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Re: Foam toroid?



Original poster: "Jonathan Peakall" <jpeakall@xxxxxxxxxxxx>

Hi All,

>
> I was thinking the stuff in cans might work, but the chemical gives
> you a little bit of time before it begins to expand.. probably enough
> to get two mold halves put together and secured.. the can stuff seems
> to expand right away and I don't know how well it would fill a mold
> with minimal air gaps.. better be quick with the cans I guess.. ;)

One thing about the stuff in cans, for at least one brand that I have used
(can't remember the name) is that if there are not enough exits for the
foam, it won't set. I think it might be if there is not enough area exposed
to air that can release the solvent.

This may well not be true of all brands. A few years ago I was building a
beer machine, and needed to insulate the mash tun, which was a stainless
steel beer keg with the top cut out. I made a sheet metal cylinder 4" larger
in diameter than the keg,  and filled it with foam. Some of the foam
remained liqiud and did not expand. Eventually it dried, and then I drilled
a bunch of holes and blasted in more foam. With the increased number of
holes, it did expand correctly.

Jonathan
www.madlabs.info