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Bonnet Insulating Mat

2taol

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Location
Ireland
Car
'11 Accord 2.2 ES GT
Hi all, i bought a new to me tourer at the weekend and noticed that the bonnet surface gives way when i put my hand on it and closing it results on an empty resonating sound, it has its insulating mat attached but is a bit loose. I still have my 7th gen tourer and its bonnet is solid.

Before i investigate is there supposed to be another form of padding, soundproofing or other stuck to the under side of the bonnet?

Thanks in advance
 
Mine has a contoured panel held with clover leaf shaped fir tree clips. Underneath there appears to be a layer of fibre / foam.

I've tried to add a couple of pictures, but my picture host has recently moved to a new site and it's mostly in German (which I don't speak) :unsure:





I had a 7th Gen previously, but can't remember the bonnet note particularly. Back when I swapped from 7th to 8th, I did think the 7th felt more solid in many respects. Had a nicer door close thud etc. I've not let it spoil my 8th Gen experience though :D
 
Thanks Matt, Yes at least the heat shield is present although it wuld be hard to miss.
I removed this today and noticed the bonnet outer skin has come away from the
subframe. the images show the glue spots have ripped away leaving about an inch
seperating the two . . . strange because the bonnet looks to be aligned properly :wacko:

IMG_20190429_200514.jpg


IMG_20190429_200530.jpg
 
Maybe the support was pulled upwards onto the bonnet skin rather than the skin being pulled down to the frame?
 
If the skin isn't out of shape, I would fill the spaces between the sub and the skin with expanding foam and then cut and glue in pieces of fiber matting in the hollows. Reinstall the black underbonnet mat, and it should be both stronger as well as quieter than before.

Oh yeah, and you can spray the underbonnet mat with black spray paint to make it look like new again.
 
Thanks for the replies, yes the outer skin is sitting perfectly. Would any expanding foam work or would it need to be heat sensitive?

Sounds like a plan!
 
I think any expanding PU foam / adhesive should work. But read the specs on the can for temperature details rather than take my word on it. But if it can stand metal roof and hot water pipe temperatures, car skin temperatures should be OK. Do clean the surfaces with carb cleaner so it will stick. if the surface is oily it won't adhere.

Spray foam can be messy to work with, especially when you are getting a feel for how much to spray into a particular cavity. Let the stuff bulge out a bit and then use a sharp knife to cut off the excess once it has cured. There are pages online that explain how to work with the spray foam.
 
So I have heat resistant expanding foam and heat resistant spray paint for the mat got
and just waiting for some self-adhesive closed cell foam for the gaps between the sub frame of the bonnet
before I attack this little project.

Images to follow

Thanks for the help!
 
Finally got around to repairing the underside of the bonnet.


Fire resistant expanding foam sprayed intermittently to allow for proper expansion
Heat and water resistant self adhesive closed cell foam for between the webs
Heat resistant paint to rejuvenate the mat
And some new plastic fasteners to fix the mat to the under side of the bonnet


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Actually there isnt any difference that im aware of. The mat was there to begin with so the task was to stop the bonnet from flexing while washing and polishing and risk denting
 
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