Anyone have any tips for doing cutin work in lathe and plaster? Jigsaw and sawsall seem to be a sure way to end up needing a patch. Skill saw works well but is a huge mess. Hand saws are really slow. Anyone got a tip?

Try a roto zip

I actually tried that but burned through a tile cutting bit with my first hole. Is there a bit you would recommend?

I use a 4" side grinder with diamond blade or a rotozip most of the time. If the wall has wooden lath I cut the plaster then change blades in the roto zip and cut the wood. Running the shop vac helps keep the mess down some. If I need to do a clean job (no dust)I use a hand saw, slow but less messy. A sawzall tends to grab and pull the plaster loose and make cracks. Rod

First you have to accept this type of work in itself is really slow. What works for me is lay out your cut and then chip out the plaster with a plaster removel tool. (screwdriver) Then cut the lath with a sharp hand saw or a roto zip with a wood bit.

Sawzall or jigsaw with a carbide blade.

Dnk.....

I found that the cordless saws like my Makita 4" 12volt make a nice clean cut and the blade spins so slow that the dust just drops to the floor without spraying all over the room. Prior to this I was using my 4" mini grinder with a "dust muzzle" attachment. This was a neat little plastic guard that hooks up to a 1 1/4" vacuum hose that sends most of the dust to your shop vac.the dust muzzle is at: www.dustmuzzle.com
Good luck,
Harold

I know the problem with the sawsall is the blade grabs on the backing boards then the plaster comes loose all over. If used a sharp blade is a must. You can kill 1 normal blade per hole.

Screw driver chipping out works.

I had luck with a hole saw. Several cuts and then chipping out the corners for a box.

Those roto zip blades allways burn up on me. Maybe I have the wrong type.

I hered the idea of screwing a piece of pllywood all around the hole to be cut. This is to keep the lath from comming loose.

Tom

I use a 3 3/8" cordless makita saw with a diamond blade for the plaster and a sharp blade in a jigsaw for the lath. The jigsaw can be handled with one hand and the lath stabilized from bouncing with my other hand.

steve

If the plaster has metal lath, a hacksaw blade is the way to go. It's helpful to use the blade so the teeth cut on the push stroke. You can get a hacksaw-blade holder that allows using the blade like a keyhole saw.

A hacksaw blade can be used for wood lath, too. The best way to loosen as little of the lath as possible is to make the vertical cut farther from the nearest stud first, then the cut closer to the stud; the closer, the better.

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

I usually just use drywall compound or spackle.

ETA: I have heard about a mix of plaster and drywall compund that's supposed to give a "closer to original" finish, but I've never used it.

[This message has been edited by DougW (edited 05-15-2005).]

I usually find the location for the box, trace it out and then drill a series of holes at the edge.....about 3/4 I bought a fine tooth wood saw at the Depot and will cut the remaining lathe while holding the lathe with Channel Locks to keep the damage to area plaster at a minimum....the key is a real fine tooth to the saw, more aggressive than a hack saw, but less than a jab saw.......it is slow, but keeps the plaster as good as it can be.

Never had much luck with the roto zip.....

[This message has been edited by GovtVoltage (edited 05-15-2005).]

I always use a jigsaw with lath. First, I clear away the plaster with a screwdriver. I then start on the lath. The trick is to not cut all the way through the lath vertically (that'll tear open the wall). I use plyers to take out the lath that has been cut 90% of the way through.

BTW, some plasterers were better than others. If they didn't mix it right, it crumbles or comes off in sheets. Have a long discussion with your client about the possible need for a decorator.

Dave

Bash large hole stud to stud with hammer! Kick debries into corner.

Install new work box, tell client you'll be back when its ready for trim.

Or why wait, trim it then...