"BETAC-T" wrote in message
. ..
I have an old house with wood lath and plaster walls, and I need to cut
out
a lot holes in the walls for light switches, electrical outlet
receptacles,
etc.

Here is what I am doing now, and here is what the problem is:

I am just cutting them out by hand, one-by-one, using hand-held wallboard
saws, etc. The problem is that it is hard to keep the underlying wood
lath
from vibrating and causing a wider area of plaster to crack and break out.
I have tried making sure each hole is adjacent to one of the studs so at
least one side of the hole has wood lath that is nailed down to the
adjacent
stud. And, I have tried being very careful, cutting out a little,
reaching
in to hold the rest of the wood lath stable, and then carefully cutting
the
wood lath. But it is still a mess, doesn't work very well, and takes a
long
time for each hole.

I don't think using any kind of powered reciprocating saw or saws-all
would
help and probably would only make the lath vibrate more and damage a wider
area of plaster than using the by-hand method.

The problem seems to be the reciprocating action of the saws, so I keep
thinking there ought to be some kind of small circular saw that could be
used and plunged into the wall to cut the lath without vibrating it back
and
forth. But I don't have, and haven't seen, a circular-type saw that would
be small enough to do this.

I have thought about buying one of those drill bits that supposedly can
saw
sideways to cut holes in walls (which I saw on TV), but I haven't found
anything like that in any stores and I have a hunch they don't work anyway
(which is probably why they are only on TV).

So what the heck do professional electricians do? I keep thinking they
must
have a tool or know of a trick to make this easy, especially since they
don't want to damage their customers' walls when putting in new outlets,
etc.

Any ideas? Thanks.


Cutting into wood lathe and plaster is never fun. I have always warned the
customer that there may be collateral damage. One thing that I do is put two
inch masking tape around the hole before I begin to cut to help keep the
plaster from breaking off on the surface. Unfortunately once you fully cut
the center lathe it is completely unsupported and leaves that portion of the
wall susceptible to future cracking.

I have thought of possibly cutting out a portion of the center and upper or
lower lathe. Then insert another vertical piece of lathe off to the side
and screwing through the wall to tie it into the upper, center, and lower
pieces of lathe. In theory this would keep the existing lathe stable. I
have never tried this though, but if you do please post back with your
results.

As someone else mentioned, I also score the plaster, but I have been using a
razor knife which dulls the blade quickly. The carbide scribing tool sounds
like a good idea instead.

You can try a Rotozip. I think that they make carbide bits for plaster.
The high speed bit may cut through with less vibration than the forth and
back motion of a hand saw.

For round holes for ceiling fixture boxes I have used a 4" carbide tipped
hole saw with very good results.

I have been fortunate lately in that many of my customers with wood lathe
and plaster have decided to remove it all. It makes it easier for plumbing,
electrical, heating/air conditioning, insulation, and to find and repair
structural problems.

Makita used to make a small diameter cordless circular saw and diamond
tipped blades to go with it. I haven't looked at their product line lately
to see if it is still available. I have one and used it on bigger holes for
bath fans and such. It does a nice job, but there is a tremendous amount of
dust as a result