In article ,
John Rumm writes:
Andrew Gabriel wrote:

damp). Note that mortar takes weeks to reach final set, and the
surface (if you are leaving the mortar exposed) is easily marked
during this period.

and if you are not leaving it exposed, then scratching it up a bit
before it sets can help provide a key for the skim coat...

Yes. Do this for all coats except the final one. Do it before it
reaches initial set.

--
Andrew Gabriel
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