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Re: [T3] Insulation in the doors.....

Bill Niles asked about insulation in doors.....

Bill was right, there really is not insulation in the doors as
built.  The question you have to ask is why do you want to
insulate the doors in the first place. Do you want a quieter
ride? Do you want less heat loss?  What are you after????  

Heat loss is not usually a big problem....the large dead air
space inside the door is a very effective thermal insulator.

Most of the time insultion that is added to cars is for noise and
vibration control.....dead air space is not much of a help here. 
Adding fiberglass batting would not be very effective at
attenuating noise, although it will help some.  What you really
want to do is eliminate the source of the noise.  Usual culprit
is the vibration of the large unsupported sheet meCLnzls
(door skins, floorpans, roof panel)  VW recognized and tried to
help on the biggest culprit, the floorboards.  They have ribs
stamped into them to make them stiffer and they have the tar mats
on them to increase the mass of the panel (mass damping).

Ribbing the door skins is generally frowned upon by automotive
stylist (one noted exception is our cousin the VW Thing).  So the
most common solution is to use mass damping.  The Dyna-Mat and
Road-kill and some others.....(I think JCWhitney has some that is
cheaper) use this principal for noise control.  Make the panel
more massive (i.e. add weight) and it will not be excited at
lower frequencies and thus won't make noise.

As others have said this stuff is on the expensive side and it
does add quite a bit of weight.  It also very effective at
reducing noise.  I am planning to use it on my project Fasty. 
They also sell aluminum faced materials that are very good at
reducing heat as well.....I will use it around the engine

I don't think the spray-in foam will be very effective for
noise.  It is lightweight and probably won't attach itself to the
steel panel very well.  This attachment is critical if you want
to reduce noise.  It will also be difficult to make sure the
windows and door latch mechanisms still work.  It could also fill
in the drain holes and promote rust as someone else already

Another option that will help some would be to spray a heavy
layer of undercoating inside the door.  (be still your healing
heart Keith, if you are out there) If you do this PLEASE make
sure the door drain holes are left unclogged.  You do not want
the door to fill up with water and promote rusting.

Enough for now....I will let the list know how the insulating
goes on the Fasty when I finally get around to it.

John Jaranson
"71 FI Auto Fasty

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