? about DYNAMAT

[ss dave]

i just found this from Casacade Audio Engineering: VB-2 & VB-2HD twice the damping and 1/2 the wt. of asphalt materials(fat-mat). It has stick adhesive backing. They also offer V-Max, a aluminum layer, non-curing butylene rubber pad. Also found VE-1 vinyl sheets for twice damping effect with a leather grain look for those visible areas. i found this stuff after applying my fat mat and looking for speaker boxes.

[Tom Welch]

Ok, here goes nuthin' I have found some interesting info on sound insulation. It goes like this. In order to stop sound from coming into the cabin of a vehicle there are a couple of options for effective insulation. First, insulate the firewall from the engine compartment side. This is the correct way to do this. A foil facing with 1/4" foam then a noise barrier (solid layer 1/8" thick, like hard rubber) then about 3/4" sound absorbing foam, this is 1 effective way to seriuosly dampen interior noise. Another is to start with reinforced foil facing on the noise barrier which covers 1" of sound absorbing foam. This looks real good, would make a really neat firewall. The second option is to insulate from the inside starting with some vibration damper. I dont recommend covering the whole car with this type of product, just about half of the interior, evenly spaced pieces, works just as good. Less expensive, too. Aluminum faced high temp foam with or without a psa works very well here. On the under side of the body in strategic areas apply a heat shield, aluminum faced fiberglass or silica matting. Also nonwoven material in the form of fiberglass or silica with 9 micron sized fibers, (non-respirable) can be used inside the cab to insulate effectively against heat provided that aluminum is on both sides of the mat. I have read several articles about how some rod shops do this. They follow the looks is better than function school. It seems like that anyway. Using Lizardskin first then a heatshield and then foil covered jute is just plain wasteful. The Lizardskin dampens vibration, put this on the inside of the car first, then the foil covered jute. Put the heatshield where it will do something. on the firewall or under the floor between the floor and exhaust. Logic works, looks are fine but performance trumps looks anyday, especially after the upholstery is in place. In order to have a nice smoothed firewall, care must be taken to avoid ineffective insulation application. Most insulation for sound deadening is made to go in the engine compartment area, hence the aluminum facing for heat reflection. The foam absorbs sound waves, the sound blocker does just that, blocks sound waves, reflecting them back at the source. Put on backward it does almost nothing. The products used inside the cab have a different composition and a layered approach is needed. This is what most people already do, but with incorrect products for the application. Foam works inside the cab very well if made for the interior of a vehicle, carpeting over the foam, fiberglass, jute, whatever, adds a little more. One thing I have found to be true for me. A quiet car isn't hot and a noisy car isnt cool. I recommend an aluminum facing for durability and to keep moisture out. I believe the best way to thermally and acoustically insulate a car is to use a heat shield on the firewall and above the exhaust, then vibration damper on the interior floor and doors and other areas of vibration. Topped with a heat resistant foam about an inch thick with a foil facing. This should prove effective for most applications. Double the foam on the firewall interior if needed to absorb the noise. More to come.

[Jagarang]

Finally, some information that sounds reasonable without allot of "marketing" hype and mumbo jumbo. The insulation on the engine side of the firewall will likely be a wash with most of our cars, we try to make the firewalls look to pretty to cover them with a foil/foam insulator. In inner side information is intriguing indeed. One of my concerns is thickness of the material overall, and interference with various structures. 2 inches sounds like allot of room to squeeze out of an area that's already tight. It seems like its time to take another look at things under the dash to refresh my memory.

Tom...
When you mention, "covering about half of the interior with strategically placed pieces", I assume this would mean an X by Y sized square in the middle of a panel. Any idea yet what sized piece or approximately what ratio of applied product to surface area might be most effective? Is it as simple as covering 50% of the available surface area/panel? As we all know this stuff can get "heavy" and the possibility of not having to cover every inch of the interior with it could potentially save ALOT of poundage, not to mention the cost factor; which you have already mentioned. Foam sounds "lighter", both on the pocket and in the car, than the other materials currently available, as long as we can fit it where it needs to go.

Are you still thinking of offering a "kit" form of these types of products, and any prospectus on when they might become available?

[Tom Welch]

Jagarang, you are right about the firewall issue. The outside will be detailed and the space on the inside will be limited. All of this is a study in compromise anyway. As for the vibration damper if you measure a section of floor, say the pass side front footwell. For example lets say 24"x24" half of this area is 12"x12". put this as close as possible to the center of the panel measured. That should do it. The flatter and smoother a panel is the more it will tend to vibrate. The stiffening ribs that are seen in the floor of your car lessen the vibration of the panel at certain frequencies. This is a good thing. The vibration damper that you add will absorb some of the vibration and convert it to heat. Not noticeable. The foam works great but there are drawbacks, too. Foam that is open celled will absorb water and become useless until dry, just like most insulation will. The exception to this is natural wool fibers. I dont see wool becoming the next big insulator for cars, besides, it won't stop sound. The firewall is the biggest area of concern for noise supression. Foam here would probably work very well when sealed properly. Foam is sometimes lighter on the pocket, but not always. Not always lighter in weight either. I have experimented with quite a few foams and durability under carpet is the biggest issue I have found. For the roof and package tray and firewall it is ideal. The doors too. The floor is another thing. Still working on this one. The best solution yet is heat shield under the floor, vibration damper on the inside of the floor, followed by a foil/mylar covered material yet to be determined. Maybe, inspite of what I said yesterday jute type material may be the best compromise for this area. Still working details on the kit.

[ss dave]

OK, thanks Tom. Personal and recent experience. I have a 69 Camaro convrt. just redid the interior. I placed Fat mat over the entire floorboard, except on top of the console area, then tripple jute pad on the footfall areas. Fat mat on the inner door skins and door panels, this made the doors "thunk" when shut, they sound solid and heavy. Fat mat on the panels inside the kickers and the entire trunk along with a layer of jute and carpet. Didn't have any issues with shipping(except a UPS mistake) or smell, app. was easy. As mentioned above there maybe better products and you may use less material but the bottom line is it made a world of difference! even in a vert. No squeaks, rattles. I'm pleased with the outcome.

[Jagarang]

One of my concerns with the doors and using Fat Mat/Dynamat Etc. is that the hinges already hate life with just the door's weight. This eventually affects function and body gaps. The less weight I can put in there, the better.

[ss dave]

I agree. I made sure my door wedges are functional, keep the hinges well lubed and maintained. Overall added weight to the doors with fat mat was approx. 1.6#, i believe this is but a fraction of the entire door weight. I know what you are saying however, since I replaced a worn drivers door hinge on my 98 Tahoe. But with that in mind: I love the sound of the door when it shuts! It gives the car a solid sound that exudes a "well built" quaility , a new car feel and sound.

[blackbeast]

here's what i did about 2 years ago when i redid the interior on my S-10 blazer. Imagine a box on wheels vibrating with a 350 and 2.5 dual dynomax mufflers.

I too couldn't afford, and didn't want to pay for dynamat, way too expensive, and i knew there had to be a better alternative.
anyways, b-quiet used to offer a roll on plastic type deadner that seemed to satisfy vibration dampening. i rolled on about 2 coats of that and then added insulating foam with a aluminum heat liner from i believe Jc Whitney of all places ( i think it was 3/8 in thick) I also added another layer of factory sound deadning from a donor blazer and then new carpet. Since I had the dash out, i used the B-quiet rollon stuff, and a layer of dynamat b/c there was no room for anything else.

The difference was quite amazing, and this thing is dead quite cruising down the freeway 70mph, 1,100 RPM. I was told by a sound-guru friend that coating the cieling would also add a great deal to vibration dampening but the pain of pulling down the headliner again stopped me from doing that.

summary:
I spent around $70-90 and was able to significantly reduce sound (especially exhaust drone) on and S-10 blazer, which i would think would be much more difficult than the average muscle car.

[Tom Welch]

I did some testing today and the results are interesting. I evaluated some heat shielding that was a peel and stick product advertised to be effective to 1000 degrees. It was tested with direct and indirect heat once placed upon a metal panel. This was the most scientific of tests. My stove, a piece of sheet metal, some peel-n-stick vibration damper and 2 other insulation products for a layered approach just for fun. The direct heat test got up to about 500 degrees. Almost no 'shielding' was noticed. Indirect testing had similar results. The peel-n-stick vibration damper butyl rubber melted and made a sticky mess. The other insulation products did provide some positive results. I tested a nonwoven insulation fabric with aluminum facing that was about 3/8" thick and, a foam insulation with aluminum facing that is about 1" thick. The nonwoven fabric became fairly warm to the touch but was not uncomfortable at all. The foam became slightly warm and was obviously much better at insulating against heat. As for the heat shield it delaminated and began turning black. These test results were done under controlled conditions and the theory that if it burns me its too hot was the standard I used. I did this in my kitchen on my stove. The temps hovered around 500 degrees. The foam will under go some more testing in Dexter's Lab. I will be testing for durability. I have tested for water retention already and both the nonwoven material and the foam failed miserably. Both products absorb water like the thirst a guy running across the desert with his mouth open would have. However, if the foam can be sealed this may not be an issue. More samples of products are coming in and testing continues. It appears that this endeavor may take longer than I predicted. On we go...

[69Rathead]

Tom...Thanks for all the great info on your last few posts...definitely getting interesting! The testing sounds funny but it seems to me it will be effective. Looking forward to seeing what results you come up with.

[Tom Welch]

Thanks Rathead, testing is funny and fun, I received a heat pad yesterday that will work, its made of ceramic powder, kind of like space shuttle tiles. Yep, it works. But will be heavy and expensive. But man it stops heat like no other. Not much for vibration damping or sound, though. I need to call these guys about some thinner stuff. They are called Thermodyne. I think their Excelflex product will work good for heat shielding. It will lower temps alot, for example- if the hot side is 1800 degrees the cold side will be 250 degrees. Talk about effective.

[Tom Welch]

hey eb'body,
I need some info from other than myself and local folks. What temps do you see on an uninsulated area of your firewall and floor? I'm trying to assemble an average temp to work with. I have material that will work well beynd 500 degrees but I dont think that very many will need that sort of range. I think that 300 degrees will probably be the upper limit of the temp range that I will be woking with. Check out solimide foam, give me an opinion about it, please.

[Tom Welch]

Ok, so no opinions on solimide. No problem, I have decided against it for cost reasons. Melamine foam works as good and is a lot less expensive, too. Recently ran across a headliner foam that has a perforated vinyl skin that closely matched the headliner material from early 2nd gen f-bodies. It works great, had my 67 shell in the sun to test some material and the headliner foam definitely does the job. Best of all its 1 product that can insulate and finish the interior roof area. Its made by dB engineering.

[USAZR1]

Just curious but has anyone have any experience with the spray-on bedliner material? I've been hearing some of the streetrod guys are having their interiors and undercarriages shot with this stuff. It's not very thick so you could add jute padding and carpeting over the top of it. What are your opinions about its effectiveness inside a car?

[third base]

I did Mortons spray on bed liner on my 69' camaro. I did the trunk, underbody, and floorboards. I am still going to use Dynamat though. If I were to do it over again i would have saved up more money and had it done in Line-x. Much more thicker and more durable. The Mortons does look really good on the underbody though.

Question for Tom...should I still do the floorboards in Dynamat over the bedliner? I want do the roof, firewall, doors, and behind trim panels and need to know if I should order more. the metal is sandwhiched on the floorboards with Mortons bed liner as of now. Thanks

[Tom Welch]

If you have both sides covered in the bed liner, I dont believe that Dynamat or anything else will improve on what you have. The vibration damper wont do much unless it is in direct contact with the sheet metal. I havent tested any of the spray on stuff so I'm taking a guess here. The questions I have about the bedliner that I havent much info on is what temp will it withstand on a continuous basis. Also how much does it weigh once cured? What thickness is needed for good vibration damping? Is it the same as the spray on damper? I have decided not to use this for vibration damping since it will be difficult to regulate the thickness when spraying. The peel and stick damper will be a better choice in the event of body damage to doors, fenders, etc.

[third base]

Thanks, that is what I thought. I asked the temp. question to Mortons and they said that it would withstand 350+ degrees. I hope they are right because I will be firing it within the next month.

Next question, I was thinking of using Dynamat's Tac Mat for sound dampening. I want my car to sound like a new luxury vehicle (when I have the windows down) as I drive down the freeway. Is there something cheaper (foam)that I can get that does just as good as job if not better. And where should I put it. Maybe me interior guy can get it for me??? what do you think?

As for the bed liner it is pretty light, urethane based, and pretty easy to shoot and get the proper thickness. I have used dynamat's spray and it is very brittle. I think it sucks! Mortons is much better. My painter also does alot of fiberglass bodied cobras and he uses the same product (mortons) to stiffen up the bodies so I think it should be a great vibration dampener. not as cheap as peel n' seal though. about 200 bucks in bed liner for the underbody of my camaro. 400 when you add the floorboards and trunk.

[Tom Welch]

I would suggest acoustical foam for the firewall and inside the doors as well as the roof. for the floor a high density foam will work pretty good. Melamine for the firewall since it doesnt burn. Also the underside of the hood can be insulated with a foil faced foam that will do alot for quieting the cars interior. If you need help finding this stuff let me know. As for the spray on damper, if you use it somewhere besides the floor I suggest only the roof area. If you ever get dents in your doors/quarters you will regret the spray on stuff. The peel and stick damper That is a high density product unlike all of the commonly used stuff is best here. It will dramatically reduce resonance of the panels it is attached to and will pull away without the mess of spray on or Dynamat type dampers.

[third base]

i am using Dynamat extreme on doors and roof. Is roof ok to put dynamat on? and any other trim panels. where can I get the foam needed? How much is this going to cost me?

[USAZR1]

Tom,would it be possible for you to post some links or photos of some of this stuff you're recommending?