I figure this is the best place for this question. I have a house built in 1921 and the walls are completely plaster and lathes. I'm going to begin upgrading all the electrical in the house (its knob and tube, and Nicola Tesla put it in himself :). Anyway, I know this question isn't an "electrical" question, but I would assume you guys have run into this before. Anyway, what is the best saw to use to cut into plaster and lathes for electrical boxes, and fixtures etc? Jigsaw, reciprocating? Router? Plus, should I be concerned about asbestos in the plaster? Again, another non electrical question. But for all you pro electricians, what do you do/use? Thanks!

A BIG variable is how sound the plaster is. I have seen it where the moment you begin to work on it it falls of in pieces, or even sheets.

My favorite method is a Rotozip.
First with a carbide bit to clear all the plaster/mortar. Cut around the outline,all the way through the material. Then just chip away the center.
Then a Saber bit for the wood lathe.
It does take a bit of practice to not let the tool get out of control, but once you get the hang of it it works awesome.

The plaster seems to be in good shape. I put an exhaust fan in the bathroom, and we used a dremel. It was a bit of a pain, plus it created a lot of heat when cutting the lathe. But the plaster stayed put. What is a Rotozip? Pardon my ignorance. And what are your thoughts about asbestos? Thanks!

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Originally Posted by KingsX

The plaster seems to be in good shape. I put an exhaust fan in the bathroom, and we used a dremel. It was a bit of a pain, plus it created a lot of heat when cutting the lathe. But the plaster stayed put. What is a Rotozip? Pardon my ignorance. And what are your thoughts about asbestos? Thanks!

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This is a rotozip:





If all possible asbestos should be removed by certified professional.

Just my .02

With plaster and lathe I would not worry about asbestos.

Then again, I never worry about asbestos.

You should be wearing a good mask anyway when using a power tool on plaster and lathe.

Plaster and asbestos are not two things that I think of at the same time. They didn't use asbestos in plaster. Horsehair more likely. More worrisome is the just plain dust in your lungs. Stan is correct. Put your head down and do it.

If you have the luxury of a helper when you do the cutting... have them hold a shop vac and follow the tool (rotozip) as closely as possible... as if it was atttached. This will keep all the airborn dust controlled.

A Die Grinder with a diamond blade works well, They are potentially dangerous, can get away from you if you don't maintain control.

Thanks a million for your help guys! The shop vac idea is a good one. My wife will have to help with that! The dust was a big concern because I have a one year old, and we can't move out while I do this. I have to do it over time. Anyway, thanks again guys!