okay, we all had this talk at the FFC. Some people love it, and some people didn't think it worked.....

does it really work or not....and where can i get cheaper stuff than the expensive dynamat branded stuff...this is down the road a bit.

b

Maybe this?

On the inside right?

I have been wondering myself about this and was going to do search but since you started a thread.....

QUOTE (Headrage @ Nov 1 2005, 09:27 PM)

Maybe this?

yeah...kinda like that.

me and the search function don't get along very well.


b

sound waves can be blocked pretty well with two different materials.

The idea is that the first material blocks out a specific set of sound waves, the next material blocks the other sound waves.

It cannot be two layers of the same material, that would still only block a certain set of sound waves...

Try rubber roofing, and 18 inch flooring pad (the stuff for under the pre-engineered wood floors)

Both are available at Home Depot and you can test it out.

We have used the rubber Ice and water Shield layed over lead to block out sounds to special offices etc...

We have used two differing types of foam ,

The idea is two different materials, two unique molecular structures...

good luck,

Rich

I used Dynamat on boty sides of my firewall. It's held up great for 3 years. Peel and stick. I used the end of a large screw driver handle to work the mat into the contours of the firewall. It works good I guess but I haven't had anything to compare it with.
Elliot

r-Towle said it perfectly.

Ask a dozen differant sound engineers. And you will get a dozen differant solutions.

So once upon a time in Car stereo competition... Long time ago......... To kill road noise.... Hmmm... Memory..memory.. Oh yeah.... Here it is......In my head.......

My mix is the following.

1:)One layer of BLUE plastic (Looks like rubber tarp) tile underlayment that you can buy at Home depot. This is used to waterproof a shower and typically is used over green board. Feels like very thick rubberized plastic sheeting.
Spray glue it down with Scotch 77 spray adhesive in the rattle can. or the heavy duty spray glue of your choice.

2:) Add one layer of 3/16th - 3/8ths or thicker of neoprene rubber. It's just like wet suit material.
This stuff has lotsa little air bubbles trapped tha really deaden sound. And it's light. The closer (smaller) cell neoprene you get. The better it works. And the more it weighs. Get what you are comforatble with.
If you have the room. Thicker is better. Install neoprene over the Blue plastic. Spray glue down with Scotch 77 in rattle can. Your DONE

OR:

3:) If ya want to over kill it. Instead of the Blue plastic. Go to a roofing supply house and ask them for TORCH DOWN ROOFING MATERIAL with no sand. Sometimes comes in a roll with a thin sheet plastic stuck to one side. Sometimes no plastic stuck to one side. This stuff is very thick like 1/8th or thicker.

This is NOT rolled roofing like what you see on roofs. This goes UNDER the roofing you can see on roofs.
And no it isn't the thin felt paper you are used to seeing under the top of the roofs...
I.E. tar paper... NOPE... That ain't it eaither.

This stuff is TORCH DOWN.. Heavy shit... And it is an EXCELLENT but heavy sound deadning material in it's own right. Better than dynomat. And a bunch cheaper.
If plastic on one side... Remove plastic (if you can).(NOTE: This side goes down)

This is basicly a pure rubber and asphalt combination that is waterproof and last dam near forever. it is really dnomat on steroids. And you can put layer over layer.

I have doen door pannels. Fire walls trunks.. you name it. it's been done.

NEVER OVER anything that gets 190 degrees or hotter. It will smell. So not on floor boards of a single exhaust big block chevy ytruck with a gunked up Catalyitic converter. Makes the floor smoke. Ask me how I know...Please......

Teeners = no probs....

You can apply it with a torch or a heat gun. You get it so hot it melts onto whatever surface you put it on. NO GLUE NEEDED if ya torch it on.....

Can also be glued on with any kind of panel adhesive or flooring adhesive. ONLY use water based adhesive if you are using flooring adhesive. Test your glue on a spot on the material for adhesive quality's BEFORE USING!!!!!!

Ya don't need the vapors of a petoleum based glue in your car for weeks. USE WATER BASE if your gunna use flooring or panel adhesive... he says again.....

The trick here is to use two or more differant kinds of materials to mitigate the resonance of the ambient sound freqs. and engine sound waves. The more dissimilar materials you use that will work in this application and knock out the lower freqs. The better you are...

Cause each material damps out differant freqs. The material I mentioned above is dam good based on the end results you are looking for.

Really knocks down 1st, 2nd, 3rd, 4th, etc. harmonics down to a pleasant level.

Wheres a MLSA waterfall plot when you need one??????

That said... There is some aircraft sound deadning material that is freakishly good. Cept it's made for a differant harmonic and freq. than what we need..(Me Thinks)

Find a metal trash can lid or a good size piece of sheet metal. Glue some stuff on it.. hit it with a stick or a hammer before and after... you will get the idea of what works......

NEVER USE THIS COMBO OR ANY SINGLE PART OF THIS IN THE ENGINE BAY..

IT AINT HEAT I AM TOO WORRIED ABOUT. (but it's a thought)
IT'S THE PROBLEM OF TRAPPING MOISTURE TO THE FIREWALL

Thats my 0.02 worth.

Twystd1

PS: dont be in this car when it is burning... Makes for a hell of cough

I conversed with a neoprene guy i found on ebay for under carpet and firewall mat. He seemed to think it would work well. It seemed cheap, but I never got around to ordering any. Also, I forget if I was going to mount in the engine bay or the cabin.

Thought I'd throw out some food for thought.

I used a bit of that aluminium-backed carpeting insulation in my cab on the firewall (1" thick) and floorboards, it killed a lot of the noise. After doing so I realized I'd have to rip sections of it out to do an Engman Long Stiffening Kit. So I'll order more, and I just recently purchased a large 48" x 80" roll of Neoprene insulation for $20 shipped. This gives me plenty of material for the whole car (trunks, hoods, doors, cab, etc). Combined with asphalt-rubber based insulation in the engine bay, I think I can cut the in-cab and car/road noise down considerably. Hell, just adding insulation to the f/g top removed a lot of it. Unfortunately the glue I used was crap and a few days with the heat of the sun beating down on the top it all fell off. I'll re-try with the Neoprene which should be lighter as well. Neoprene is waterproof too, I think.

Didn't somebody post a link to some paint on latex based sound insulation? That's what I want to do, but I've been waiting for someone else to be the guinea pig.

You mean Rhino Liner? The stuff that makes brick-walls bulletproof to a 30-06?

Rhino liner is VERY HEAVY...

If ya find the right guy with the right spray gun... And the right pump.
You can mix a 30/50 potion of rhino liner and vermiculite...

30 V + 70 R

it's reasonably light and stops sound dead....

Blew up two gun tips and one pump till I had it figured right.

Then again...it wasn't my equipment. We only did it as a test for a pump company.

Worked trick......

Used the same paint pump the pro's use for spraying Tex-Cote.

Could duplicate...... Give it a try if ya got the connects...


NOW: For your entertainment......

Brando, I have to take you shooting some time to see what 178 grain match hand loaded 300 Win Mag will do to a brick.....
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.
.
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At a thousand meters.

Twystd1

As if I hadn't beat this horse to death..........

I always have a fear of applying anything to the engine side of the firewall.

Simply because it may catch and hold moisture and crreate a enviroment for MORE RUST.

I know I could make some homogenous, sealed, rubberized covering work.

And I know I could use the simple foil backed carpet pad kind of insulation which I KNOW will retain moisture.

Therefore I will be using nothing on th engine side. Because my car is a weekend warrior (when finished) (if finished) (Fuck whenever completed) (whatever)

On a street car without back pad. I like the neoprene/torch down scenario.
On a street car with back pad. Try the torch down only first. And see how ya like it.
On a street car that sees no water. Skys the limit. No water.. No rust....
On Aarons car... NADA. It's too ugly to make it sound less than a sardine can.....

There I go again...thinking I know something...........

Twystd1

cool!

thanks for the replies.


b

Clayton, we definitely gotta go shooting. Angolina flats is open during the non-brush-fire hazard season (spring) and you just need a trail pass for the day, some beers and a skeet launcher.

PS: I tried 210 grain in my M44 once (7.62x54R). Good old fashioned WWII rifle was blowing chunks through ½" I-Beam steel all afternoon. Damn was my shoulder sore

QUOTE (Brando @ Nov 1 2005, 09:46 PM)

So I'll order more, and I just recently purchased a large 48" x 80" roll of Neoprene insulation for $20 shipped.

Brando,

Can you give a name and number for your neoprene sheet source? Thanks.

I stripped out the old engine sound pad and refinished the firewall, so I expect a noise level increase.

I put the Dynamat Extreme on the firewall of both 914s. Betty's car did not have any sound or heat insulation in it when I started. It was fairly loud and really warm on the firewall, even with the back pad.

I put the Dynamat Extreme in and it dropped both the sound level AND The heat in the passenger compartment.

I put Dynamat Extreme in my car on the firewall, and put dynamat in the rest of the interior. It doesn't rattle at all now.

How much more does it weigh?

I am leary of adding weight to my car. Especially now that I have it all stripped down.

Zach

The total weight for the roll was about 5 or 6 pounds. I didnt' weigh it to get an exact weight. I was not too concerned about it. Both of our cars are supposed to be daily drivers first, and AX cars second. Things like insulation and Air Conditioning are necessary for a car that is driven to work every day.


BTW.. I drove my car to work today.... again!

I HAVE to get some sun visors installed in it!!! :blind:

QUOTE (Brando @ Nov 1 2005, 10:57 PM)

You mean Rhino Liner? The stuff that makes brick-walls bulletproof to a 30-06?

No, this stuff was marketed specifically as a sound insulation. It was blue.

QUOTE (maf914 @ Nov 2 2005, 06:17 AM)

QUOTE (Brando @ Nov 1 2005, 09:46 PM) So I'll order more, and I just recently purchased a large 48" x 80" roll of Neoprene insulation for $20 shipped. Brando, Can you give a name and number for your neoprene sheet source? Thanks. I stripped out the old engine sound pad and refinished the firewall, so I expect a noise level increase.

ebay. Seller was fuseguy224. He misspelled neoprene (nuprene).

The last restoration I did, I left the firewall clean and painted...Sure looked good, but you couldn't hear yourself fart inside with the plain ole' 2.0 wound up...

The problem is the engine reverberation (echo) along with the normal engine noise and heat...

I am dancing with this topic as we speak...4th Restoration now in progress, My firewall is now clean, huge rust-thru repairs welded in and soon to be painted...

I have come up with an idea...Not for the concours crowd...

DO NOT glue anything on the clean firewall or the proccess will just start again...

The problem is that any mat or product glued to the wall will hold/trap water and the rust will start over again...OK so why not mount the mat 1/4, 3/8, 1/2 inch off the firewall so the water will cascade down and run out over the newly POR'd and painted engine shelf drains...It's not just rain or snow etc., but you do plan to wash the new paint someday huh ???

Home Depot, Lowes etc. sell plastic spacers of several sizes and lengths...Mount the mat of choice on plexiglas(or any product that is impervious to water, your choice of thickness depending on weight to be supported)...

Here comes the squemish part...Drill appropriately spaced holes into the firewall and install 10/32 screws of appropriate length thru from the inside with a locknut on the firewall side (a drop of silicone in each hole and wipe off excess)...Side spacer over remaining screw shaft in the engine compartment...Install mat assembly on top of spacers and put a locking nut on the engine side...

Now the water etc. will drain down the back side behind the mat assembly without being trapped or absorbed...

Holes in the firewall for screws is a small price to pay for no more rust and quieter cockpit...

Just one solution...Maybe not for everyone...

2-OH!

QUOTE (2-OH! @ Nov 2 2005, 02:01 PM)

...........a bunch of stuff

I was thinking of also covering the sheetmetal where the relay board and the batter is as well as the rear trunk wall that is up against the engine compartment.....

crazy idea ???

Mike:

I was thinking about that myself...I just don't know that the benefit would be worth it...

2-OH!