In article , asalcedo.1zvwa0
@diybanter.com says...

What is the best way to repair hair line cracks on a lath and plater
ceiling?

The standard way, and what my decorator is doing at the moment, is
raking out, filling in and sanding down.

The problem is that after this is done the appearance is not very good
a couple of cracks have already been done at home. One can still see
the uneven celing and the protruding filler along the crack.

Also, I wonder if the cracks will reappear in a short time.

A different decorator mentioned that they would treat those cracks with
a thin painter's tape covering the crack and fine sanding the edges of
the tape.

When I suggested that to my present decorator, who seems to be very
experienced, he thought it was a bad idea, and mentioned that the tape
is mainly used in plasterboard.

Another question, is there a filler that is more appropriate so that
the cracks do not reappear?

If the plaster is uneven across the crack then the more plaster you cut
back, the less apparent the unevenness will be (but the more work you
have to do). If you apply the filler carefully it shouldn't need
sanding - build it up then scrape over with a straight edge (steel rule,
plastering trowel ...) so it doesn't stand proud. When it's dried off a
bit, skim with a thin coat just to fill any imperfections without
building it up any further. The original cause of cracking won't go
away unless you replace the ceiling, so it will progress. If the
movement is seasonal you may find that cutting back a minimal amount and
using a flexible filler will prevent the reappearance of cracks, but it
will still look uneven.