[Rhodes22-list] ...on spray foam and other musings....

Tue Feb 14 14:05:21 EST 2012

The key to decreasing condensation on a R22 is air movement. I doubt that  
insulation would hold up very well in our small craft. Years ago I mounted a 
 small 12v computer fan behind a stainless steel cowling on the  hatch. 
Plugged into 12 volt and eliminated all the mold and mildew I had  experienced 
previously. Much easier than insulation. There isn't enough exposed  hull to 
make it practical in my opinion.

Rummy

In a message dated 2/14/2012 11:50:02 A.M. Eastern Standard Time,  
spreadgoodnews at gmail.com writes:

To  decrease interior condensation.  Now that i think more about it 
tek-foil  might be a better option.

On Feb 14, 2012, at 9:29 AM,  R22RumRunner at aol.com wrote:

> Bob,
> I'm just curious, why  would you want to insulate the interior hull of a  
> R22?
>  
> Rummy
> 
> 
> In a message dated 2/14/2012 8:32:59  A.M. Eastern Standard Time,  
> spreadgoodnews at gmail.com  writes:
> 
> Thanks  Rob.  I am building out a 43' steel  sailboat hull.  I am 
finishing  
> the final interior epoxy  coats now then i will spray closed cell 
> polyurethane  foam all  over the interior hull over the stringers and 
ribs.  Then i 
>  have  read i should spray a fire retardant elastomeric paint over the  
foam to 
> resist  ignition in case of an interior fire. This foam  will insulate as 
well 
> as  contribute to the oxygen barrier of  the epoxy.
> what kind of foam did boston  whaler use in their hull  construction?  My 
> friend has a bw dinghy hull  that weighs  about 300 pounds! Thats like 20 
> gallons of absorbed  water!   My understanding of closed cell foam is 
that if it 
>  is cut after spraying it  will absorb some, but i am not sure how  much. 
 I 
> think the Rhodes has the  good stuff in there like  the foam that floats 
> docks.(closed cell  polyurethane?)
>  Also is a pool noodle polyethelene foam? You can get that  stuff in  she
ets 
> and it would be nice to insulate the rhodes interior  hull  with.  It 
wont 
> absorb water either.
>  Thanks,
> Bob
> 
> 
> 
> On  Feb 13, 2012,  at 9:58 PM, Rob Granger <rgranger at sbc.edu>  wrote:
>  
>> Okay I didn't want to seem heavy handed when I stated   before that I was
>> "almost certain" that Great Stuff is closed  cell  because there is a 
lot 
> of
>> controversy on this  topic and to be fair,  not all spray foams are the
>> same...  but I'm a chemist and I felt it  was necessary that we get  this
>> straitened out since many of us are DIY   boaters...  so on the topic of
>> spray foam
>>  
>> Some  spray foams are latex and therefore open celled (DO  NOT USE LATEX
>> SPRAY FOAM ON YOUR BOAT) but Great Stuff expanding  spray foam is a
>> polyurethane-based foam and not a latex  foam.  So unlike the latex  
spray
>> foams it is *closed  cell*.   And you should not be  afraid of it  
absorbing
>> water.  It will (however) stick to the  hull  like ... well a 
polyurethane
>> glue (think Gorilla glue).   So  the bag idea is the way to go if you 
ever
>> want to get it  out again...  or line the area with visqueen before you
>>  spray.  I've used both  approaches and they both work fine...   I can 
post
>> pictures if  anyone wants to see the results of  the bag or visqueen
>> approach.
>> 
>> So to  clarify, polyurethane foam (Great  Stuff)  is *closed cell*... so 
 it
>> is fine to use on your boat,  even in low  spots.
>> 
>> The pink and blue foam boards at Lowes  and  HomeDepo are also great to 
use
>> for floatation  foam.  They are  *extruded* polystyrene and so they will 
>  not
>> fall apart into tiny  little balls that make a mess  everywhere... (Iike
>> cheap styrofoam  will).  I have  about six 3" boards cut up and crammed 
> into
>> my   MacGregor 22'.  And all of the little left over pieces are in a   
bag,
>> crammed into a tight spot and filled with spray foam (along  with  some
>> packing peanuts I got in Christmas boxes this  year).
>> 
>> A note on packing peanuts.  They're now  two kinds.  The  old-school 
kind 
> are
>> made of  styrofoam.  Those are fine to use on  a boat.  The other type  
are 
> "*
>> green*" and made of  cellulose.  The  cellulose peanuts will dissolve in
>> water.   Obviously  you do not want to use those.  It is easy to tell 
which
>> type  you have.  Drop one in a glass of water and wait a bit.  Or  you  
can
>> bite one  :-)
>> 
>> If you  are skeptical about the  closed cell nature of Great Stuff 
>  expanding
>> foam...(and it is not a  bad thing to be skeptical)  you can read about 
it 
> on
>> the Dow Chemical  site...  you wont hurt my feelings if you do... I 
promise
>> :-)
>>  
>> Here is the link to the Dow Chemical site
>>  
>>  http://building.dow.com/na/en/products/sealants/windowdoor.htm
>>  
>> 
>> my 2 cents.
>> 
>> ... the other  Rob
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