I purchased a product called brown bread that is a copy of dynamat extreme. I wanted to put it behind the door panels, floor pans, behind back seat, etc... Will it retain moisture underneath it. In particualar on the doors. I want to intstall it right on the metal (not on top of the watershield) so that it will dampen the sound better but I don't know if the moisture coming in the door will break it down or get retained and cause rust.

Yes it will retain moisture and trap it between the door skin and the insulation. There are holes in the bottom of the door because water gets in there. I like it in the other places you mentioned but not in the doors and not in the roof. Follow the factory lead when doing the engineering.

-Mark.

Are you familiar with the dynamat extreme product, it's not like jute isulation. It is a tar type of thin material with alumium backing. Just making sure.

not realy familiar with that particular product but I can visualise it.

I am familiar with rusty doors and other parts. I am also familiar with trapping moisture between insulation and sheet metal. Ever seen what a piece of carpet will do to a trunk pan that has a spoiler mounted above it.

I used to do a lot of engineering of comercial HVAC equipment and general building enviornmental issues. We did experiments with different types of insulation and various methods of instalation. Pig hair, coated, closed cell foams, blanket, spray on, etc.

The material you mentioned sounds like it would work well for sure in most places but the inside of the door worries me. The rain water and wash water will get down in there. It will need to run out the door bottom drain holes. The water may end up between the insulation and the door skin. If it gets behind that insulation, it will never dry. The door will rot. If you could seal it perfectly and the seal did not deteriorate over time and useage it will be fine. Your crafsmanship and the integrity of the product over time will be very important.

You could use an asphalt based sound deadener as the factory did. If you think about it, they used that stuff only inside the doors. Not in the roof, not on the firewall, not anywhere else. The wheelwells have something like that in there. There is a reason. They could not do it the way they did in the roof, firewall, trunk bulkhead, floor etc.

It is your car and you should do it the way you want to. Don't just take my word for it. I might ask the manufacturer of the material what they recomend for inside the door attached to the outer skin.

-Mark.

stinger69, Dynamat and the other products are basically high tech asphalt sheets. Dynamat Extreme is like a layer of melted tar - it is very pliable and sticky. Once this stuff is installed, it won't come off. If installed properly, water should not be able to get between the insulation and sheetmetal. Just be sure to clean the metal off good before installation.

I have heard that you should install a 12x24 piece on the outer doorskin and then install a piece over the inner door panel. I think I am going to stick the inner piece on the back of the doorpanel. That way, if I need to get inside the door to fix something, I don't have to tear up $50 of Dynamat.

If you install the insulation as discussed above, you shouldn't retain moisture inside the doorpanel because you only istalled insulation on the vertical panels. There are several vent holes on the bottom of the door and the gap in the top where the window slides where evaporating moisture can still escape.

gheatley. I think that if you stick the other piece on the inside of the door panel it won't do as much for the sound deadening. I think the puporse of that asphalt material is to be applied directly to the metal to absorb vibrations and sound waves. I could be wrong. I personally am not planning on getting back inside the window area once I have finally! done the proper adjustment of the windows.

before you do install this stuff....clean the area up and then swab it with alcohol....it even helps to heat up the area a little bit...i like to use a space heater, or a heat gun....but you only really need to do that if it's super cold out...and with brown bread/Edead/raammat/peel and seal/b-quiet/....you really won't need to heat it up if it's nice out, as they all stick rather nicely...

and yes, if installed properly....there's no way moisture should get under there http://www.camaros.net/forum/smile.gif

i think you'll find that you'll notice the greatest deadening of sound by doing the outer door panels, and as much as you can get on the firewall....doing the floor didn't do much for me....as compared to those two areas....

the purpose of all of those products is mass loading....ie: just adding weight to drop the resonant frequency of the panel you are adding it to....which lets less sound in....and if you are a stereo freak...it lets less sound out....both are good http://www.camaros.net/forum/smile.gif

i think Edead is on sale right now....maybe... www.edesignaudio.com (http://www.edesignaudio.com) it's an asphalt layer with an aluminum backing....works great....

chevyboy, the door panel fits very tightly to the door with several clips and screws. You should be able to get most of the vibration dampening effect with the Dynamat pressed firmly against the metal panel.