On Sat, 20 Sep 2008 20:46:31 +0100, wrote:

Caulk is flexible enough to withstand the movement without cracking -
but very difficult to sand, so you have to get it smooth when applying.

I'd agree about the sanding attributes of Decorators caulk . But how
about filling to some degree with some sort of filler then using
plasterboard jointing cement ( Gyproc is one make) to complete and
that gives a very smooth finish

Trouble is jointing stuff sets hard and the movement will crack it. You
want something like decorators caulk that stays flexible to take up
movement without cracking. As Dave says it's next to impossible to sand
caulk but it is easy to get a smooth finish with a wetted spatula. I
wouldn't use a finger on a crack as fingers are too soft and will make a
slight U along the line of the crack.

--
Cheers
Dave.