"RicodJour" wrote in message
...
On Feb 16, 9:27 pm, "MiamiCuse" wrote:
I posted an inquiry a few weeks ago about cutting old plastered wall that
is
has af gypsum lath as a double layer wall board.

I need to cut small holes on these existing walls for electrical outlets,
intercom units, and also old demolished walls that have unclean tearouts
at
corners that have embedded wire meshes. Initially I tried to use a
recipricating saw, no luck, then tried a rotaty tool and that worked fine
for like 5 minutes, then today I tried an angle grinder and it worked.

I knew it would be dusty, so I prepared and worn an extra layer of
clothing,
I put on a cap, a twin catridge respiratory mask, a eye protecting mask
and
went to work. It was DUSTY. When I cut the corner joints at the ceiling
there were so much dust flying it's like snowing right into my face. I
forged ahead and kept going. Soon I can't see the chalk lines I drew
because it was so dusty. I opened the doors and the dust started to
float
outdoors and it does not settle, it seems to float up.

I took my mask off and it has dust inside the mask, which was unexpected
since I was wearing it very tight. Next I have this gritty taste in my
mouth, did the dust get inside the respirator? I looked at myself and I
am
like snowman. I had some of this dust in my hand and it didn't feel like
dust it's like silt and it's all over me. I am starting to worry...does
plaster (built in 1972) have asbestos? It seems to have gotten inside
every
of my pore, I mean, I was wearing long pants outside and shorts inside,
and
I had my cell phone inside my short back pocket. When I cleaned up and
took
out my phone, I flipped it open and it opened half way, dust got inside
the
hinge and clogged it! How does it get past two layers of clothing?

I am only half done, after doing this for about six hours, but I am
hesitating to go forward without knowing more about this dusty silt and
if
it could be a health hazard. Is there a mask that can protect against
this?

You need to learn some dust control measures. When cutting anything
like concrete/drywall/plaster indoors, erect some temporary barriers
to close off an area. Plastic or drop cloths work well and they
should fit fairly tightly to the walls, floor and ceiling. You should
pick up most of the dust at the source, so tape a vacuum hose to the
tool or have someone hold it right next to the cut as you work.
Having a long hose, and the vacuum outside so the vacuum outlet is not
blowing stuff around is optimal. Just as critical is to rig up a fan
in a window or doorway blowing out. Close off around the fan with
cardboard so air turbulence won't bring the dust right back in. You
can tell if you've set up your protection correctly if the plastic
bulges towards the fan when you turn it on.

R

RicodJour,

I am basically doing cuts around the entire house so there is no need to
tape off or block off any specific areas.

I feel bad about having someone holding the hose next to it. 60% of the
cuts are actually above the shoulder heights some in the ceiling so it is
really difficult to get someone to be on a ladder next to you holding a hose
that high anyways I thought I would just "tough it out" but boy I did not
know it could be SO dusty.

The thing that really is challenging is that the dusty blurr up the eye
protector so fast that while it's cutting it's hard to see the chalk line I
scored.

The other problem I have is the plastered has metal wire meshes in it but
only around inside corners. When I cut that I am getting sparks from the
grinding wheel going across and I had to go real slow. I am concerned may
be I could be cutting an EMT pipe, or a AC condensation pipe or other hidden
metallic things, probably not but I don't like the flying sparks.

I am also predicting where my electricians will need cut outs and doing them
in advance, as I will not let them pound a big irregular hole in my wall and
celing anymore. Now I have an irregular size holes in the ceiling, in some
cases wider than the knock out circle size of the hi-hats, I am not sure
what to do with that, I don't have a hole saw that could cut this plastered
wall in perfect circle, and the holes may be wider than the needed circles.
I can't patch half an inch of an irregular sliver the remodel light fixture
needs to "clip" onto something. I think my only choice is to go to every
wrongly cut hole in the ceiling and cut a 16"x16" square hole, then put in
5/8 "normal" sheetrock and recut the circle?

Thanks!