"Sound Deadening"
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
If that stuff you got works, that is cheap indeed. The stuff i bought, being the bulk pack of DYNAmat Extreme, cost me $324 Australian, and it contains about 36 sq/ft. Which is enough to do what you see in my pics, and have a bit left over, but not much.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
True that price is really great if the stuf works.
I had several broken or cracked plastic trim pieces to repairing those is slowing the project as well as the "learning curve" of taking it all apart for the 1st time.
BTW, I guess you are in Spring heading for Summer down under. But is it a "dry heat"!
When I was working in Mesa, AZ I hated that term...it was just damn hot. 
I had several broken or cracked plastic trim pieces to repairing those is slowing the project as well as the "learning curve" of taking it all apart for the 1st time.
BTW, I guess you are in Spring heading for Summer down under. But is it a "dry heat"!
When I was working in Mesa, AZ I hated that term...it was just damn hot.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Originally Posted by 65Z01
True that price is really great if the stuf works.
I had several broken or cracked plastic trim pieces to repairing those is slowing the project as well as the "learning curve" of taking it all apart for the 1st time.
BTW, I guess you are in Spring heading for Summer down under. But is it a "dry heat"! When I was working in Mesa, AZ I hated that term...it was just damn hot.
I had several broken or cracked plastic trim pieces to repairing those is slowing the project as well as the "learning curve" of taking it all apart for the 1st time.
BTW, I guess you are in Spring heading for Summer down under. But is it a "dry heat"!
When I was working in Mesa, AZ I hated that term...it was just damn hot. Yeah mate, spring going into summer. We had 36'C (97'F)here today,and last year in the peak of summer we had alot of 40'C (104'F) days and highest i remember was 46'C (115'F) Not sure how that compares to Mesa, but its frigen hot!!! Just last week we had top temps of about 22-24'C (71.5-75'F) and night time lows were about 7-10'C (44.5-50'F) Big change in a short time.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
When in Mesa, AZ over a summer temps regularly got into the 115deg F range and never dropped below around 97deg F in the evening. The best part of that job was the day I left and drove my new '88 Vette home; within an hour of leaving the "Valley of the Sun" air temps had dropped to mid 60s and I had the heater on.
I've been plagued with a week of rain here in SE NY so progress has been painfully slow. But I have nearly all the rear carpet out and all the plastic trim pieces repaired. On some I just used Crazy Glue in the cracks; on others I've used my old standby of JB Quick Set with a thin piece of Al sheet.
I still need to pull the storage bin enclosure so I can access that area as I feel lots of noise comes in through those two large "echo chambers".
The cheapo material I'm going to use does not come with any adhesive as it's intended for another application. Since I too plan on several layers of the stuff I'm wondering what is a good adhesive to tack it down?? I do have a copla cans of spray undercoating that I believe Casethecorvetteman used and seems like it should work.
I've been plagued with a week of rain here in SE NY so progress has been painfully slow. But I have nearly all the rear carpet out and all the plastic trim pieces repaired. On some I just used Crazy Glue in the cracks; on others I've used my old standby of JB Quick Set with a thin piece of Al sheet.
I still need to pull the storage bin enclosure so I can access that area as I feel lots of noise comes in through those two large "echo chambers".
The cheapo material I'm going to use does not come with any adhesive as it's intended for another application. Since I too plan on several layers of the stuff I'm wondering what is a good adhesive to tack it down?? I do have a copla cans of spray undercoating that I believe Casethecorvetteman used and seems like it should work.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Originally Posted by 65Z01
When in Mesa, AZ over a summer temps regularly got into the 115deg F range and never dropped below around 97deg F in the evening. The best part of that job was the day I left and drove my new '88 Vette home; within an hour of leaving the "Valley of the Sun" air temps had dropped to mid 60s and I had the heater on.
I've been plagued with a week of rain here in SE NY so progress has been painfully slow. But I have nearly all the rear carpet out and all the plastic trim pieces repaired. On some I just used Crazy Glue in the cracks; on others I've used my old standby of JB Quick Set with a thin piece of Al sheet.
I still need to pull the storage bin enclosure so I can access that area as I feel lots of noise comes in through those two large "echo chambers".
The cheapo material I'm going to use does not come with any adhesive as it's intended for another application. Since I too plan on several layers of the stuff I'm wondering what is a good adhesive to tack it down?? I do have a copla cans of spray undercoating that I believe Casethecorvetteman used and seems like it should work.
I've been plagued with a week of rain here in SE NY so progress has been painfully slow. But I have nearly all the rear carpet out and all the plastic trim pieces repaired. On some I just used Crazy Glue in the cracks; on others I've used my old standby of JB Quick Set with a thin piece of Al sheet.
I still need to pull the storage bin enclosure so I can access that area as I feel lots of noise comes in through those two large "echo chambers".
The cheapo material I'm going to use does not come with any adhesive as it's intended for another application. Since I too plan on several layers of the stuff I'm wondering what is a good adhesive to tack it down?? I do have a copla cans of spray undercoating that I believe Casethecorvetteman used and seems like it should work.
The best thing i can think of to glue down your insulation is probably rubber cement type glue, or maybe even weather strip adhesive.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Thanks for the info; I'll pull the speaker enclosures and shoot some sound deanener ("muffel cloat") into that area to hopefully cut down on road noise from the rear tires.
Last time I was on rough worn concrete pavement the "road noise" was so intense that it drounded out the "resonance" from the pipes.
Looks like I should search for a good spray adhesive for the layers of deadening material.
BTW, I've noticed that with most of the plastic trim pieces out of the hatch area the number of "squeaks" is nearly nill now. That is a big clue as to how to eliminate em.
Last time I was on rough worn concrete pavement the "road noise" was so intense that it drounded out the "resonance" from the pipes.
Looks like I should search for a good spray adhesive for the layers of deadening material.
BTW, I've noticed that with most of the plastic trim pieces out of the hatch area the number of "squeaks" is nearly nill now. That is a big clue as to how to eliminate em.
Last edited by 65Z01; Oct 10, 2005 at 01:55 PM.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Originally Posted by 65Z01
Thanks for the info; I'll pull the speaker enclosures and shoot some sound deanener ("muffel cloat") into that area to hopefully cut down on road noise from the rear tires.
Last time I was on rough worn concrete pavement the "road noise" was so intense that it drounded out the "resonance" from the pipes.
Looks like I should search for a good spray adhesive for the layers of deadening material.
BTW, I've noticed that with most of the plastic trim pieces out of the hatch area the number of "squeaks" is nearly nill now. That is a big clue as to how to eliminate em.
Last time I was on rough worn concrete pavement the "road noise" was so intense that it drounded out the "resonance" from the pipes.
Looks like I should search for a good spray adhesive for the layers of deadening material.
BTW, I've noticed that with most of the plastic trim pieces out of the hatch area the number of "squeaks" is nearly nill now. That is a big clue as to how to eliminate em.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Well damn NY weather finally cut me a little break in the drizzel so I now have all the carpet, the plastic trim pieces, the bins and Bose speaker assys out of the hatch area.
Being curious as to just were the resonance is getting into the cabin I started the engine, listened, & felt around the fiberglass flooring ...voila..lay my hand on any area of the fiberglass panels in the hatch and I feel strong vibrations, but none from the vertical fiberglass panel just behind the seats. So the conclusion is:
-sound deadening material is needed on all the fiberglass surfaces in the hatch but not in the cabin proper
-gluing the material directly to the fibergalss works to change the natural frequency of the panels as well as dampen the sound at the source...the panels (they are acting like huge speakers).
Hmmm, could it be that 20-30Hz (1200-1800 RPM) is the natural frequency or our hatch floor or a major portion of it??? Would not this explain why resonance is not an issue in other Vettes (do C5 guys complain of it & if so, is it as severe as with C4s???).
If so the answer is not to chose an exhaust to minimize resonance, but rather to glue down a matt to change (as well as dampen) out that natural frequency.
Now I'm stoked to proceed and test my hypothesis.
Being curious as to just were the resonance is getting into the cabin I started the engine, listened, & felt around the fiberglass flooring ...voila..lay my hand on any area of the fiberglass panels in the hatch and I feel strong vibrations, but none from the vertical fiberglass panel just behind the seats. So the conclusion is:
-sound deadening material is needed on all the fiberglass surfaces in the hatch but not in the cabin proper
-gluing the material directly to the fibergalss works to change the natural frequency of the panels as well as dampen the sound at the source...the panels (they are acting like huge speakers).
Hmmm, could it be that 20-30Hz (1200-1800 RPM) is the natural frequency or our hatch floor or a major portion of it??? Would not this explain why resonance is not an issue in other Vettes (do C5 guys complain of it & if so, is it as severe as with C4s???).
If so the answer is not to chose an exhaust to minimize resonance, but rather to glue down a matt to change (as well as dampen) out that natural frequency.
Now I'm stoked to proceed and test my hypothesis.
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Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Originally Posted by 65Z01
Well damn NY weather finally cut me a little break in the drizzel so I now have all the carpet, the plastic trim pieces, the bins and Bose speaker assys out of the hatch area.
Being curious as to just were the resonance is getting into the cabin I started the engine, listened, & felt around the fiberglass flooring ...voila..lay my hand on any area of the fiberglass panels in the hatch and I feel strong vibrations, but none from the vertical fiberglass panel just behind the seats. So the conclusion is:
-sound deadening material is needed on all the fiberglass surfaces in the hatch but not in the cabin proper
-gluing the material directly to the fibergalss works to change the natural frequency of the panels as well as dampen the sound at the source...the panels (they are acting like huge speakers).
Hmmm, could it be that 20-30Hz (1200-1800 RPM) is the natural frequency or our hatch floor or a major portion of it??? Would not this explain why resonance is not an issue in other Vettes (do C5 guys complain of it & if so, is it as severe as with C4s???).
If so the answer is not to chose an exhaust to minimize resonance, but rather to glue down a matt to change (as well as dampen) out that natural frequency.
Now I'm stoked to proceed and test my hypothesis.
Being curious as to just were the resonance is getting into the cabin I started the engine, listened, & felt around the fiberglass flooring ...voila..lay my hand on any area of the fiberglass panels in the hatch and I feel strong vibrations, but none from the vertical fiberglass panel just behind the seats. So the conclusion is:
-sound deadening material is needed on all the fiberglass surfaces in the hatch but not in the cabin proper
-gluing the material directly to the fibergalss works to change the natural frequency of the panels as well as dampen the sound at the source...the panels (they are acting like huge speakers).
Hmmm, could it be that 20-30Hz (1200-1800 RPM) is the natural frequency or our hatch floor or a major portion of it??? Would not this explain why resonance is not an issue in other Vettes (do C5 guys complain of it & if so, is it as severe as with C4s???).
If so the answer is not to chose an exhaust to minimize resonance, but rather to glue down a matt to change (as well as dampen) out that natural frequency.
Now I'm stoked to proceed and test my hypothesis.
with you and from experience even more.My 87 had a horrifiying resonance that i got rid of almost indefinatly with some cheap sticky backed foam deadener. The 94 is more a case of lots of road noise and sqweaky rattles,all of which are gone from the areas completed!!
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Looks like i might have to put off the interior removal for a little while, i went to the doctor today,thinking i had a hernia, turns out i have 2 of them!! 1 of them is starting to get abit sore at times. (very weird feeling) But make sure you keep posting where youre at 65Z01(and others!), im interested to see how your car turns out. Send me an email if you like. 
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Sorry to hear of your misfortune; hope you are on the mend soon.
Today I picked up some 3M spray adhesive at Lowe's and am very anxious to get to it...except for this neverending rain. If my (above) hypothesis is right the sound deadening will be most effective is glued tightly to the panels in the hatch.
BTW, with all the material removed from the hatch, I took her out this morning in heavy rain...what a difference. With no carpet at all it sounded like there rear wheel wells were open to the street.
Today I picked up some 3M spray adhesive at Lowe's and am very anxious to get to it...except for this neverending rain. If my (above) hypothesis is right the sound deadening will be most effective is glued tightly to the panels in the hatch.
BTW, with all the material removed from the hatch, I took her out this morning in heavy rain...what a difference. With no carpet at all it sounded like there rear wheel wells were open to the street.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Originally Posted by 65Z01
Sorry to hear of your misfortune; hope you are on the mend soon.
Today I picked up some 3M spray adhesive at Lowe's and am very anxious to get to it...except for this neverending rain. If my (above) hypothesis is right the sound deadening will be most effective is glued tightly to the panels in the hatch.
BTW, with all the material removed from the hatch, I took her out this morning in heavy rain...what a difference. With no carpet at all it sounded like there rear wheel wells were open to the street.
Today I picked up some 3M spray adhesive at Lowe's and am very anxious to get to it...except for this neverending rain. If my (above) hypothesis is right the sound deadening will be most effective is glued tightly to the panels in the hatch.
BTW, with all the material removed from the hatch, I took her out this morning in heavy rain...what a difference. With no carpet at all it sounded like there rear wheel wells were open to the street.
Yeah mate, feeling a little sore after a long day at work, dont know how long ill keep that up!! Im very keen to hear how that stuff you got turns out, its gotta have some effect at the very least!!
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Finally got a day w/o damn rain; got the cheapo sound deadening installed. I don't think it has helped much, but I came across an interesting phenomenon.
I did a little brake stand up to 1,400rpm and the drone was LOUD. I ran my hand across the rear matting and could still feel muted vibrations. But, when I pressed my hand against the outside of the RH well (where the storage bin would go), the drone dropped substantially. I also noticed that the walls of that well were vibrating far more than the hatch floor.
Tomorrow I'm out to the hardware in search of a brace to unstall between the inner & outer well sides to see if that will stop the severe drone during a brake stand. I'm pretty sure this vibration is what casuses the really bad resonance at that RPM under light load.
I did a little brake stand up to 1,400rpm and the drone was LOUD. I ran my hand across the rear matting and could still feel muted vibrations. But, when I pressed my hand against the outside of the RH well (where the storage bin would go), the drone dropped substantially. I also noticed that the walls of that well were vibrating far more than the hatch floor.
Tomorrow I'm out to the hardware in search of a brace to unstall between the inner & outer well sides to see if that will stop the severe drone during a brake stand. I'm pretty sure this vibration is what casuses the really bad resonance at that RPM under light load.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Originally Posted by 65Z01
Finally got a day w/o damn rain; got the cheapo sound deadening installed. I don't think it has helped much, but I came across an interesting phenomenon.
I did a little brake stand up to 1,400rpm and the drone was LOUD. I ran my hand across the rear matting and could still feel muted vibrations. But, when I pressed my hand against the outside of the RH well (where the storage bin would go), the drone dropped substantially. I also noticed that the walls of that well were vibrating far more than the hatch floor.
Tomorrow I'm out to the hardware in search of a brace to unstall between the inner & outer well sides to see if that will stop the severe drone during a brake stand. I'm pretty sure this vibration is what casuses the really bad resonance at that RPM under light load.
I did a little brake stand up to 1,400rpm and the drone was LOUD. I ran my hand across the rear matting and could still feel muted vibrations. But, when I pressed my hand against the outside of the RH well (where the storage bin would go), the drone dropped substantially. I also noticed that the walls of that well were vibrating far more than the hatch floor.
Tomorrow I'm out to the hardware in search of a brace to unstall between the inner & outer well sides to see if that will stop the severe drone during a brake stand. I'm pretty sure this vibration is what casuses the really bad resonance at that RPM under light load.
Get some of that dynamat like i have, it will add rigidity to the panels and that will stop that noise.It worked in the back of my car quite well.
Last edited by Casethecorvetteman; Oct 16, 2005 at 01:48 AM.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 66
From: Queensland, AUSTRALIA
Originally Posted by 65Z01
Well I'm too cheap and I always loved "Megiver" so will try the brace in the well trick.
If that fails I'll have to shell out for the Dynamat.
If that fails I'll have to shell out for the Dynamat.
Give the Pheonex foundation a call mate, they might have the stuff you need to make a Macgyver type modification!!! Jesus thats going back a few years!!