>Start small.  There are a lot of tricks to be learned.  And
>what worked for me might not work for you; experiment.

>-Bob

I understand your approach, Bob, and I agree with the
concept behind it.  This just seems like a lot of work that
can't be "undone" at all (or without a lot more work).  When
I've considered the expanding foam approach to insulating a
bus, my thoughts go back to the methodology used for packing
computers and TVs.  They apparently put a plastic bag in the
void, fill the bag with the form and let it fill the void as
it expands.  Then when it's cured, the whole piece of foam
is wrapped in plastic and *could* be removed as one
piece--not sticking to the inside of the sheet metal.

Two problems come to mind with this approach.  First, making
sure the stuff stays in the bag.  Second, making sure it
doesn't *bow* the panels.  Your advice to do small spots,
move on, and come back after the first area cures does make
sense.

Make no mistake, I have _not_ tried this in a bus (though I
use foam in architectural applications).

I would put a bag in a cavity, fill the bottom of it with
foam, and put the interior panel in place while the foam
expands and cures.  If the top of the bag hangs out at the
top of the panel that should keep it from falling down in
the cavity.  If there's not *too* much foam, it should
expand to fill the bottom of the cavity and cure.  Once it
has hardened, pull the panel off and put in more foam and
repeat the procedure until the cavity is full.  By the time
you get to the top, a twist-tie on the bag should contain
the last of the foam.

How all this would work in a *ceiling* application is more
sticky unless the bus is a camper or truck with panels
instead of a headliner.

What am I missing with this approach?

-Jim Bryant