ECN Forum Forums General Topics of the Trade General Discussion Area Cut-in Work in lathe and plaster

I find that a screwdriver works the best. As said before it takes a little time but the time that is saved in not have to do any patch work makes up for it. Draw the outline, go around the outline with the screwdriver, the plaster will come out, then I drill 1/4" holes in the lath with a drill, then connect the holes with my fat max key hole saw. You can skip the drilling and just use the fat max

Thanks for all the replys guys, some good info there.

Dave

I use a Roto Zip with a tile blade for the plaster and a wood plabe for the lathe. I can get a few rooms doing it this way. With the vac on it the mess is small as well.

One of the tips I saw in a Fine Home Building (FHB) tips & tricks book to minimize plaster "shake-off" -

Find the studs on either side of the bay you're cutting.

Use long drywall screws to secure 1" x 3" 's to either side through the plaster and lathing. Make sure they extend at least 12" past the top and bottom of your intended cut area.

Make your cut. The one by's will keep the lathe from popping free from the studs and "earthquaking". Stay close to the temporary plates to minimize movement of the lathing.

I've found that using a sawzall with a carbide grit blade lasts a lot longer than the bimetal wood or plaster blades on drywall and plaster.

[This message has been edited by DougW (edited 05-09-2005).]

Doug, What do you do with the holes in the wall the screws leave?

I don't know if this tool would work effectively on lath & plaster, but Makita make a twin-diamond blade chaser ( 1/4"- 5/4" wide, 1/4-7/4" deep). On Makita's UK website the tool number is 'SG150' (it's 110v), but I was unable to find it on the US website. I've also seen a smaller version, Makita 240v 'SG1250' , on the Screwfix UK website. Other makers should have similar tools.
Alan

Just did a bunch of cut ins through plaster on top of button board (drywall with holes all over it). Total wall thickness of 1 inch.

I used the 1/4 inch zip bit for plaster I think. I tried the 1/8 inch and burned up in no time. It has the knurling on the business end. I went through the plaster first, then extended the bit to get through the drywall. It is a lot easier on the bit that way. My helper stands with the shop vac to follow the roto zip. Not much mess.

When I have to work in lathe and plaster, as in installing an old work box, no matter how I cut it, I try to find the best way to wind up with both ends of the box on a lathe, otherwise it seems like I can't get the box or device anchored securely. I've begun to shy away from powered saws for this as it seems to do more damage than just going slowly with hand tools. Sometimes just drilling a bunch of holes around the outline of the box and filing with a sheet rock file works best.

For plaster and lathe you need a gentle touch and a few prayers thrown in for good luck. (LOL)

I use the same method as rusty on plaster. I drill a lot of little holes on the outline with a high-speed drill, no larger than 1/4". Then I follow it with a hand drywall saw, cutting slowly only on the push & not dragging on the pull. As harold says, gently with a prayer, but it usually works well.

I used the same method cutting expensive wood cabinets.

Dave