The condensation issue is what makes the foil/bubble/bubble/foil material so
attractive; It has no absorptive capacity, and the R value is very high for
its thickness.  It has my vote.

On 1/23/06, Max Wellhouse <maxjoyce@ipa.net> wrote:
>
> Only closed-cell foams are water-tight/proof and even condensation
> will form on them which could create a rusting
> scenario.  Polyurethane and styrofoam are open cell foams and will
> absorb water.  In your example of using them for dock floatation,
> yes, they don't sink but if you weighed the float before it was
> installed and weighed it a year later, you'd be able to calculate how
> much water it soaked up.  Did the dock sink due to the water
> absorption?  No, because the water won't get very far into the core
> of the foam.   In your Westy's case, the water doesn't need to get
> very far before it stays put and begins the rusting/mildew/mold process.
>
> I thought I was smart by using yellow fiberglass insulation to
> insulate my 71 Bus years ago.  a year later, I had a reason to pull
> the panels(speaker wiring I  think) and was horrified as to the rust
> forming in there and how wet the fiberglass was.  That van lived it's
> whole life in Arkansas so salt/rust wasn't an issue, but humidity was
> definitely in play.
>
> Bad news is that I don't have an answer for you.
>
> DM&FS
>
> At 01:24 PM 1/22/2006, Jake de Villiers wrote:
> >We4ll, they use polyurethane spray foam as fltation for docks and piers,
> so
> >it must be a closed-cell foam. Make sure you use the "Minimal expansion"
> >type Malcolm! The regular gets VERY big.
> >
> >On 1/22/06, David Marshall <mailinglist@fastforward.ca> wrote:
> > >
> > > I would be concerned about the ability of the product to absorb
> water...
> > >
> > > David Marshall
> > >
> > > Fast Forward Automotive Inc.
> > > 4356 Quesnel-Hixon Road
> > > Quesnel BC Canada V2J 6Z3
> > >
> > > Internet          http://www.fastforward.ca
> > > Email     sales@fastforward.ca
> > >
> > > - Engine Conversions and Accessories for classic water-cooled
> Volkswagens
> > > - Electrical harness fabrication and customization
> > >
> > > Due to the large quantity of email we receive, please include previous
> > > email
> > > correspondence when replying.  This will allow us to read the full
> > > dialogue
> > > in one message so that we may provide you a quicker and more accurate
> > > response.
> > >
> > >
> > > -----Original Message-----
> > > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> Behalf Of
> > > Malcolm Stebbins
> > > Sent: January 22, 2006 9:39
> > > To: vanagon@GERRY.VANAGON.COM
> > > Subject: Spay expandable foam insulation in Westy?
> > >
> > > In removing the interior from my "new to me" van, I notice that in
> some
> > > places (in behind pillars
> > > and panels), there is NO insulation, and NO way to get bubble or
> > > fiberglass
> > > insulation in behind
> > > the panels.  There are two major areas, each 1 foot by 2 feet.
> > >
> > > I know that there are spray expandable foam insulation products on the
> > > market.  Is there any
> > > reason that I should/could NOT use a product like this in a camper?
> > >
> > > Is there a human lung-friendly product that will not out-gas forever
> and
> > > kill me slowly while I
> > > sleep???
> > >
> > > Thanks.  Malcolm
> > >
> > > __________________________________________________
> > > Do You Yahoo!?
> > > Tired of spam?  Yahoo! Mail has the best spam protection around
> > > http://mail.yahoo.com
> > >
> >
> >
> >
> >--
> >Jake
> >1984 Vanagon GL
> >1986 Westy Weekender "Dixie"
> >www.crescentbeachguitar.com
>
>
>

--
Jake
1984 Vanagon GL
1986 Westy Weekender "Dixie"
www.crescentbeachguitar.com