First, thanks to everyone who weighed in on floation foam. sounds like the
blue sheet foam is what I need. It will be glued to under gunnels and
inside transom lockers, so expanding foam is ot an option.

Brian, Sounds like you did a lot of work. Thanks for sharing the process
and results. Blue foam it is, and a helluva lot less expensive then the
stuff I was finding.

Ed
"Brian D" wrote in message
...

Ed,

I'm sure that your local foam supplier (see the yellow pages) can get the
foam you need. I went to the one here, "The Foam Man" in Corvallis,
Oregon, and bought several sample of different types of closed-cell foam
to test them. I weighed each piece ahead of time (dry) and measured the
dimensions (rectangular pieces). Then I tied each one to a brick and
dropped it in a bucket of water where I left it for 8 months out in the
shop, filling as necessary to make up for evaporation. With all the dust
in the shop and mosquitoes trying to set up shop in the buckets, there was
slime and who-knows-what growing in it ...short of using seawater and
tossing in some oil and gas, I figured this was a pretty good emulation of
a typical bilge where you might add flotation. After the 8 months, I took
the blocks out, brushed them with a potato brush under running water to
remove slime, padded 'barely dry' on the outside with paper towels just to
get rid of sheet water on the foam, then weighed and measured each piece.

I forget now all the types of foam that I tested, but the clear winner
was closed-cell polyethylene (blue). They all absorb water over time, but
the blue poly only gave up 3% of it's flotation capability (3% of the
displaced water) and only swelled up about 3% in volume too. I followed
this test by putting the blocks of foam in Ziploc bags for a couple of
weeks, one end left open, to emulate a little trailer time for 'drying'.
The blue poly was still wet and there was lots of condensation in the bag
after a couple of weeks (not very good ventilation in/out of the bag), but
the poly had given up half the absorbed water anyway.

My conclusion was that the sealed-cell blue poly was an acceptable
flotation foam. In my case, I was looking for something that could be cut
to fit and installed, but could still be removed later on. Can't stand
that expanding polyurethane foam ...everybody that I know that has used it
in their boat has reported that it eventually becomes water logged and
sloppy. It is best used in compartments that normally stay dry, not wet.

Hope this info helps. For my boat project (see
http://www.reelboats.com ), I'll have cut-to-fit sealed-cell blue
polyethylene foam in the closed compartments, and will be able to remove
the foam via large rectangular deck plates installed in the bottom of
cabinets (not accessible to water on the deck ...deck plates leak). I'm
going to run a nylon strap or rope through the first block that goes in so
I can pull the blocks back out later on. It'll push the others towards
the deck plate as I pull it out.

Brian D




"Ed Lindsey" wrote in message
...
Hello,

Does anyone know of an inexpensive sheet foam suitable for use as
flotation? Possible sources in the western US?

Thanks