On May 28, 8:38*pm, "John Grabowski" wrote:
my house has walls that are very thick and heavy. Cutting electrical
outlet holes and ceiling holes is very difficult. Using a saws all
with a big tooth demolition blade, I get maybe 20 inches before the
blade is flat. Ceramic blades are much worse. Am I doing it. Right?
I find finer tooth blades are worse.
Greg
What is the material that you're cutting? Other than outlet boxes,
what
are
you cutting on the ceiling?
I have cut ceiling recessed lights and an attic entrance. The round
holes need a smaller blade which goes bad fast, there is no lath or
metal or wood. I'll see if I have a piece to take a photo.
Greg
I think what you have, is rock lath plaster, it's like a layer of 1/2"
sheetrock with holes in it, that's plastered over. The plaster keys into
the
holes. It winds up about an inch thick, and is often very hard. I
usually
cut outlet holes in that with a hand keyhole saw. It's work, but you're
getting a clean rectangle with no big chips. For the recessed lights,
Lenox
makes carbide hole saws that work great. The only down side is the dust.
I
cut a basketball in half, and drill a hole in the center of one half,
slide
it over the hole saw, which helps to trap the dust and plaster
particles.
Picture".........
http://zekfrivolous.com/wall/wall.JPG
Greg
Looks like rock lath, but I've never seen the plaster coat that thick. It
looks more like cement than plaster. OK, so you live in a bunker. If
you're
near tornado alley, that's a good thing. Look at the bright side, when
you're done with this project, you'll have the biggest biceps in town.
I'm near Pittsburgh. House built around 1953. We have had tornados
lately. I also have basement. I can see where the walls have bent the
10 inch joists down over the years. Another trouble house was built
with a main bean of 4 8X2 s. I reinforced that. I'm still leveling.
Greg
*That is a heavy duty wall. *I suggest a RotoZip tool with maybe a cement
board bit or possibly a diamond bit. *For a quick square cut,
not-too-accurate of a hole, an angle grinder with a diamond blade will be
fast, but dusty. *I have a little Makita cordless saw. *I can put a 3"
diamond blade on it for cuts such as yours. *The 9.6 volt battery doesn't
last too long though.
The hole saws that RBM suggested are perfect for recessed lights. *They are
available in several sizes to accommodate different manufacturers. *You can
also get tungsten carbide hole saws the same size as round electrical boxes.
Check McMaster.com- Hide quoted text -
- Show quoted text -
I live in pittsburgh too, the plastrer can be unreal hard.
Because of this I mark the wall and use a drill, first drill holes at
corners, then use the bit to drill to drag the bit and connect the
holes.
Its not pretty but far less dusty and no constant replacing of blades