THEY DON'T NEED TO BE DRY . MAKE SURE YOU HAVE THEM LEVELED BECAUSE THIS SETS UP FAST .
It can but be careful, there's no way to make any less than the entire bag at once. It'll expand to fill in the space and keep expanding until it fizzles out, same as those cans of expanding spray foam. If your space is smaller than the amount of space 1 full bag will fill, you'll have to wait for it to dry then saw or break off the excess.
yes put in trash bag or box but have it ready it starts expanding fast
if you are using two 60 lb bags per post i probably wouldn't use this your post must be heavy
I think I understand. You could do that but you'll find it will be hard to control the shape and spread. There are better ways to insulate - the best being top bury the line deep, below frost line which probably isn't very practical. even pipe wrap won't provide much protection outside at shallow depth