I am insulating all the interior surfaces of my 68 roadster included the storage wells behind the seats. I have a rough estimate of how much material I should get but would like to hear from people who have done this job and have an accurate number. Thanks for any help. Chris

 

What are you hoping to accomplish with using Dynomat? If for sound and heat you are better using layers to isolate ie aluminum backed closed cell foam and mass loaded vinyl (what professional sound studios use) on top. If heat is the issue make your own version of Lizard Skin (cheap latex paint and ceramic *****) and spray that down first. For MLV you'd have to cut it as I've haven't seen anyone mktg kits.
I bought an al foil backed kit a few yrs ago, will be doing the above this summer in my 72 vert.

 

When I do a complete interior....I know the 36 square feet of Dynamat Extreme ( they sell in a box) will do from the base of the windshield all the way back to the rear seat mounting bolts....ten the rear of the car will take not quite a whole box again....but the left over sections you can sue inside your doors to make them more solid sounding.

Then I use the DynaPAD on to of this Dynamat Extreme.

YES it works.....I have a customer who is here on the forum whose 74 Corvette gets so cold when his A/C is running in the SUMMER...like he says...he can sell ice cream out of it.....But...all firewall plugs and wiring harness grommets were replaced also.

If you want to communicate with him...PM me and I will give you his screen name after I confirm with him that he is good with it.

DUB

 

50 ft of Fatmat did my 73 front to rear with 2 ft to spare.

 

Theres no reason to completely cover the floor with dynamat, serves no purpose except to make more money for dynamat. Dynamat is a dampener, all it does is stop the sound from outside acting on the panel and causing it to vibrate and transfer sound(in certian frequency ranges). All you need is enough to weigh down the panel enough to stop it from vibrating. It does nearly nothing to block heat and noise(in most frequency ranges).
To do it right is a 3 step process, you need a dampener(dynamat), isolator/disperser(jute works well for this) and a blocker(mass loaded vinyl is the prefered product). All three of these things together will make a huge difference but fitting all 3 under a formed carpet kit is a challenge.
Blocking heat is a different animal, theres really nothing on the market that does a good job installed on the inside of the car. The best way is a shield mounted on the under side of the car between the heat source and the body but touching neither, really a heat reflector with air in between itself and the body acting as a insulator. Products like reflectix(basically bubble wrap with foil on both sides) help but eventually heat soak and loose their effectiveness.
That said, dynamat alone will help but isnt really the correct way to go about doing it.

 

Another thing to add to what Dug and I are talking about is to make sure that any wholes in your firewall have the grommets intact. Take a look underneath to make sure that he trans insulation is still there. DEI has a small replacement kit I believe. I am going to try the Lizard Skin option as have read on many forums tha it provides some good heat insulation and is not as thick as some other solutions. I know of owners who have sprayed it on both sides of the floor. Don't forget about insulating behind the door panels, not sure in a vert how much good that does but it sure does cut down on some of the internal door rattles and makes for a more solid sounding thud when closing the door.
Do you run headers, have sidepipes as they affect heat and sound in a defferent way. Remember in a convertible, you're not going to cut down on a lot of sound but you can help with heat. Do you have a/c?

 

I agree with gdh not going to muffle much in a vert. Phil

 

I used one box to do my seating area, floorboards and console. You would need a little more than the box to do the entire car with the area behind the seats.

 

One 36 ft2 box of Dynamat Extreme completely covered the floors and up the wall behind the seats (with careful cutting). It would take a second box to do the rear storage area and the doors if you want to go that far.

Contrary to some opinions the Dynamat did significantly reduce road and exhaust noise AND heat from the fiberglass floors in my 73. The effect in a later steel floor may be different. Other than the Dynamat, I also replaced the factory jute backing under the carpets.

For the cost I would certainly do it again if I had the carpets out for interior work.

 

What gdh and dugsgms74 said-

Years ago I was a manufacturer's rep for Dynamat-

We had a display of a bell-



One had no dynamat the other has a piece of 1" x 1" dynamat piece...you could hear a demonstrable difference.

We originally sold a piece of about 12" x 18" for placing on a door skin or trunk or roof to stop rattles...really that was all that was needed on METAL. Then as everything else - if one piece is good- why not cover the entire car?

The point of diminishing returns- no way for all the money was it really worth it- but I was on commission!!!

Yes -it will reduce noise and heat- but IMHO- it's not the best way to do it.

I am more concerned w/ heat-covered the interior w/ Lizard Skin and the firewall/underneath w/ Zero clearance.

My thoughts- on the space shuttle they did not put the heat shields on the inside- and if you look at any duct work- the conditioned air is INSIDE the reflective materiel.

Sound? well it all depends on the frequency- look at some highend luxo cars- the engineers seal everything up and go to the extreme to use double pane widows. Oh- they use piece of there version of dynomat- and do not cover the compete panels- and this car sticker at $98K-so I'm thinking cost was no object.

The beige materiel- BMW version of Dynamat



How I did it-

Sort of like the trans tunnel blanket -but went up the firewall w/ it-



DSCN4675 by richardhayes454, on Flickr

DSCN4844 by richardhayes454, on Flickr

 

I used 40 sq ft of Hush mat in my 76. I also used metal foil tape for all the seams

 

YES...I have two brass coins that DynaMat had given me to show how it stops noise. One with nothing on it...the other one with a piece that does not cover the entire surface of the coin. When dropped...you can tell which one has the Dynamat on it...NO noise.

People can do what they want and that is fine....use what you want...BUT I have covered enough Corvettes that NOT covering the entire interior to the rear seat bolts is almost a waste of time. I am worried about noise...but I am MORE worried about the HEAT that the DynaMat system of products I use stops......and having customers be very pleased....and NEVER one complaint....why should I change when I have basically mastered how to do it and have templates made to save me time....and I am trying to stop the heat.

Richard454,

YES... I know what you are trying to convey by using the space shuttle and the ceramic plates being on the outside...and I AGREE WITH YOU....BUT...that is something COMPLETELY different. Corvettes are NOT entering the earths atmosphere at high speeds where friction is a factor....and these plates are protecting the structure of the shuttle so it does not come apart in mid air and boiling the occupants to a crisp.. I AGREE...STOP the HEAT at the side where the source is located.....BUT...I do not know many people who would want there underside of their floor pans shiny covered material. AND...the MOST IMPORTANT FACTOR is (in my opinion)....Some Corvettes have steel floor pans....and I would NOT want to apply a product to the underside of the steel floor pan with an air space...regardless how small it may be... and then the Corvette is driven in the rain and water gets between the floor pan and this covering...and incubates and rusts out the floor pans over time. Because given enough time...any coating applied to a steel floor pan IF exposed to a constant/severe moisture conditions will fail. For me...the amount of time to prep and condition/coat the floor pans so they would last a very long time is just not worth the possible gain in effectiveness that would be slight from what I have experienced in the method I employ. And on fiberglass floor pans....trapping moisture between the covering and the body will allow the water to have no place to go but up into the fibers over time....except for those areas where it will get hot and HOPEFULLY the moisture can get out.

It is very similar to leaving your Corvette covered outside all the time and never remove the cover and air the car out and wonder why things rust and it smells like mold and mildew and you get small blisters in your paint job.

dugsgms74,

I guess I am doing it right as per your description even though am using only two Dynamat products. The first is the Dynamat Extreme...then the next is the 3 layer DynaPad where there is a thick layer of a rubber product between two layers of foam. I used to use the Dynamat Extremeliner with the layer of lead ion it....and I still have several boxes....but using the DynaPad seems to not change the interior temps when tested.

That's all I got...I know it works. Do whatever makes you happy.

DUB

 

extechguy, I'm the customer DUB is referring to. Yes, last summer, with the A/C on max, it got VERY cold inside! I recommend DynaMat & DynaPad.

 

I don't know what the early posters were talking about saying the mat makes little or no difference. I used Fatmat Rattletrap on my 73 coup, which is 50 mil thick and the difference in heat and sound was huge! I used a 50 ft roll and covered the entire interior including the rear compartment. I'm really happy and, I guess that is all that matters.
Roozstr out

 

DUB,
Yup, doing it right, I believe dynapad is their version of mass loaded vinyl with the addition of foam to act as a isolator/disperser so actually you are using all three things just doing two at once with the dynapad.

Funny you should mention extremeliner has lead in it. Lead is the best material for this but its $$$ and heavy. I believe both Rolls-Royce and Maybach(when they were still around a few years ago) both used a layer of lead sheet in thier sound deadener. A audiophile friend of mine bought some lead sheet from McMaster Carr for one of his cars, stuff was pretty pricey.

 

You only need sound damping in the storage compartment. There is little heat that gets to that area (unless you are sitting still and idling for a long period of time).

The factory used "tar paper" (1/8" thick sheets of tar-impregnated cardboard) for sound deadening. It was reasonably effective. Most folks throw that stuff away when they redo the interior. That stuff is much less expensive than Dynamat.

The front floorboard areas and the firewall are the primary heat-absorbing areas in the car. Good heat insulating material there is a VERY good idea.

P.S. I thought that Dynamat was for sound deadening, only. It has a reflective barrier for radiat heat reflection, but it only slows the transfer of convection heat...it won't impede it.