Author Topic: What paint to use over sound deadener.  (Read 2826 times)

Offline mungus

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What paint to use over sound deadener.
« on: March 21, 2021, 03:15:47 AM »
My 68' Fastback has quite a bit of that black, wavy, spray on bituminous sound deadener in places like the rear quarters & trunk seams, in the wheel houses, and in the passenger cabin around seams etc. Its very sound (no pun intended) and I don't think it needs replacing.

So my questions is what primer and paint can be used over this stuff? There were remnants of factory colour over it...

I've read some sad stories from folks saying you can't really paint over such stuff. Along the lines of thinners / reducers dissolve the sound deadener or the black colour bleeds through etc. Any ideas? Its easier to ask then buy and apply the under sealant on a test panel, wait for it to harden up and try various primers / paints over it, etc.

It would be a big & messy job to remove all that sound deadener / sealer and use a newer (more paint friendly?) product. Or is that the only good option?
« Last Edit: March 21, 2021, 03:20:24 AM by mungus »
March 14th 1968 - Metuchen S code Fastback
C6 auto, LS 3.25 diff, Gulfstream Aqua, Black Vinyl, Headrests, Console, GT group, PS, PB, AM/FM stereo, F70 tires, tinted glass, louvered hood.

Offline J_Speegle

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Re: What paint to use over sound deadener.
« Reply #1 on: March 21, 2021, 03:24:51 PM »
As long as its clean, well attached (not flaking) and so on I've always treated it just as the factory apply primer or depending on location paint over the product. Often it needs a little touch up here or there for contact so the painting follows after addressing those issues. On lighter colors the changing of tint is something that just took place originally and may or may not take place with the newer paints and few if any of the current sound deadener products will produce the same effect today - at least for me.

In other areas where the sound deadener is not painted over the challenge is often how to make the original stuff look fresh and new
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline mungus

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Re: What paint to use over sound deadener.
« Reply #2 on: March 21, 2021, 07:03:48 PM »
Thanks Jeff,

I was planning on using my usual high build grey primer over it inside the car and a 2K red oxide in the well houses.
Its a good match for the factory primer and a far better product. (Marine 2K by Intergard)
I guess all I can do is give it a try somewhere unobtrusive and pray to the big man it sticks and hardens with no bleed through!  :)

The sound deadener itself is in good condition and scrubbed up nicely with warm water and sugar soap.
Down here in OZ we use a bituminous deadner that is sold with a large bore sprayer attachment, that replicates the wavy black OEM stuff very nicely indeed. Smells and looks the same as OEM. If I do have to patch some bits, that's what I'll use. Its the go to for 1960's / 1970's Ford restorations down here.

https://www.rustoleum.com.au/product-catalog/consumer-brands/motospray/under-body-and-bumper/sound-deadener-spray-on

https://www.4x4andoutdoor.com.au/raptor-coatings-application-gun


March 14th 1968 - Metuchen S code Fastback
C6 auto, LS 3.25 diff, Gulfstream Aqua, Black Vinyl, Headrests, Console, GT group, PS, PB, AM/FM stereo, F70 tires, tinted glass, louvered hood.

Offline J_Speegle

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Re: What paint to use over sound deadener.
« Reply #3 on: March 21, 2021, 10:27:28 PM »
Not sure why a high build up primer would be the choice for areas like the trunk and interior unless your looking to hide or cover rust pitting or other ills. More likely it will blur the details, make edges appear thicker and so on.  Just making the overall look less factory like.  We see the same thing on the exterior of the car on some examples to the point where they often get described as "dipped in paint or plastic" look. Get for those custom shows and modified cars. Not what many restorers are looking for

If you the gray primer in the trunk area or any travels from the interior or can be seen you need to make sure its later covered with body color unless if it's in an area that didn't receive much or any body color.

As always - your car your choice  :)
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline mungus

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Re: What paint to use over sound deadener.
« Reply #4 on: March 22, 2021, 08:04:27 PM »
Thanks Jeff, sound advice.
I'll just use my usual 2K red oxide primer then. It matches the factory stuff left behind upon disassembly.
I will ensure no primer is visible there once done.
March 14th 1968 - Metuchen S code Fastback
C6 auto, LS 3.25 diff, Gulfstream Aqua, Black Vinyl, Headrests, Console, GT group, PS, PB, AM/FM stereo, F70 tires, tinted glass, louvered hood.