Hi Vicki,
The error is entirely mine. My original measurement of the scrap I bought w=
as inaccurate. I don't know how I managed that. The actual dimensions of my=
green foam are 4 x 6.5 x 12 inches, which I work out to 1.5 pounds per cub=
ic foot. I'm confident in the weight of 125 grams as I was using an accurat=
e lab scale.
I haven't found an affordable scrap of anything more dense yet.
I purchased my green foam from Jo-Ann Fabric, a national chain.
http://www.joann.com/airtex-foam-chairpads-2-high-density/xprd780100/
It is made by Airtex, but I cannot find any specs for the foam on the Airte=
x site. Jo-Ann sell it by the foot in many thicknesses (only one example on=
line), and have off-cut scraps in the store.
I doubt it is ideal but it is all I can find around here.
John Crockett
Westminster, Vermont
--- In vickipowys <> wrote:
>
> Re the foam:
>
> I am puzzled, how can John Crockett's green foam be specified at 1.5
> pounds per cubic foot, if his scrap green piece 4 x 6 x 9 inches
> weighing 125 grams would, as a cubic foot, actually equal around 2.2
> pounds? (if I did my maths right :-)
>
> John's green foam piece was approx. the same weight-for-size as my
> grey piece.
>
> The original Crown SASS foam weighs the same as my grey piece.
>
> Rob Danielson was using 1.5 to 1.7 pounds per cubic foot density foam.
>
> I guess it is hard to accurately weigh a small piece of foam, so
> maybe some variations have occurred because of that.
>
> But if the weights of the smaller pieces was accurate, then this
> suggests John Hartog's link to the Grainger charcoal foam of 2 pounds =
> per cubic foot would be the closest match to the original Crown SASS
> foam.
>
>
> Vicki Powys
> Australia
>
>
>
>
>
>
> John Crockett wrote:
>
> > BTW, my green foam, at 1.5 lbs per cubic foot density, is similar
> > to the foam linked to on the diyboundarymic blog. So maybe it is
> > the "right" stuff. Just not identical to what Crown is using, which =
> > may be proprietary.
> > On 12/07/2012, at 2:08 AM, John Crockett wrote:
> >
> >
> >> Hi Vicki,
> >>
> >> The foam I am able to find locally is green (whatever that means!).
> >> It is called high-density foam (they also sell "regular" density,
> >> which is white), and although the clerks in the store had no idea
> >> about open or closed cell, it is absorbent like a sponge, so I
> >> guess it is open-cell. It isn't nearly as dense as I expected, less
> >> so, I think, than the foam mattress pad I mentioned. It is quite
> >> squishy. The 4" x 6" x 9" scrap I bought weighs 125 grams.
> >>
> >> Could I possibly have the right thing? I can return it if I bought
> >> the wrong material, but how can I tell? Does anyone know?
> >>
> >> Many thanks,
> >>
> >> John Crockett
> >> Westminster, Vermont
> >>
> >
> On 15/07/2012, at 6:05 AM, hartogj wrote:
>
> > The price $45.12 suggests the charcoal firm.
> >
> > I notice the charcoal firm at foamforyou.com is density is 1.5-1.7
> > lbs./cu.ft. The grainger.com charcoal sheet that I previously
> > linked to is 3 lbs./cu.ft. Grainger also lists 2 lbs./cu.ft
> > charcoal sheets, and 1.45 lbs./cu.ft balls and cubes.
> >
> > John Hartog
> > rockscallop.org
> >
> > --- In Peter Shute <pshute@>
> > wrote:
> >>
> >> It works ok as http://www.foamforyou.com/charcoal_foam.htm#
> >> Charcoal (I removed one space, hopefully the list doesn't put it
> >> right back again).
> >>
> >> There are two densities of charcoal foam, and that both are listed =
> >> as suitable for noise treatment and packaging. Which one?
> >>
> >> Can anyone see anything on the specs page that distinguishes these =
> >> from the other foams, apart from colour? They aren't the densest.
> >> Maybe low resilience?
> >>
> >> Peter Shute
> >>
>
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