[Bass&Trouble]

Originally Posted by ST7677

However I would wonder what would happen if the car meets with an accident and the panel needs to be dented and painted.

As Der Alte mentioned, the fiberglass has to be removed in order to perform denting. I dont see the point of painting the area under the fiberglass anyway. Right now my car's doors are getting ready for fiberglassing on the inner door skin.

[zerocritical]

Guys.. today i went hunting for some material that i can use for damping..
i found some, out of which i shortlisted two. Following are details:

First material:
4mm thick rubber sheet (dont know the exact material).
comes in 36X30 inches sheets.
Each sheet wieghs around 4kg.
This sheet had matt finish on both the sides. looked like the mat used by autowala's
for floor
Price : Rs.130/sheet

Second material:
2mm thick
comes in 24x18 inches sheets
each sheet weighs around 1kg.
This sheet has a bit glossy surface on one side and door mat type groovy finish on other side.
Particularly looked like a door mat.
Price: Rs.80/sheet

Both the materials were non adhesive and SR solution would be required to stick them on doors.

I personally think 1st material would be better for damping but only 4mm thickness is my worry. Can someone help me choose one of the above?

[swift8847]

I think the first material should be good because of its thickness.
Gagan, where was this store where you found these sheets.

And also I need to know if one of this sheet would be enough for the boot door(not sure as to what it is called).

[zerocritical]

found these at Shivaji nagar.. near charminar masjid.. many shops there stock these... I went asking for "RUBBER SHEETS for PACKING"

I think 4 sheets should be sufficient for front two doors and the boot hatch door.

[DerAlte]

Use whichever is stiffer when bent. If it is so stiff that it cracks up, it is no good. Good stiffness (not rigidity but enough resistance to bending) and high per-unit-area weight contribute to good damping.

Make sure you thoroughly clean the surface you want to stick it on with thinner or such solvent before applying the SR adhesive. Stick the sheet, pull it out, allow the SR to virtually dry before sticking the sheet back again by pressing with a roller.

[zerocritical]

Originally Posted by DerAlte

Use whichever is stiffer when bent. If it is so stiff that it cracks up, it is no good. Good stiffness (not rigidity but enough resistance to bending) and high per-unit-area weight contribute to good damping.

Make sure you thoroughly clean the surface you want to stick it on with thinner or such solvent before applying the SR adhesive. Stick the sheet, pull it out, allow the SR to virtually dry before sticking the sheet back again by pressing with a roller.

Thanks DA. I was advised to first rub the rubber surface with emery paper before applying the SR so that rough surface sticks better. Any comments on that?

[srishiva]

Isn't 4mm a little too thick ?

[zerocritical]

Tried 4mm sheet.. was not happy with this thing..

[zerocritical]

Called up Thouqeer from auto fusion. He was talking about some thermocol sheets with wooden covering for damping. would cost around 2500 for 2 doors + boot.

Else the cheapest damping would cost 4.5k for the same.

Any idea about this wooden and thermocol thing?

[DerAlte]

Originally Posted by zerocritical

... advised to first rub the rubber surface with emery paper before applying the SR so that rough surface sticks better. ...

Noooo! That is like the technique used for sticking stone tiles on vertical surfaces with cement. (One coats the mounting surface with araldite, sprinkles some sand - and you get the rough sand surface to bond with cement plaster). By making the surface rough, one increases the effective bonding area, reducing chances of bond failure.

Rubber-based adhesives work best with relatively smooth surfaces (not polished metal, of course). By cleaning I meant remove contaminants (oil, grease, moisture/water) and dust. Perhaps the emery treatment was suggested for removing rust and grime from the metal surface? Definitely not needed for the rubber surface (adhesive enters the small surface pores, which is enough surface area increase).

Originally Posted by srishiva

Isn't 4mm a little too thick ?

Not necessarily, depends on material. You must be thinking of ability to follow sharp contours - one has to press with a roller for better bonding.

Originally Posted by zerocritical

... thermocol sheets with wooden covering for damping. would cost around 2500 for 2 doors + boot. ...

Thermocol would be a decent damper only when compressed between two surfaces. Otherwise, with one side bonded on an open surface it's damping abilities are close to zero (very low density, very low weight). Thouqueer must be referring to (thin ply)wood as the other surface to get useful damping from the thermocol. Or creating wooden braces to put pressure on the thermocol. Can't visualize without seeing what he meant.

Nah, I'd rather use conventional damping materials for open surfaces, despite the cost.

[sonirohit]

Guys - Got myself some damping from LBM (Noisekill), LBM advised me to go for 40" stuff for the front doors + boot - however decided to go frugal with damping and asked LBM to send only 20" of noisekill - which was enough to cover the front door panels and the boot metal panels.

So decided to look for a jugaad for the plastic trims. So I headed out in look for something I could use... Went to a number of foam suppliers but they had nothing which would serve the purpose in the long run.

Then I came across a stuff used normally by cobblers (This is a sheet which was about 5 MM thick), has a matt surface on the both sides and was quite heavy, this cost me 150 for 4 Sq Ft and is quite heavy too compared to noisekill (4 ft of this sheet was weighing almost as much as 20 ft of noisekill). I asked the guy about the best adhesive to stick this to the plastic trims and he suggested Araldite. Went ahead & got a pack of araldite as well.

Here are the pics of the install.

1 - The sheet when viewed from top.


2 - This will give you an idea of the thickness of the sheet.


3 - Cut sections of this material and started placing them on the trim.




4 - This is how the final door trim looks like


5 - placed this in the sun for a couple of hours to let araldite do it's job.

The results - this sheet is approx 3 times thinker than the damping I've used (Noisekill) and atleast 4-5 times heavier than it's counterpart, and add the weight of araldite onto it. Performance wise It's added more mass to the trim than noisekill - however the process of cutting rubber into pieces and using araldite to fix it was a painful task. Price/Performance ratio of this is much lower than any other damping product and once it sets properly it does it's job quite well.....

This was done only on boot trim - and I'd have consumed abt 1.25" (60 Rs) of this stuff & 1 tube of araldite (65 Rs). so approx 125 Rs for 1.25 ft... not bad huh...

[Bass&Trouble]

Dont stick any of it with araldite on your door or any such metal part. In case you have to do any denting work, it''ll be tough to get it off.

[adityamunshi]

Synthetic rubber adhesive is the best for DIY damping work. It sticks quickly and comes off easily too.

[sonirohit]

Agreed B&T, I used it only on the plastic (or whatever) trims....for the metal parts Noisekill zindabad.....

btw - in case of a denting job won't noisekill or other damping also be a pain?

Originally Posted by Bass&Trouble

Dont stick any of it with araldite on your door or any such metal part. In case you have to do any denting work, it''ll be tough to get it off.

[Bass&Trouble]

Originally Posted by sonirohit

btw - in case of a denting job won't noisekill or other damping also be a pain?

Dont know about every other, but in Noise Kill and Dynamat, the material sticks to the Aluminium layer and comes off on pulling.