Was wondering if anyone had a good way of cutting outlet boxes openings in old plaster lath walls that will minimize any damage to the surrounding area?
be hating when that happens
r u a feckless dastard?
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I use a cut out tool like a RotoZip set to depth to cut through the plaster only, but a Dremel with a base works fine, too. Then I finish with a jigsaw with a medium blade and no orbital action.
I think it depends on how many you have to do and how fussy you want to be.
I have done a lot of these over the years and my preferred method is to take an old work box, draw an outline on the wall (using a torpedo level to make sure it is plumb).
Then I use a utility knife to break away enough plaster within the outline to find one full lath. Then I reposition the box and redraw the outline so I cut out the full lath and half of the one above and below the box.
After breaking out the plaster within the new outline, I take a sharp keyhole saw to cut out the full lath, then do the vertical cuts on the lath above and below. I score the horizontal cut line with a utility knife, and break off the piece I want to remove with a lineman's pliers.
Once the wire has been pulled into the box, and the box is placed in the wall, I drill pilot holes through the ears and attach the box (to the partially cut lath) with #4 screws, which are small enough so they won't interfere with the outlet cover. Then I snug up whatever type of wings are used with the box you have chosen.
I know this sounds time consuming, but if you use some more aggressive way to cut the hole, you'll often unkey the plaster and have lath flapping around -- which you then have to find some way to shore up if you want the box to be securely fixed.
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
that is the way I ave done all these many years, !Have you ever used the hangers for securing the box or a Gem Dandy box with hangers that snap in to the sides ?
"
<<"Have you ever used the hangers for securing the box .......or a Gem Dandy box with hangers that snap in to the sides ?">>Usually, I just use an old work metal box -- the kind with the wire clamps integral to the box, and the back corners cut off at 45 degrees. If by hangers, you mean the straps that slip behind the wall with two fingers that you then fold into the box -- I've used them for switches, but I haven't had much luck getting them fixed securely enough to work well for an outlet box. If that's not a "gem dandy", tell me more about them.********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Gem "dandy" boxes are a Brand , they are metal, no internal clamps, and come supplied with two clips, behind a paper insert inside the box.
they are made by the same company ( Gem ) that makes the type of boxes you have used. the box fits in the wall and you snap the two clips into their slots inside, the clips have long screws in them that are tightened to force the clips against the back of the lath.
the box is great if your opening is not against a stud however.Now ,the hanger you are having a problem with,
I grab the... end.. of the finger with a needlenose pliers ,pull the hanger toward me and against the lath and bend it over the lip, while I push the box against the wall, then flatten the little lip with a squeeze Is that what you do ?"
All of these are good suggestions. Aother option to consider is to cut the outlet boxes into the baseboards.
you may get some arguments here about that Tom,aound here the inspectors want them at least 18" off the floor."
I found a link,
http://www.garvinindustries.com/catalog.aspgoto their online catalog ,look for Sec.8 and scroll down to .(pg 44in the pdf.) .....the catalog page is a different number"
I use a RA grinder with a diamond blade...makes quite a dust cloud, so I use a shop vac while I'm cuttin'. Rotozip with ceramic tile bit to finish the corners.
I always try to make my cutout next to a stud so I can use a regular NM box and screw it to the stud from the inside of the box.
I mark the hole, drill two 3/8" holes with a masonry bit in opposing corners of my opening and do the cut out with a sharp wood blade in the sawzall. I cut vertically first, starting with the cut farthest from the stud so that the lath is supported well. Then make the cut next to the stud and the horizontal cuts. When you're done the blade is shot, but it works well.
For rock lath and plaster, I use the same method with a carbide grit blade.
Oh, and this takes practice and a steady hand.
If you haven't drawn blood today, you haven't done anything.
I find that and sort of power saw or router tends to break loose that lathe, and also makes a dusty mess.
I use a spade bit to make a big enough pilot hole, then I use a hacksaw blade (in a handle) with the teeth mounted to cut on the pull stroke. This cuts slowly enough so that not much torque is placed on the lathe, and cutting on the pull prevents the lathe from being pushed away from the plaster. It is also helpful to sink a drywall screw into the center of the lathe you are cutting so that you can grab onto it and brace the lathe as you cut.
With old brittle plaster, there is the danger that you will get cracks around the hole in the future. The hole tends to 'spread'. To prevent this, saturate the raw edges of the hole with white glue or Weldbond. The plaster will drink in a number of coats, and this will consolidate it.
Another reinforcing trick is to hot melt bits of lathe or popsicle sticks to the back of the lathe around the hole. You can use white glue or caulk instead, but hot melt is faster.
After I set the box, I caulk around the edges. This adds a lot of strength (and air-sealing).
But..no one mentioed this nifty gadget..
http://www.mfg.mtu.edu/cyberman/machining/non_trad/waterjet/#Type Spheramid Enterprises Architectural Woodworks
yeah baby...........that should keep the dust down"
I have an old brick house with lots of plaster/lath on the interior walls.
I use two utility knives... One with a strong "backbone" meant for hammering and one with a very new blade in it. I use the first knife to hammer and cut through the plaster along my pencil line. Use a small, lightweight finish hammer so you don't shake the wall too much. Don't go too deep... keep at an angle and try to guage how deep the plaster is and stop these cuts just before the lath. Remove the plaster and expose the lath.
The sharp knife I use to score... score... and score again... the lath, until I can simply snap it back and off with my hand. Some walls and more brittle than others, so check and make sure your location for the new box is solid. If it's loose, think about moving if possible to a spot where the plaster "keys" and tight and solid.
On occasion, I've had to install a 1/4 thick backer on one side or the other to firm up the plaster and lath. Predrill the plaster... and simply screw through the lath and screw the backer up snug. It's usually enough to tighten up an old work box with clamp.
--Jerry
What I find works well for cutting the plaster is a diamond blade hand grout saw, used for tile work. It cuts so easily that for something as small as an electrical box, it's easier than setting up with a power tool. It gets you clean square corners, and it lets you feel when you've hit the lath.
-- J.S.
I use a painfully slow method that is pretty safe and doesn't make a lot of dust. I'll gently chip the plaster away with an awl and cut the lathe with a utility knife. The sharp point of the awl puts very little pressure on the plaster if you go slow with shallow bites yet takes out larger chunks as needed. Having done a couple dozen boxes like this with no plaster cracks, let alone chunks falling out, this is probably how I'll keep doing them although it does feel odd using the round awl to make square holes.