You can put all the plastic sheets on you want, but you still won't be
able to hermetically seal the sides of the van. Too much air flow from
elsewhere will still get in there.

And if you have a camper (or will be planning on sleeping inside your
van) the humidity you yourself exhale will still be able to get into
those areas. And then the temperature difference between inside and
outside, will cause it to condense. And once the cotton has absorbed
water, it won't give it up easily.

And yes, it is trapped moisture causing rust, which you are trying to
avoid.

On Apr 2, 2008, at 9:03 PM, Woody Halsey wrote:

> Dear All,
>
>
>
> Yesterday Ken Wilford recommended against using recycled cotton fiber
> home insulation bats to soundproof to my 83.5 V'gon. He warned that
> the
> insulation could absorb moisture that would be transferred to the
> fiberboard panels and lead to warping. That all makes sense (and I
> always values Ken's wise advice); but I would be curious to know if
> anyone has tried that solution and kept moisture from getting to the
> panels by renewing/replacing the plastic sheets that were
> (theoretically
> anyway - I don't think I ever saw them on mine) originally glued to
> the
> walls of the vehicle, behind the clip on panels. Is there also a
> risk of
> moisture getting trapped in the insulation that would then lead to
> rusting of the body itself, from the inside out?
>