dynamat as a heat shield/sound deadning?

[jmanjeeper]

I need to replace the insulation on the inside of the engine cover because the old foam/foil one is just falling out. Do you guys think dynamat would be a nice way to go? I'm not sure about the heat, but it is used on firewalls in hotrods to keep the noise down, and I would think a hotrod would make about the same if not more heat than my 4.3l. Thanks in advance!!

Josh

 

[Bondo]

Re: dynamat as a heat shield/sound deadning?

Ayuh,.....

Go for it,..... A Hot-Rod would be Alot Higher Temps.....

 

[rlb81]

Re: dynamat as a heat shield/sound deadning?

There might be a coast guard requirement on the insulation, might want to look into that also

 

[oops!]

Re: dynamat as a heat shield/sound deadning?

as far as sound....generally dyanamat is the product of choice

 

[TilliamWe]

Re: dynamat as a heat shield/sound deadning?

I asked about insulation/sound deadening on my boat on a different forum last year and got these links:

http://www.marinefoam.com/engine-soundproofing.html?page_type=engine-soundproofing&link_type=image

http://www.foamdistributing.com/products/acousticeggcrate.html

And this reply:
"I installed some great stuff (my opinion, of course) from Bonded Logic about 5 years ago... it's a cotton fiber insulation coated with the reflective layer. Light weight, easy install.. and effective sound insulation... under my hatch and deck. It is (was?) sold thru camping world outfit I believe.. intended for generator dog house... so temp certified. fwiw..."

I have not done anything with mine yet, because the cover doesn't actually get hot, and the egg carton type black stuff I had wasn't blocking any sound at all, apprently. I can't tell the difference without any foam on there at all.
Good luck.

 

[reelfishin]

Re: dynamat as a heat shield/sound deadning?

I'm not sure if Dynamat would be the best choice in a boat, it's a bit on the heavy side and it's hard to make it conform and adhere to odd shapes. I think you would be better off with a thicker, lighter insulation, but I'd also be concerned with flammability as well.
I've used Dynamat and similar products in cars and trucks, but don't see it adhering well to the rough undersides of most fiberglass hulls and parts.
It's also too expensive.
I re-insulated the engine box on my one boat and used a foil backed insulation that I got from a heating and air conditioning supply house. It worked great and was easy to work with. It's also mildew resistant and works well as a heat shield too. I doubt if I added more than a pound or two overall as well. A good quality trim cement and the oem clips are all it took to hold it in place and it was cheap enough and easy enough to install that even if I did have to redo it one day, its not a big deal. the old insulation had been pulled apart by rodents over the years, but it sat for over 10 years abandoned before I found it. I don't foresee that being a problem now though.

 

[Offroader]

Re: dynamat as a heat shield/sound deadening?

Re: dynamat as a heat shield/sound deadening?

Dynamat is a soundproofing cover, NOT a heat shield.

You could structurally compromise your boat by doing this.

You might, space permitting, install Dynamat underneath the heat shield.

But this would mean you would spend double the money.

 

[jmanjeeper]

Re: dynamat as a heat shield/sound deadning?

thanks for the replies! I used to be a Pro-Audio installer and was also worried about the weight but they have this now:

"Dynamat Xtreme damps four times better than Dynamat Original and weighs at least 50% less. Dynamat Xtreme's aluminum constraining top layer also makes it well suited for situations where heat is a problem, such as on the floor and firewall near an exhaust or header."

Not sure why Offroader said "Dynamat is a soundproofing cover, NOT a heat shield. You could structurally compromise your boat by doing this." But hey, I guess everyone has their opinions... I understand it is for soundproofing, BUT it is also used for soundproofing in HEAT AREAS, ie, FIREWALL OR NEAR EXHAUST.


Actually come to think of it, I am almost positive the crap[ in the cover now isn't very heat resistant, its just foil backed with a really loose egg-crate like foam. hmmmmmm
Thanks again for the post, I am going to look into the other ideas you guys have and see if I can get a cheaper route, if not I may still go with Dynamat because I can get it pretty cheap from the audio shop I worked at...

 

[jmanjeeper]

Re: dynamat as a heat shield/sound deadning?

I found the bonded logic stuff and wanted to post it for you guys:

"The Insulator Thermal/Acoustic Insulation is an extremely versatile and superior performing product that can be used in automobiles, trucks, buses, RV's, boats, aircraft, residential and commercial building.

The Insulator brings fire, fungi, and corrosive resistance to an insulation product that is formaldehyde and resin-free.

The Insulator?s natural fibers provide a non-itch padding that is easy to handle and install."

Boats & Watercraft Uses:

* Engine Covers
* Inside Hull
* Generator Compartments
* Pump Housing
* Bulkheads & Overhead

This was all on the website:

http://www.bondedlogic.com/insulator.htm

However trying to find the pricing has been a little illusive.

 

[reelfishin]

Re: dynamat as a heat shield/sound deadning?

I found the bonded logic stuff and wanted to post it for you guys:

"The Insulator Thermal/Acoustic Insulation is an extremely versatile and superior performing product that can be used in automobiles, trucks, buses, RV's, boats, aircraft, residential and commercial building.

The Insulator brings fire, fungi, and corrosive resistance to an insulation product that is formaldehyde and resin-free.

The Insulator?s natural fibers provide a non-itch padding that is easy to handle and install."

Boats & Watercraft Uses:

* Engine Covers
* Inside Hull
* Generator Compartments
* Pump Housing
* Bulkheads & Overhead

This was all on the website:

http://www.bondedlogic.com/insulator.htm

However trying to find the pricing has been a little illusive.

That sounds like your best option if it's affordable. The glass insulation I used was pretty cheap, I don't think I broke $50 to do the whole back of the boat.
See if they will send you a sample so you know what your dealing with.
My concern is that a self adhesive backed type of insulation or anything thin may not be all that easy to conform to and adhere to the rough underside of most fiberglass boat areas. I've seen that problem with Dynamat and similar products when the inner body areas on a car are coated or textured. The under hood area of my boats are really rough, there's enough stray glass strands there to shred your arm if not careful. It's even got a few 'dry' areas where they over did it with the chopper gun and there's just not enough resin to saturate all the fibers leaving a thicker, fuzzy spot. I took a brush and some epoxy resin and soaked those spots, but the entire underside of the hood was still really rough, way too rough to expect any standard spray adhesive or matting to stick, not to mention 35+ years of exposure to engine dirt and grease that no cleaner will ever completely remove. The under side of my hood had wire 'nails' embedded in the glass and galvanized washers that pushed over the pins to hold the insulation, and the edges were tucked under the over lapping panels. I was able to reuse 90% of the pins and made plastic washers to replace the galvanized steel ones that weren't reusable.
My main concern was to keep temps down on the rear deck, there are two seats on each side of the motor in this boat, and without the insulation, they would get a bid warm on a hot day, they are tolerable now with the insulation and the motor noise is about 1/3 of what it was. It mostly cut down on the rattles that came from the rear cover. (On my boat the entire rear opens up like a tilt hood on a truck, with the lid open, you have full access to the entire rear of the boat and motor).