You want foam in place polyurethane like this:
http://www.eps-systemsltd.com/

As you'll see, these guys are in the UK (our boat, Fintry, is there),
but finding a supplier over here should be no problem.

This is an absolutely standard application for bouyancy and for metal
boat insulation -- inert, water resistant, light.

You may find it easier to use urethane insulation from Home Depot (NOT
styrofoam) cut to size and glued in place with Great Stuff, but
foaming in place with a kit like the one above is the professional way
to go.

All sorts of cautions apply -- the stuff expands, so it would be easy
to burst a compartment while filling. It emits poisonous gases when
burning. Apply only in a cool, well ventilated place. Don't eat it.
Like Great Stuff, it makes a mess on your hands, unlike Great Stuff,
you can make a really big mess......

Jim Woodward
www.mvfintry.com


wrote in message ...
Looking for foam...
Great Stuff is OK but doesn't go far.
Anyone know of a low-cost high-volume foam?
A friend mentioned "2-part styrofoam" and said it was used in packing
boxes (shipping ups, etc).
Want to fill canoe and a 21' boat for floatation. Hardness would be
nice too - but mainly water-proof fill is desired.
Thanks,
Elliot