Inexpensive Soundproofing?

Kauaiboy206

Petty Officer 2nd Class
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Mar 9, 2017
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133
Came upon a product by SilverRboard; it's an inch thick material, soppouse to be used for homes to add soundproofing. Wonder if this is a good & cheap alternative for dampening engine noise on a boat. It's got reflective front for heat, moisture resistant also. PRODUCT PRICE @ $25 for 5 sheets dimensions are 1 inch thick and 24"?48" sheet.
 

rallyart

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Jun 7, 2008
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SilverBoard is an expanded foam and will do a good job of keeping heat from the engine from coming through. I do not believe you would find it effective at reducing engine noise as it lacks mass to cut the low frequency noises from transmitting. In an underfloor construction setting it would stop some sound transmission by absorbing foot falls but there would be better products do put in a theatre room.

The first key to eliminating sound from the engine compartment is to eliminate any direct line of sound transmission, like a small opening. Next is to stop the sound transmission through absorbing the energy with mass or a varied mass structure that dampens several frequencies. The SilverBoard is not expensive if you want to try it, but I would not count on much change. Tape any joints, as that will help.
 

Kauaiboy206

Petty Officer 2nd Class
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Mar 9, 2017
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133
SilverBoard is an expanded foam and will do a good job of keeping heat from the engine from coming through. I do not believe you would find it effective at reducing engine noise as it lacks mass to cut the low frequency noises from transmitting. In an underfloor construction setting it would stop some sound transmission by absorbing foot falls but there would be better products do put in a theatre room.

The first key to eliminating sound from the engine compartment is to eliminate any direct line of sound transmission, like a small opening. Next is to stop the sound transmission through absorbing the energy with mass or a varied mass structure that dampens several frequencies. The SilverBoard is not expensive if you want to try it, but I would not count on much change. Tape any joints, as that will help.

Im currently restoring a 79' Sun Runner 19ft cuddy so everything is gutted out and have full access for modification. The engine cover is still good but the material on its wall is crumbling like dried up foam. First was to remove and replace it, the rear seats had acess holes that was just covered with a vinyl covering. Will be changing that with a plywood that will be painted with rubber coating and eliminate the hole and install hinges for acess instead. The back rest will also receive a ruber coating on its inside panel before I redo the vinyl rest. The engine cowling will also receive the same treatment prior to installing a sound barrier material and will probably end up painting the outside "rubber coating & finish deck coat paint" or carpet depending on how it will look. I also removed the barrier from the floor that seperate the engine from the floor compartment' rubber paint and sound proofing material also. The middle deck board will also receive the same treatment underside of it and carpet above. I already have access to the rubber coating as my company uses them to paint pressure treated wood before it gets buried on the soil for further protection from elements "fence post". The stuff that are marketed for sound proofing seems highly expensive and over priced in my opinion, so Im trying to see what options I have out there.
 

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Kauaiboy206

Petty Officer 2nd Class
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Mar 9, 2017
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133
What about fat mat or dynamat?

Those are still on the pricey side of things, I'm going to try those materials. I just saw similar items at home depot, their in the thicker side and the meterial feels pretty decent with the foil face.
 

Ned L

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Sep 17, 2008
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Be aware that probably most "foam" insulation (sound deadening) types of products burn like gasoline soaked rags. You should check to see if they are specifically marked as flame retardant.
 

rallyart

Lieutenant Junior Grade
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You want to dampen sound in the engine compartment with an absorbent material which will stop sound reflection. Products like Rocksul (rock wool insulation) does this. To stop sound from traveling through you need mass so a product like automotive undercoating can help with that. Sound control is a black art that is hard to manage. Good luck.
 

dpoff

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Nov 27, 2004
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Whatever you chose, just make sure that it is rated for marine use.
 

harleyman1975

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May 12, 2003
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Check out a company called Cyber Bridge Enterprises. I bought their marine rated coast guard approved sound deadener foam. It is 2 layers of super dense foam separated by a sheet of lead with a mylar outer surface. It is adhesive backed and sticks pretty darn good. I paid about 125.00 for a 4x4 sheet I bought 3 sheets and have one full sheet left over but I plan to do a little more insulating. Cut the sound in half!
 

Kauaiboy206

Petty Officer 2nd Class
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Mar 9, 2017
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Finally got around to wrapping the engine cover on the boat. I ended up using the seal king rubber flashing with heat protection top. I had trouble getting it to stick at first even after thoroughly cleaning and using acetone to remove any left over dirt. I had some rubber spray and ended up applying it, letting it dry. Works like magic and attached very well. Already made a big difference in sound performing the knock test; will most likely be applying the same material on the transom area. $13 dollars per roll =D
 

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