sound deadening, Dynamat?

[geert1000]

I have a question about using a product like "Dynamat" in my car.
I will love the quiet, but will it "contaminate" such an original, no rust car by "hiding" the awesome solid floor?

[JamesL]

Is your car watertight. Properly so?

From the reading I have done, should you get any damp between the mat and the car, you are not going to be rust-free for long. That said, I know people have done it and are very happy.

[thelews]

it will contaminate it from an originality standpoint.

[GGR]

I'm not sure dynamat will do much to lower the noise level. Most of it comes from wind noise when the soft top is up. If high rpm on highway is an issue, go with a different rear end ratio. the drive wil be much more comfortable.

[johndillman]

To be done right, it is going inside, underneath the carpet and inside the doors, etc..  Consequently, I don't think it will be noticed, and I wouldn't hesitate to do it for a minute.  They can see your perfect floors from below. . .

My recollection is there are different products for heat and sound attenuation.  You might check out various ones.  Also some good sprayable ones are out there.  I hear good things about lizardskin.

Now if a higher/lower numerically differential fell in my lap, I wouldn't hesitate to take that suggestion, too . . .

John
'70 with perfect floors about to be installed

[Mike K]

When I decided to replace my carpets, I stripped everything out, no rust on floorboards; and installed "Thermo-Tec Suppressor Acoustical & heat Control Mat"
http://www.thermotec.com/products/14600-suppressor-acoustical-heat-control-mat.html

on top of that I laid "Thermo Tec Cool It Mat"  http://www.thermotec.com/products/14100-cool-it-mat.html 
and then laid the new carpets over the mat.

Very pleased with the results!

[Garry]

I am with John, It will spoil the originality.  If it is sound deadening, why not try to fit sound deadening mat to the underside of the carpets, unless they too are original and in perfect condition.

See Photo where deadening mat is fitted then is spray coated in a second deadening material.  Itt also makes it very easy to check that no moisture has entered and is killing the floors.

Garry

[GGR]

Best bang for the buck: earplugs!

[66andBlue]

Who is sitting in the passenger seat when you drive? 

[Jonny B]

Finally got weigh in on this. I really do not see a whole lot of downside to the Dynamat or similar (disclaimer - I just put it in m 250 SL when I was doing the heater core replacement). The stuff is completely hidden, does improve the sound level (not hugely, but it was an improvement for me). I put several small rectangles inside the doors and that was an incremental improvement. Is it not "original"? Yes, but completely hidden. Not a whole lot different than having the inside of the clock changed to quartz, but the face left from the original (did that one quite a number of years ago).  How is it that much different than putting in a sedan rear axle??

[geert1000]

Ha ! Since my car is a "radio delete" I just need a louder passenger? LOL!
Thx!

[geert1000]

I love this spray-on under carpet solution.
I'll Google it!

[Garry]

Geert,

The initial material was about 3/8 to 1/2 inch thick sound deadener mat that I cut to the shape of the carpet piece but before attaching then used the rattle can spray deadener you can buy in most auto stores that remains relatively flexible and sprayed one side and the sides.  Then used spray contact on both the under side and the carpet and joined both together. The carpets still fit in nicely and the spray on deadener stops any moisture getting into the deadener to quite a degree. It worked like a charm and is not visable when carpets are in place.

Garry

[RonB]

When I did the repaint on my 280 - I used "Lizard  Skin".

Comes in 2 types - heat resistant over the muffler area on the right passenger side - then a complete coat over everything.

really does a nice job of deading sound.

It is one of the favorites among street roders.

[jpinet]

I used Dynamat in my car, but took off everything I had installed on the floor when I noticed water came in. I'm not willing to have water sit between the Dynamat and my floor and slowly turn my floor pans into a flaky orange stuff. I did leave it in areas where water can't stay: transmission hump, firewall, side carpet. I found it did bring down noise level to a more comfortable level. But when I want a comfortable noise level, I dive my modern Audi! It's not as much fun though...
To replace the Dynamat on the floors, I used cotton padding I bought from my upholsterer. It comes in different thicknesses and can dry if it gets wet. It does a very good job at insulating heat and sound. It's much thicker than Dynamat obviously, but the carpets fit nicely on top and no one knows.

[Garry]

That cotton padding looks very like what I put on the carpets but it holds together much batter and is assured of not holding any water after being sprayed with the rubberised sound deadener before attaching to the underside of the carpet.

[jpinet]

That cotton padding looks very like what I put on the carpets but it holds together much batter and is assured of not holding any water after being sprayed with the rubberised sound deadener before attaching to the underside of the carpet.

Garry,
do you completely cover the batter with sound deadener sprayed on? Does the fabric not drink it in? And do they remain supple, sot hat you can bend them into place? I'm interested in you technique.

[BaronYoungman]

I did dynamat and I noticed a heat reduction and sound deadening right away.. just my 2 cents.  I dynamated everything including inside of the doors.
Bob

[thelews]

lead septum is the way to go.  Don't have to glue to horizontal surfaces.

[66andBlue]

I agree with John lead septum or a similar product "mass loaded vinyl" is the way to block airborne sound.
However, you also need to dampen metal resonance vibrations and for that Dynamat does a reasonable job but there are better products.
This site explains quite well what needs to be done: http://www.sounddeadenershowdown.com/products

[Autobob]

The body shop we used for floor pan repair used Lizard Skin first I had heard of it. We then used Hush Mat on the floor over the Lizard Skin. We have found the Hush Mat easier to form than  Dynamat. This 280SL will need to travel a 1/2 mile of gravel road twice a day when in service. Scary thought but country life it is.