Felt / Sound deadening

[mini_surfari]

Afternoon!

Want to get the noise down and eliminate a few rattles in the van.

Looking at woolies trim amongst others, any ideas what thickness is used for the roof lining? Think I'll do behind the door cars after as well!

Cheers!

[mk1]

The original stuff was about 1/4" thick. Probably better to use some bitumen pads nowadays, I have read a lot of good about them on here. I'll leave it for someone who knows more than I to comment.

[Peter Laidler]

I know about as much as Mark (above) does but I'd say avoid any form of matting or sponge like the plague. Don't believe them when they say that it is moisture retardent/resistant. It sops up water and moisture like a sweating camel riders jock-strap. Stick with that specially made bitumen pad stuff.
(PS..... if the pads have squared-off corners, the corners peel away. To prevent this, cut a 1" around the corner bits)

Just my experience

[mini_surfari]

Thanks guys,

It's got bitumen pads on all surfaces that cant be seen, was hoping a little more could be done.

I know a van will never be a Rolls but at some revs the vibrations are truly awful

[swifty]

I use the latest imitation lead flashing from wickes . It’s ultra sticky but easy to cut and smooth out …. Shirley

[Peter Laidler]

That's a good idea..........

[Midnight Blue]

As Mark suggest, the butyl damping pads are excellent for attaching on panels, much better than felt. They will help attenuate the noise and reduce the frequencies. Felt is remarkably poor as a sound reduction material.

From experience working with noise, vibration and harshness (NVH) engineers on various vehicles, I would suggest using butyl pads to reduce noise from panels and structure borne noise, basically the road noise and vibrations transferred around the body panels and structure.
The are many products available. Dynamat is one of the better known brand names. Henkel sound deadening products are widely used by the vehcle manufacturers.
Search the web for Dynamat. The specs are available from this link.
https://www.dynamat.com/wp-content/uplo ... et_Web.pdf

I like the ingenuity with thinking about using imitation lead flashing. It could be ok, and it's cheap and readily available so worth experimenting with. It's likely to be quite a bit less absorbent than the purpose designed sounds dampening pads and you would need more of it to get the same performance.

It's also worth considering a sound absorber material - typically this would something like a open cell foam such as Armacell RD240 (the Rolls Royce of sound absorption foams) with a heavy barrier material such as a 2mm rubber sheet attached to the outer surface. This is a great combination to reduce airborne noise levels from the exhaust, transmission, tyres and more. Every open hole on a car allows airborne noise in. The noise finds it's way past all the grommets etc and the sound absorber material can significantly reduce it.
As Peter mentions, foams can by absorbent, some such as the Armacell are good at resisting water ingress, whereas others can be way too absorbent to consider. Info on Armacell RD240 is available here:
https://local.armacell.com/fileadmin/cm ... KROI-1.pdf

I did a quick search on the interweb but didn't find any particular guides that could be helpful.
What I did find was this article in Miniworld that seems useful to show where to put some of the material.
https://www.nkgroup.co.uk/wp-content/up ... rticle.pdf

I have no afiliation with these guys and they seem to have a good product range, and possibly have a good understanding of the subject:
https://www.carinsulation.co.uk/

Rattles tend to be more related to specific parts vibrating due to the engine vibration, road inputs or other sources. For example, as the vehicle travels down a road, the vehicle movement may trigger engine movement that feels like a vibration, or it can trigger vibration in the doors, seats, other interior parts and much more. This vibration relates to the mass, (installed) stiffness, damping and location of the parts. To eliminate the rattle change one or more of those factors...

Hope this helps.

By the way I have no links with any of the products mentioned above!

Mark

[mk1]

WOW!

That is what you call a comprehensive answer!

Thanks Mark

[mini_surfari]

Thanks very much!!

In that case, looks like an acoustic foam would be the way to go, and over lay the bitumen.

Really need to get the rear door seals sorted as well as they rattle like nothing on earth!