we've done some cement bands around windows and doors. a couple of them had gone past it a bit when we were cutting them out and were quite brittle and have chipped on the edges. Does anybody have a good suggestion of a filler that will stick and also be able to be sanded to repair the edges. I'm thinking give the bands a coat of paint first to seal then use that pink car filler called isopon easy sand(remember doing some bodywork years ago on a cavalier and thought the filler was nice and sandable). Any tips guys?