entirely efficient when I shut off the motor.


----------



## hellosailor (Apr 11, 2006)

Jon, I suspect the lead that is mounted against the engine compartment walls will still transmit some sound. You might try using "Dynamat" against the walls, that's what it is designed for. Not cheap but supposed to be effective.


----------



## superiorvoyager (Jan 3, 2009)

miatapaul said:


> By the way Dynamat is really just asphalt, so there are adhesive roofing materials that work the same, again really just the mass of the heavy coating. The stuff does smell pretty bad though. I have used it successfully in car installations.


What are we talking about specifically by "adhesive roofing material". do you mean the brush or roll on stuff you put over felt or use for roof repairs etc. If so I could just coat the plywood that encloses the engine compartment and then add foam to the outside to add "dead air space"


----------



## mgiguere (May 22, 2004)

I installed soundown (salem ma) 25 yrs ago around the engine box on my Apache 37 when I replaced the gas engine with a Volvo diesel (much louder). Made huge difference...can hardly hear the engine running. The only disadvantage is the weight of the wall that has to be occasionally removed for winterization. But, a great solution. Hope that helps. Soundown - peace and quiet for architectural, marine, & industrial applications

Moe


----------



## Flybyknight (Nov 5, 2005)

SloopJonB said:


> Flyby, Is that lead foil in the middle between TWO layers of foam? Can you make this up yourself in the engine room or does it have to be pre-manufactured sheet goods?


Sure if you have the lead foil and a good pressure sensitive adhesive that is compatible with the foam you use.
The really good high end foam is rubber.
Dick


----------



## T37Chef (Oct 9, 2006)

Keep in mind, these photos were taken before I finished the installation, I had not finished taping and sealing all the areas, which I Have done now. I did not close the engine in, I left the aft section open for good air circulation, combined with a new bilge blower and engine I believe it will be much cooler and quieter...or so I hope. I painted everything while I was at it, why not 

Hopefully I will be launching soon, and will post if it made any significant reduction in noise and/or heat.


----------

