Originally Posted by Chris Bacon

asalcedo wrote:
Chris Bacon Wrote:
asalcedo wrote:
What is the best way to repair hair line cracks on a lath and plater
ceiling?
[ snip squeezy PVA ]
That sounds like a cracking way to treat cracks.

It glues the whole lot back together, and stops the edges
of the plaster gently rubbing together and dropping sand/lime
down the crack, where it collects and bulges out your paint/paper
or displaces your carefully applied filler.


I have a pointing gun that can be used with softer materials, like
grouting for tiles, will this work as well?

Don't think so - the idea of the lagging is to seal against either
side of the crack so that PVA mix is forced up. You squirt some in,
move along the crack, squirt more in, move... (repeat).


The system with the squeeze bottle and pipe lagging you describe is not
that clear to figure out.

See attempted pic. below.


So, if I get it correctly, the idea is to get PVA glue inside the
crack. Right?

Yup - it works well as the PVA:water mix is very runny, goes right
into the crack, and gums it up good'n'proper, if there's dust or
sand in there it sticks that too and makes an even better repair.

Will this not stain or leave a mark along the crack?

You should wipe a sponge along to collect drips before they set
to form hard lumps of PVA, then you can wipe some filler on if
needed, with a filling knife. It doesn't stain.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/ - crack.
xxxx xxxx xxxx / xxxx xxxx xxxx - Plaster & lath.
________________/________________
|##### #####|
|##### #####|
|##### #####| - Foam lagging taped
|##### #####| around and
|##### #####| tied onto
:|#####| |#####|: - squeezy bottle neck
:|#####| |#####|: with string.
/ \
/ \
/ \ - squeezy bottle.
/ \
/ \
/ - - - - - - \
| |
| - - - - - |
| PVA/water |
| mix in |
| - - - - - |
| "Fairy" |
| bottle |
| - - - - - |
| |
|_____________|

Push the flat end of the cut off foam lagging against the ceiling
over the crack. Inject PVA:water mix by squeexing. Move along
crack, repeat 'till done. N.N. wipe off PVA drips. Don't use the
PVA mix thick on hairline cracks, it won't penetrate.