Oscillating Multi-tool concrete blade

[drs3317]

I would like to cut an electric box into my concrete wall. I have an oscillating multi-tool I would like to use for the job. Would diamond or cemented carbide blade work for this or would I be wasting money on the blade?

 

[Kaizen]

Waste of money. They are for removing grout. Concrete blade on a grinder will do most of it followed by a chisel and hammer. Or just surface mount it with conduit and a metal box


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[PhysicsDude]

Waste of money. They are for removing grout. Concrete blade on a grinder will do most of it followed by a chisel and hammer. Or just surface mount it with conduit and a metal box

^ this. I'd drill 4 holes (1/4" or so) with a hammer drill in the 4 corners of where you want your box, cut the 4 sides with a 4" diamond blade, and then chisel and hammer the rest.

An oscillating multi-tool won't do hardly anything.

Are you installing an electrical box into a solid concrete wall, or cinderblock wall? Cutting a box into a solid concrete wall is quite an undertaking.

 

[drs3317]

Thanks for the advise guys. The wall is concrete. I really didn't want dust all through the house. But I will drill and use a 4" grinder to recess the outlet box.

 

[Kaizen]

You can opt to drill a bunch of holes. Knock out with hammer then clean up edges with a chisel. You have hollow block all the way from top to this location? Make sure you can get wire there before you start


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[Musicinabottle]

I've used a spray bottle and grinder before to knock down the dust. Be sure to get a masonry blade for the grinder.