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Is sound deadening on floor pans a good thing?

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MTribe

MTribe

Jedi Hopeful
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I'm repairing some light floor pan rust and having them repainted. The painter asked if I wanted to put down a coat of paintable (non-rubberized) sound deadening under the paint.

At first I was excited, thinking Triumph would have done this if they wanted to spend the dough, and I bet it's pretty effective compared to other sound deadening techniques.

But now I'm having second thoughts.. the visceral feel of the car and all the noises it makes are why I like it!

Anyone have experience with spray-on, paintable sound deadener on floor pans, and have any advice for me?

Thanks!
 
No experience...but, I say why not? Engine sound
is what I like; the road noise I could do without.
Long as it's not overly pricey.
 
I say no. Floorpans are moisture magnets and as such need to breath. I would not trust anything that wasn't inherently part of the floor, such as high quality paint or coating (POR15, etc.). Just wouldn't feel right not being able to see if any kind of moisture was creeping between the sound-deadening coating and the floor.
 
Why so skeptical you ask? Having recently replace my floorboards makes me so.
 
Interesting--the reason the painter originally suggested it was to encapsulate the floors to keep moisture out. He said it was a tough coating and would be better than paint to keep moisture out. Hmm... anyone have moisture get through this stuff?
 
I would think a coating similar to Rhino Lining used on truck beds would both deaden the sound and provide a rust barrier. Goes on with a paint roller.

I cut out some heavy asphalt sound sheets (like Dynamat) for car stereos to match the floor carpets but I wimped out on installing it because I was afraid water could creep under it and start rust.
 
Interestingly, the rubber/tar-looking sound deadening material that comes original on all the TR6s never let moisture underneath it. I have removed this material from several cars and the primed sheet metal underneath was always factory fresh. Seems that this stuff was available from TRF some time back. Might still be; if it is as good as the original, don't know.
 
I concur with Bill, two other TR6's and the original stuff behind the seats when taken up had pristine primer under it.
The idea of this stuff is to dampen the vibration of the metal which amplifies the noise from whatever source.
Today, I would not use an asphalt based sound deadener. The better new products are a butyl based product. It sticks better, holds up in higher heat, and seals better.
I am using RAAMat product. I still have not decided on if I will put it to the floor pans. I am leaning that way, but haven't committed. I am thinking that the way this stuff sticks, that applied to a sound surface it will seal water out.
I think the sticking nature of the product will alleviate air pockets which could have condensation form and then cause pockets of moisture which would lead to rust. It doesn't have to cover the whole pan to help reduce the vibrations. So I may start with a single square area.
This product is here https://www.raamaudio.com/cgi-bin/index.cgi?p=hm&cert=7981da351255ab38bc280d3e907cd77d
There is a link to a good article on the different products here. https://www.sounddeadenershowdown.com/
Remember this is being driven by audio types, which may not be what a LBC owner is after, but noise reduction principles are the same.
FWIW.
 
PeterK said:
Here's the stuff I have. https://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-020

I'm thinking about adding a double layer piece to the timing cover to replicate the original dampening. What do you think?
Click to expand...

I used that stuff in a pair of floor-standing loudspeakers ... worked great: reduced the cabinet resonances significantly.

Does there exist a product that seals and deadens sound which can be painted on with a brush or roller?
 
OK--I decided to have the painter spray on the sound deadener.

So far so good! It's amazing--when you tap on the floor pan it makes a thud sound, and the coating is not very thick, probably about 1/32". It was developed for rocker panels, so it's tough and should protect the floor well. It just looks like paint, so it should keep moisture out.

Been trying to upload pics since last night, but it's not letting me and I give up. Would be nice to share the results.

Also, the painter highly advised against adhesive-based sound deadening panels (like dynamat). He said even with a heat gun during application, there will always be air pockets which will eventually cause rust. And furthermore, with the channels in the floor pan, it'd be impossible to totally seal it from moisture, and you'd never know if moisture got in there anyway.

Good to hear about the factory sound deadening panels being moisture-free. I decided to leave those undisturbed (on rear shelf and just behind seats), and just paint forward of those since there was no rust there.

I also found a great seam sealer product I'll also upload pics of if the server ever lets me!

More results to follow...
 
I used some stuff from Aircraft Spruce; it's made to line light aircraft firewalls. It is meant to reduce heat/noise/vibration. It's foilfaced and self adhesive. Works great; not cheap though.
 
MTribe
What is the name of the sprayable product your painter used?
As I noted in my earlier post. I was wondering about voids and causing condensation and rust. So another input against it and I am don't think I will put it on the floor pans.
Also the name of the seam sealer product?
Thanks
Mark
 
I'm very happy with the spray-on sound deadener on the floor pans. The painter said it was 3M "rockershultz" (or at least that's what I heard), but I couldn't find that for the life of me online. So maybe I'm off on the name. It's very thin--just sort of like thick paint, versus the spray-on rubber stuff. It makes a noticeable difference when you tap the floors with your finger. Makes dull thud instead of a metal sound.

Dynatron #550 Seam Sealer Gray was the seam sealer. Got it from Napa and it worked great.
 
Here's a real Q/A page about insulating auto cockpils:

https://www.quietride.com/faq/default.htm

I used a foil faced, 1/2 thick auto heat/noise product
and my car here in the tropics is at least 20 degrees cooler
inside and much quieter as well.

As an architect, we give paint a zero insulation value.
Some really funky $$$$$$ paints might deaden sound a bit.

Did your mom put mittens on your hands in winter or paint them?

d
 
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