Author Topic: plastic sheet behind the panel  (Read 1017 times)

raueda1

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plastic sheet behind the panel
« on: 19 April 2021, 09:59 AM »
All cars seem to have it but it's purpose has never been very clear to me.  Naturally it's missing on my drivers door. Probably others too.  I'm gong to craft a new one but I'd like to know why I'm bothering. Maybe slight reduction in draftyness or wind noise, among other things?  Thanks and cheers,
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Alec300SD

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Re: plastic sheet behind the panel
« Reply #1 on: 19 April 2021, 11:07 AM »
The vapor barrier keeps the fiberboard of the door card dry when it is raining outside.
The fiberboard will get moldy and disintegrate if it gets wet too often.
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raueda1

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Re: plastic sheet behind the panel
« Reply #2 on: 19 April 2021, 04:37 PM »
Great, thanks.  I'll replace it.  Somebody just had a small barrier over the window regulator spring hole.  Happily the door panel shows no signs of moisture whatsoever.  Nor does the rest of the door - dirty and greasy but no rust at all.  It's nice to occasionally get good news on this stuff!  ;D  Cheers,
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

raueda1

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Re: plastic sheet behind the panel
« Reply #3 on: 24 April 2021, 09:39 AM »
Follow-up topic:

It's obvious the plastic door liners were originally glued in place.  It looks like some kind of solvent-based adhesive was used, probably similar to contact cement.  These days solvent-based adhesive are generally frowned on and lots of cars use a putty-like sort of caulk stuff similar to this: 
https://www.amazon.com/gp/product/B000LNODSQ?pf_rd_r=H2M34246KBJNK85R38EM&pf_rd_p=5ae2c7f8-e0c6-4f35-9071-dc3240e894a8&pd_rd_r=f75f3eef-68ce-4427-af2b-bc9e10029ff8&pd_rd_w=FT9Ud&pd_rd_wg=4U9Mj&ref_=pd_gw_unk 

It's too thick to be used as-is.  However, a single strand can be easily rolled out into a thin tape and applied to the door.  I've done it on other cars with good results.  It does a better job of sealing without gaps than glue with the further advantage that the sheet can be peeled off and then reattached.  But even if it's rolled out, it's a lot thicker than the adhesive originally used, say ~1mm vs <0.1mm.

So here's the question:  Does anybody know how tight the clearance is between the door panel and the door itself?  We all know how easy it is to break off the panel clips.  I'd hate to do that by adding to much thickness to the door.  Thanks as always and cheers,
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

daantjie

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Re: plastic sheet behind the panel
« Reply #4 on: 24 April 2021, 01:41 PM »
Another one of my go - to 3M products is 3M Strip Calk.  Great stuff, you can use it for so many applications, this being one.  It comes in thin strips which you can roll out or bunch up as needed.  The stuff is nice and easy to work with as it does not stick to your hands and you can mold it to shape as well.  Another great use for it is to cover the AC expansion valve once you get all that factory crap off there to replace the old valve :o
Daniel
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UTn_boy

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Re: plastic sheet behind the panel
« Reply #5 on: 25 April 2021, 03:53 AM »
Another one of my go - to 3M products is 3M Strip Calk.  Great stuff, you can use it for so many applications, this being one.  It comes in thin strips which you can roll out or bunch up as needed.  The stuff is nice and easy to work with as it does not stick to your hands and you can mold it to shape as well.  Another great use for it is to cover the AC expansion valve once you get all that factory crap off there to replace the old valve :o

The original cork tape is still readily available, and very inexpensive. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1971 280sel Black/black leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex

raueda1

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Re: plastic sheet behind the panel
« Reply #6 on: 25 April 2021, 09:37 AM »
Another one of my go - to 3M products is 3M Strip Calk.  Great stuff, you can use it for so many applications, this being one.  It comes in thin strips which you can roll out or bunch up as needed.  The stuff is nice and easy to work with as it does not stick to your hands and you can mold it to shape as well.  Another great use for it is to cover the AC expansion valve once you get all that factory crap off there to replace the old valve :o

The original cork tape is still readily available, and very inexpensive.
From this I infer that the cork tape is indeed OK for the doors?  If so, that's great!  I already have tons of it from another project. I was afraid it might be too thick.  My car has no trace of it and the use of glue is very obvious.
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

rumb

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Re: plastic sheet behind the panel
« Reply #7 on: 25 April 2021, 04:56 PM »
I think the cork tape is for the expansion valve mentioned.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

UTn_boy

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Re: plastic sheet behind the panel
« Reply #8 on: 25 April 2021, 07:05 PM »
Sorry for the confusion.  Yes, I was replying to the post about the a/c.  For the vapor barriers a simple aerosol glue on a can is all that is needed. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1971 280sel Black/black leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex