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#1062622 - 07/04/19 01:28 PM Foam Material Between Door Skins and Braces  
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cwest01 Offline
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My doors rattle when driving and when being closed. Upon close inspection, I can see that the foam material between the skins and braces (pink in color) has dried, cracked, and in many cases, fallen out. I would like to put something back in to reduce the harmonics. However, the 3M soft foam product requires a very large tool to apply. Our doors do not provide very much room for a tool like that. Can anyone share what they have used for this application that can be applied given our limited access?

#1062623 - 07/04/19 01:49 PM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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You could use sound proofing products like Dynamat. But that only puts a band aid on the real problem, the rattles. I would suggest repairing what is causing the noise, bad door weatherstrip, cracked window sweeps and loose window and door lock mechanisms. It's not the door, it's what is inside that is rattling. Reach up inside the door guts and shake the rods and levers to see what is loose and making the noise.
Do not use absorbent sound proofing products, they will absorb moisture and create a breeding area for rust.
I do not recall seeing a pink foam material between the braces and the door skins when I had my doors apart. That sounds like someone put that in sometime in the past.
Years of door slams makes the door rattle. Don't forget to check the door hinges for wear.
Some of the bracing could be cracked from all the abuse. That will require welding to fix.
The trouble is in the original door design. Long heavy doors with heavy door guts loosen up unfortunately.

Last edited by upflying; 07/04/19 02:54 PM.

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#1062627 - 07/04/19 04:44 PM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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Thanks for the feedback. I have all new OEM weatherstripping, glass guides, rollers, felts, etc. When I say foam, it isn't exactly foam, it is a caulk like material that the factory installed between the crash bar/ brace and door skins to prevent rattles. Over time, it hardens, cracks and ultimately falls out from the door being closed. The material is pink in color. 3M makes a two part epoxy that they call "soft foam" to replace the original when needed. I am sure it is the brace to door panel interference because I can eliminate the rattles by pushing the brace against the door skin. Problem is the two part epoxy has to mix when being squeezed out so it takes a large, specialty caulk gun to apply. I don't think I could get it inside the door enough to hit the target locations.

#1062641 - 07/06/19 05:35 AM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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mmc427ss Offline
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Here's a post about door seals. 2/3 of the way down the page 5 is how i tried to eliminate that rattle.
http://www.montecarloss.com/community/ubbthreads.php?ubb=showflat&Number=1061762&page=5


Here's that info:

"When previously having both door apart years ago to do beltline molding an attempt was made back then to fix the door skin to door guard beam urethane that dries out, falls into the bottom of the door, and causes that rattle when the doors are closed. The orange urethane was used to bond the door skin to the door guard at the factory. It's a very difficult area to access and re apply adhesive to stop that rattle. Tried to bridge the 3/8"-1/2" gap using RTV last time and was only slightly successful because that RTV will not bridge that gap and stay put. This time on the pass door made 9 short plastic bridges from the top edge of the beam to the door skin, affixed with RTV then once firmed up laid another coating of RTV down on the bridge to add more strength. I've seen spray foam used as the fix for this problem but thought that foam would retain moisture."

There may be a better product to use than black RTV but the above bridge and the RTV is flexible, waterproof and has quieted the rattle very well. If you still can see some orange urethane attached to either the skin or beam you can use the RTV to reconnect the orange stuff, Most of the time the urethane is laying in the bottom of the door. About 8 or 9 bridges were done on each door.
No more rattle when you close the door, and no rattle when you tap your knuckles on the outside of the door along the door guard beams glue points. RTV works pretty good.
Bob

#1062657 - 07/07/19 07:09 PM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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GregO Offline
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I too recall picking these loose pieces out from inside the doors going back 10+ years. Never did replace. We will see if more falls out later or any rattles get worse.

#1062659 - 07/07/19 08:57 PM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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Repacked with caulk when we rebuilt car about 8 years ago. Need a soft material to dampen and to provide some flex lest it form a hard ridge across the door. Also, no water retention. Back to you on this later when I dig into it again....
Gordon

#1062681 - 07/09/19 02:21 PM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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Chris - I talked to my body shop. They used a two part urethane closed cell foam product. 3M and others make these for reduced NVH (noise, vibration, and harshness). Will not absorb water, and will not create a hard ridge against which the door panel might crease. The 3M Flexible Foam 08463 is carried by Zoro, Grainger and others. About $40 with, I think, two static mixing tubes (use one time each?) which should get you into the space. Or find a tool to push it down and in at the ends?. Here's a quick look:
https://www.zoro.com/3m-flexible-foam-nvh-08463/i/G0406463/
Keep us informed please on what you learn and how it works out for you.
Gordon

PS - you could also buy from a friendly body shop? I'd get you ond from mine if you were closer.

#1063255 - 08/21/19 06:49 AM Re: Foam Material Between Door Skins and Braces [Re: AkronAero]  
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Headstrong Offline
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Originally Posted by AkronAero
Chris - I talked to my body shop. They used a two part urethane closed cell foam product. 3M and others make these for reduced NVH (noise, vibration, and harshness). Will not absorb water, and will not create a hard ridge against which the door panel might crease. The 3M Flexible Foam 08463 is carried by Zoro, Grainger and others. About $40 with, I think, two static mixing tubes (use one time each?) which should get you into the space. Or find a tool to push it down and in at the ends?. Here's a quick look:
https://www.zoro.com/3m-flexible-foam-nvh-08463/i/G0406463/
Keep us informed please on what you learn and how it works out for you.
Gordon

PS - you could also buy from a friendly body shop? I'd get you ond from mine if you were closer.



I don't know, but most foam retain moisture . and why most vehicles from the late 90- and 2000's up the rockers rot from the inside out.
I know there are many types of foam. but the stuff in between the framework and skins (door/trunk/hood) don't feel like foam.
Feels more like calking that was aerated when applied.

But what I'm feeling is 30+ years old so , take that for what it ia worth.
The stuff in my older car feels like a cross of dumdum and chalk.
or an expanding glue.

#1063304 - 08/24/19 09:24 PM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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MAP Online content
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Hi Folks,

I'm sure AkronAero can shed more light here, but there's no such thing as a foam that doesn't have at least a little porosity and permeability, even if it's alleged to be closed-cell foam. So, a problem with rust is always a possibility with any foamed material. And that's still true even if GM used a foam - remember that they built cars back then to be driven on average maybe 75k or 100k miles before retirement, so infinite life - which is how we think of our cars - wasn't exactly their intention. After all, they wanted you to be repeat car buyers => $$.

I'd use an un-foamed, soft visco-elastomer with a very generous gap-filling ability. Also, make 1,000% sure the surfaces you're bonding to are surgically clean and free of any foreign materials like greases, waxes, dust, etc. Hitting the surfaces with a fine Scotch-Brite, or about #320 grit sandpaper is good too, provided you don't break through the factory surface treatment, which is probably some sort of zinc-based primer.

Here's another approach that might work better: do all of the above, of course, then tightly apply a patch of thin Dynamat (or the like) to the area of the doorskin you want to dampen, and the area opposite this on the impact beam. Then, get some kind of heavy, dense, closed-cell foam, and use this to bridge the gap in-between the two Dynamat patches - that is, force it into this gap with mild compression: enough that it stays put with only the compression, but not so much that you deform the doorskin. Once this foam pad is in place, hit its perimeter with an Si-based elastomer caulking to ensure the pad stays put forever. You probably only need about a dozen square inches or so for the two Dynamat patches, and the inserted foam pad. Give yourself some safety margin by having the Dynamat patches to be larger than the foam pad, however, so we don't have any foam in direct contact with any metal.

One thing about applying Dynamat in any area that can get wet, which is 100% guaranteed with a car door: it's CRITICAL to make sure the patch gets tightly bonded EVERYWWHERE to the metal surface you want to treat. You don't want to leave any tiny gaps where water can enter. If you can't ensure this, then run a continuous bead of caulking around the entire perimeter of the patch after bonding, to ensure no water entry. If you imagine you're applying a patch to a leaking aquarium, you'll be thinking correctly smile

One more thing: try to do this project on a very dry day.

Akron, back to you on this one!

HTH,
MAP


Last edited by MAP; 08/24/19 09:42 PM.
#1063305 - 08/25/19 12:43 AM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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AkronAero Offline
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MAP
... and do this in MAP's garage in Yuma AZ.
Question, is there enough moisture in the air there to condense on a cold beer? I am hoping to find out this fall!

Darn, I was in the shop today Chris on another project and I forgot to follow up with my guys on the foam. They may have easier options for the DIY guy. Or I could borrow their gun and drop it off for a weeknd on my way west this fall?
Did get to play a bit with a 1986 Grand Prix 2+2 that is in for repainting (etc).
I recall my Aero has a 14" opening in the trunk. The GP is down to 11". Wish the back windows were hinged.

Back to the subject: I am hoping to find a simple hand dispensing material that doesn't require the $70+ dollar gun for the two part system. Again, a good body shop would have all this and could do it...
The reason for the closed cell urethane foam is to get a runny fluid into the small joints/crevices, and have it expand rapidly to fill the voids (Urethane does this as the two part curing reaction releases CO2, just like soda) land get thick (stop running), leaving behind sealed voids (vs open cell foam which absorbs and holds water) and is in the rubbery range to take up movement and reduce noise transmission. The 3M product is widely used for that; probably a variation is used in the manufacturing plants???

Yes, the issue may not be this foam but what is trapped underneath. I wanted to put the fatmat rattletrap on the door skin to cut down on noise but the shop was really VERY negative about this as it might also trap junk underneath.
If you did caulk it, MAP, I would not caulk the bottom but leave that open to drain and air out.
Having said all this, when I look inside our doors its not like a fender... there just ain't much room to play.
So I'll stick with a light application of the the two part foam as described. Mine has been in about 10 years with no sign of rust at the reinforcement brace . Garaged yes, but been dumped on more than a few times.

Chris I still owe you a response.
Gordon

#1063343 - 08/27/19 04:36 PM Re: Foam Material Between Door Skins and Braces [Re: cwest01]  
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AkronAero Offline
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Chris - Here's my summary:
The only cleaning you need to do is maybe knock out some of the old stuff if its hanging in there, but it is not at all necessary.
You should use an expanding two part closed cell flexible foam designed for this application. Did I say flexible?
The 3M product I referenced before works well and is a standard.
My shop prefers to use Lord Corp's Fusor line, equally reputable. Both may claim some anti-corrosion capabilities.
For each door you would want to have one 50ml cartridge of the flexible two-part foam (Fusor #124) for under $20 each.
You get two mixing/application tubes with each cartridge. I could send you some extras but four should be more than enough.
You would need an application gun (Fusor #300) for the 50ml cartridge at a cost of about $50.
Alternatively you can get a generic 50ml applicator from US Plastics Co (Manual Adhesive Dispersion Gun) for about $35 on the internet
There are also no-name brand guns at Amazon for under $20.
Have everything open and ready. Do a dry run to get your sweep and speed/timing down and identify problem/restricted areas.
Make one steady pass running a small bead on top of, and behind, the rail.
It starts reacting immediately and is fully set in a few minutes.
It will run down behind as it expands. Cap the applicator if any left.
Flexible aspect important so as not to distort or create hard break line at door.
(this is why Great Stuff has the soft flexible foams for around doors and windows so it doesn't distort).
So you can do all this for under $100, perhaps as low as $60 + shipping.
That's as good as it gets.
Feel free to contact me anytime.
Hope to see you soon.
Gordon


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