RE: Notes-Questions-Article-All

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Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-compaq-dot-com>

The Great Stuff foam cures by means of a chemical reaction with water vapor.
Since I knew that a sealed aluminum corrugated duct is impermeable to water
vapor, I added a couple teaspoons of water and coated the interior surfaces
prior to injecting the Great Stuff.  I had no problems with curing, just the
lack of visibility of fill status and extended expansion.

Gary Lau
MA, USA

 -----Original Message-----
From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent:	Tuesday, September 04, 2001 3:51 PM
To:	tesla-at-pupman-dot-com
Subject:	Re: Notes-Questions-Article-All

Original poster: "jpeakall by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jpeakall-at-mcn-dot-org>

Daniel,

It may take months to dry. I made a double walled mash tun (think a big
thermos) for brewing beer. When I filled the air space, I made LOTS of holes
and so on, but the foam couldn't dry properly, and left soft spots. Drilling
into these holes many days later yielded liquid foam that even when left
outside would no longer expand when it dried. I later tore it apart (months
later) and found that the liquid had dried, but not expanded, leaving a
swiss cheese effect. It seems there is an effective depth or volume that one
can foam at one time. I think if I had layered it over a period of days it
might have worked.  I used "great stuff" foam.

YMMV,

Jonathan Peakall
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From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, September 03, 2001 8:26 PM
Subject: Re: Notes-Questions-Article-All


> Original poster: "Daniel Barrett by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <dbarrett-at-clearcube-dot-com>
>
>     I tried using the foam last night, but I filled the torroid about 3/4
> full of styrofoam shipping peanuts to give the foam something to expand
> into. The outside seems nice and firm today, but I don't plan to take the
> duct tape off thats holding together for a week or so:) The little blob of
> foam I stuck on the table outside is still not set after 24 hours, so I
> guessing it will take a while for this stuff to cure.
>
>
> > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Hollmike-at-aol-dot-com>
> >
> > Well, It would seem that it could be done, but perhaps a bit more
thought
> > would be in order before trying such a thing.  I joined the ends of my
> toroid
> > by affixing tabs(cut from roofing flashing) to the inside of one end
with
> > epoxy and then to the other, once the first step dried well.  I think it
> made
> > a very strong joint.  I also applied a bead of epoxy to the seam itself.
> I
> > would almost guess that the toroid would split at one of the
corrugations
> > before parting the ends.   Perhaps one could estimate the proper amount
of
> > foam by the time that the valve is opened or something.  Perhaps even
the
> > location of the injection hole might be a factor.  I would think that
the
> > hole should be close to the seam so that part of the foam would set
while
> the
> > rest was still expanding.  I dunno.  I am still just musing.
> > Mike
>
>
>
>
>