Paul Franklin wrote:
{snipped a bunch of a very good post}

Seal any holes or gaps in the formwork with caulk or foam. The stuff
doesn't seem that runny, but I had a small gap and it slowly seeped
out as it was setting and I ended up with a depression in the surface
next to the gap. I also had a small hole in the underlying concrete
that I assumed was shallow, and a surprising amount of compound ran
into it, leaving another depression.

I use tape to seal off those cracks and gaps. Very quick, no setting
up time like caulk.

R