Posted for "kevin lane" <n3773@attbi.com>:

save yourself a lot of work and use light-weight joint compound topping
mix(sheet rock putty).  it sands significantly easier than the std.
compound.   DO NOT use plaster of paris or Fix-All, VERY difficult to sand.
note, too, that the spray foam comes in two densities, high and low
expansion.  it is definitely worth wearing gloves when shooting it.
kevin