[::CMS::]

Originally Posted by DerAlte

Instead, not extra. Boot lid doesn't radiate much induced road noise, but contributes to rattles from loose cables / wires and number plate rattling. One doesn't need damping sheets here - just stuffed cotton waste / closed-cell foam in enough.

In case of Duster, the boot bare metal was resonating and it got reduced a lot with damping

Moreover I have been using the tar felts for more than 2 years and tried all the possibilities by parking in direct sunlight and never had any smell issue.

[DerAlte]

Originally Posted by ::CMS::

In case of Duster, the boot bare metal was resonating and it got reduced a lot with damping ...

Stuffing virgin cotton waste / rolled up closed-cell foam in the empty space in the boot lid is also valid effective damping, albeit a very cheap alternative used by most installers.

Originally Posted by ::CMS::

Moreover I have been using the tar felts for more than 2 years and tried all the possibilities by parking in direct sunlight and never had any smell issue.

Nice, good for you. Others have had not-so-enchanting experience, perhaps something to do with the quality of tar-felt.

[::CMS::]

Originally Posted by DerAlte

Stuffing virgin cotton waste / rolled up closed-cell foam in the empty space in the boot lid is also valid effective damping, albeit a very cheap alternative used by most installers.

Nice, good for you. Others have had not-so-enchanting experience, perhaps something to do with the quality of tar-felt.

Before buying the felt I got sample pieces from many shops and tried all these possibilities. As per the dealer if you ask for roof waterproofing, you will get the correct one and there is only one type available for that purpose. BTW, SunnyBoi also has used the same one as mine, even the brand too and that one is available almost all the shops in SP road. Even if you get a different brand, if the felt is for waterproofing its nothing but tar and will not have any smell issue.

The bare metal floor and other parts cannot be stuffed with anything except the frames, but the rumbling or the resonating sound comes from the bare metal surfaces. Damping is the only possible way to reduce that.

[DerAlte]

Originally Posted by ::CMS::

... As per the dealer if you ask for roof waterproofing, you will get the correct one and there is only one type available for that purpose. ... even the brand too and that one is available almost all the shops in SP road. ...

Thanks, that's good information. Which brand?

Originally Posted by ::CMS::

...The bare metal floor and other parts cannot be stuffed with anything except the frames, but the rumbling or the resonating sound comes from the bare metal surfaces. Damping is the only possible way to reduce that.

@wishnipon was asking about boot lid / hatch. Yes, on flat single surface like floor - either felt carpet or better stick-on damping sheet is needed. The substantial boot floor in my Safari doesn't resonate because of the felt carpet, sub box and a lot of other stuff that stays in the boot.

Edit: Just saw @SunnyBoi's pic. That is a polymer-tar mix just like conventional damping sheets and doesn't stink. Conventional Tar Felt is tar mixed with mica powder with jute cloth backing.

[condor]

I have tried some tar sheet on the floor of my A-Star. So far, so good. After putting in the tar sheet, had left the car un-used for 2+ weeks. There was no smell. I am thinking of getting some more and damp the doors also.

Originally Posted by DerAlte

The substantial boot floor in my Safari doesn't resonate because of the felt carpet, sub box and a lot of other stuff that stays in the boot.

The floor of the Safari should have already a fairly thick damping sheet.

[::CMS::]

Originally Posted by DerAlte

Thanks, that's good information. Which brand?

@wishnipon was asking about boot lid / hatch. Yes, on flat single surface like floor - either felt carpet or better stick-on damping sheet is needed. The substantial boot floor in my Safari doesn't resonate because of the felt carpet, sub box and a lot of other stuff that stays in the boot.

Edit: Just saw @SunnyBoi's pic. That is a polymer-tar mix just like conventional damping sheets and doesn't stink. Conventional Tar Felt is tar mixed with mica powder with jute cloth backing.

As per the dealer now a days only these kind of tar felts are available for roofing, older one which is tar with mica or fine sand pressed (very difficult to handle too) is very rare and all the samples I got are of same type, few from other brands too dont remember the name (mine was written IWL Plasticfelt, hope thats the brand name). Also for fixing at some places I have used pure tar too (available in 1kg tins).
Duster's boot has carpet and a subwoofer too, but it resonates \ makes a rumbling sound.
Also damping at wheel wells reduces the tyre noise to a great extend, will be damping the plastic shield in the wheel well too.

[::CMS::]

contd..

Carpets wont prevent a surface from resonating unless its pasted.
Also for proper damping, we dont have to cover the whole area, a 70-80% is enough, however first layer with smaller overlapping layers is the key.
To those who are planning to use tar felts, make sure that you remove the transparent plastic layer at the backside of the felt to expose the tar (the most time consuming and difficult part in this DIY), else the felt will comeout easily and wont serve the purpose. Even if you use any glue like SR or melted tar, this layer will be separated leaving the other layer on the metal surface. Exposing the tar will help in re-fixing it by heating in case a layer is not pasted properly. Another imp thing in damping is to have a roller or a curved metal tool to press the material to cover all the nooks and corners of a metal part, i mean no air pockets should be there.

For the roof, better cover with Alum tar felts or use the same felt with alum foil pasted separately to reduce the heat.


Following is the material that I have used:

[DerAlte]

Originally Posted by ::CMS::

... Carpets wont prevent a surface from resonating unless its pasted. ...

Carpets, not pasted to floor, work for horizontal surfaces to suppress a large amount of reverberation. For decent NVH (not audiophile grade), car manufacturers apply tar-felt (yes, the cheap variety; before painting) to break up resonance in large surfaces without discontinuities (even Tata and Mahindra do it; one can spot it if looks into the door cavity / outer layer, as well as floor in some places). Discontinuities - bends, troughs, ribs - prevent the panel from reverberating / resonating. All car manufacturers use a layer of felt carpet just placed on the floor, held in place by door sill beading etc. And, they know a thing or two about NVH and panel reverberation.

Of course, if one is talking of audiophile grade damping, there is no end to damping one can do, limited by cost / benefit ratio inflection. Most other people actually look for just a decent improvement in NVH, as long as the cost is withing a couple of thousand bucks.

Originally Posted by ::CMS::

... have a roller or a curved metal tool to press the material to cover all the nooks and corners of a metal part ...

+100. Many installers just use balled-up cloth to press down. Others don't bother to do even that - just a perfunctory wiping by hand.

[::CMS::]

Originally Posted by DerAlte

Of course, if one is talking of audiophile grade damping, there is no end to damping one can do, limited by cost / benefit ratio inflection. Most other people actually look for just a decent improvement in NVH, as long as the cost is withing a couple of thousand bucks.

My total expenditure was 1200 or 1300/- for the felts + 150/- for 1kg tar + 400/- for Fevi SR + effort

[DerAlte]

Originally Posted by DerAlte

... Most other people actually look for just a decent improvement in NVH, as long as the cost is withing a couple of thousand bucks. ...

Originally Posted by ::CMS::

My total expenditure was 1200 or 1300/- for the felts + 150/- for 1kg tar + 400/- for Fevi SR + effort

I should have added "with no effort on their part" . That's where / why the cost goes up.

[condor]

Originally Posted by DerAlte

Most other people actually look for just a decent improvement in NVH, as long as the cost is withing a couple of thousand bucks.

Originally Posted by DerAlte

I should have added "with no effort on their part" . That's where / why the cost goes up.

.. missing the key part !

The effort to go and search for stuff + the effort to do it by oneself isnt always easy. I have pretty much given up on going to JC road & SP road due to the first part. It's exactly like searching for a needle in a haystack.

Originally Posted by DerAlte

+100. Many installers just use balled-up cloth to press down. Others don't bother to do even that - just a perfunctory wiping by hand.

I have used a small glass bottle, or the curve part of a wheel spanner ( the stock " L" type) with varying results. Have nicked my fingers too at times.

I am thinking of using one of those wheels that are used below furnitures.

[::CMS::]

Originally Posted by DerAlte

I should have added "with no effort on their part" . That's where / why the cost goes up.

Is the material cost same and more imp the quality of work, they are noway comparable. The felt was 20mtr, considering the thickness and wt, can consider 15mtrs compared to commercial ones. For a normal sized car, I would have to spend north of 25-30K just for the material for any vfm branded sheet, labor wont be so high 6-8K or 10K max

[DerAlte]

Originally Posted by condor

... I am thinking of using one of those wheels that are used below furnitures.

If you can, get a couple of used sponge rollers with a handle that house painters use. Discard the foam roll - the core can be used to press and roll on the damping sheet.

[vsathyap]

Is there anything in the market that we can use to dampen sounds from bare non-cladded wheel wells? I find the wheel and road noise quite loud in my Alto and would like to tackle this by adding some dampening material. Any suggestions?

[heydj]

In my Rapid for last few days I am hearing rattling noise coming from roof of the car upon hearing lot of bass music at loud volumes. When I lightly press the roof upwards near inside car light rattling goes away. I am talking about front inside light of the car where rear view mirror is also attached.

As per auto shop to dampen this place would mean ruining car roof as everything will have to be taken out. Any suggestions?