Sawzall or ? to cut thru old-style "plaster"

'allo,

I belong to a little brick bungalow in the midwest, built in '54, old-style plaster on steel mesh lath.

Recently found that kitchen and both drain pipes were sealed behind wall. Had to bust thru kitchen wall (tile and plaster) to replace drain pipe.

I found that the "plaster" was more the consistency and hardness of concrete than any plaster I seen before ...

The bath drain is overdue to roll over and die. The drain is in a partition wall opposite a bedroom closet. To gain access, I'd likely need to cut a large section of the closet wall out.

It's actually strange I've never bought a sawzall, but I've always got along with a little scroll-jig saw. Have built partition walls but never needed to rip thru old walls, chop thru roof, etc.

Anybody familiar with cutting the old style plaster?

Q1: Can I do it with a sawzall? If so what blade? Recall this "plaster" looks more like flogging concrete.

Q2: If Q1 = yes, would an 8 amp sawzall likely be adequate?

Q3: If Q1 = no, what should I use? Used a hammer/cold-chisel on the kitchen and it was a SEVERE PITA!

Any/all info/advice much appreciated.

Cheers, Puddin'

Pease pudding hot, Pease pudding cold, Pease pudding in the pot Nine days old ...

Reply to
Puddin' Man
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Much more familiar than I wish...

You *can* -- but it's going to make a hell of a mess, and you're going to go through a lot of blades. Not to mention shortening the lifespan of the tool, if the dust gets into the bearings or motor (it's very abrasive).

Yes.

Well, that's what I was going to suggest: hammer and chisel to go through the plaster, then a sawzall to cut the metal lath.

Reply to
Doug Miller

I would suggest a 4" angle grinder (rented) with a diamond tip blade and a shop vac. You can make a cleaner cut than the sawzall. A helper can vacuum along the cut line to reduce dust.

-- Oren

"Well, it doesn't happen all the time, but when it happens, it happens constantly."

Reply to
Oren

I do small cuts with a 1/8" carbide bit in my dremel tool. Cut the plaster layer away, then saw the wood lath.

Bob

Reply to
Bob F

I am now thinking maybe:

1.) Lay it out carefully with pen/marker (might be 9 sq. feet). 2.) Hammer drill with 1/4 or 5/16 " percussion bit every inch or less. 3.) Hammer and cold-chisel to detach "plaster". 4.) Recip saw to go thru steel mesh.

Is viable? I hate to knock huge jagged edges in the "plaster" which does not break predictably with hammer/chisel.

Thanks, P

Pease pudding hot, Pease pudding cold, Pease pudding in the pot Nine days old ...

Reply to
Puddin' Man

I think I remember suggesting a dry diamond wheel on a circular saw or an offset grinder back in the kitchen. They will make dust - wear a dust mask and safety glasses, isolate the space you are in with visqueen, clean up the mess when you are finished. What did you end up doing to repair the hole after you completed the pipe repair???

A reciprocating saw is an excellent tool. I believe in Milwaukee, but they are pricey for home use. They make a plaster/nail cutting blade, a carborundum blade (slow), and a dry diamond blade ($40ish). The jerking action of a reciprocating blade can loosen a lot more plaster than you originally planned.

For your application I would recommend a cheap, harbor freight type offset grinder ($10ish when on super sale) with an assortment of wheels that include weld cutting disc(s), grinding disc(s), flap wheel (for dressing steel), a wire brush or two(both cup and straight), and a dry diamond ($5ish on super sale). The dry diamond may smoke and burn a bit on it's way through wood lath, but it will work; no problem with metal lath.

They also sell dry diamond blades for 7 1/4" circle saws ($10ish). The first ones I bought were just short of $100, now down to about $50: but I have heard such good things about the Harbor Freight blades, I'm going to try them.

If your tub plumbing backs up to a closet or inconspicuous place, plan on creating a permanent access panel at the back of the tub with a screwed on panel that is trimmed out with door casing. ___________________________ Keep the whole world singing. . . . DanG

Reply to
DanG

My condolences. My home is built the same way. The plaster behind the expanded metal is even backed with pea gravel, to make 'improvements' just that much more fun. It's just amazing how much a 1 foot square piece weighs.

I had to make a number of cuts over the years, and what I used was a jigsaw, with the best blades I could buy at one of the big box stores. Drill a hole, insert the jigsaw blade and away you go. Eventually your progress will drop, because there are fewer and fewer teeth left on the blade. Time to change the blade.

Depending on how much cutting you need to do, it might be a better approach, as far as dispersed dust is concerned. You can find jigsaws that have dust catchers, or others that connect to a shop-vac type of cannister vac, to keep the mess under control.

With a grinder, wow. You'll need breathing masks!

Reply to
Robert Barr

For cutting metal (#4) would not a rotating disc cutter be more controllable than a recip. saw? (Also convenient for making little dints to get the chisel started.)

Reply to
Don Phillipson

Could be -- but it's still going to make a hell of a mess. I still say use a hammer and chisel to remove the plaster. If you're having problems with the plaster not breaking predictably, I'd say that's probably due to your technique. Don't try to chisel all the way through it in a single blow. Instead, score it lightly all the way around, just deep enough to get through the whitecoat. Then score it again, harder, about half-way through the browncoat. Finally, chisel all the way through the browncoat.

Reply to
Doug Miller

Before you try anything else, try this. Get a scoring tool that is used for scoring and breaking cementboard (e.g., wonderboard). The scoring tool is basically a piece of carbide, like those found on carbide-tipped circular saw blades, mounted on a handle. You drag it across the cementboard to score it. It is a hand tool that costs about $10, available at any big box type home improvement store. It works great on old, cement-like, rock-hard plaster. You just keep scoring until it digs a little channel all the way through. Then you can use a power tool to cut through whatever is behind the plaster, but without all the flying sparks, dust, etc. I have done this successfully with just your type of situation, to get at plumbing behind the plaster. It is easier, faster, neater, and less destructive than using a power tool to cut through the plaster. -- H

Reply to
Heathcliff

Well, I sho'ly get the idea. Sounds faster and cleaner, but with more elbow grease.

Not certain my chisels are up to it, 'tho. Maybe just put 'em on the bench grinder, sharpen 'em up a bit.

I had a little success using an old Skil Xtra tool (drill) on a hammer-chisel setting. Damned hard to control, 'tho.

Thx, P

Pease pudding hot, Pease pudding cold, Pease pudding in the pot Nine days old ...

Reply to
Puddin' Man

Why in the world pea gravel? Sho'ly not for insulation ...

I tried this in the kitchen. Bought the best blade the HW store had. Died a horrible death before progressing an inch. :-)

It's inna closet, so I'd need a mask regardless.

Thx, P

Pease pudding hot, Pease pudding cold, Pease pudding in the pot Nine days old ...

Reply to
Puddin' Man

That's pretty much it, yeah.

There ya go. Good luck!

Reply to
Doug Miller

Scoring tool for maybe $10. OK, that'll get me down to the HW or bigbox store.

Sounds viable.

Much thanks, Puddin'

Pease pudding hot, Pease pudding cold, Pease pudding in the pot Nine days old ...

Reply to
Puddin' Man

Too big, clumsy.

Hole was maybe 4" x 12". Very carefully fitted a 1-by -into- the hole, cut a larger piece of baltic birch plywood to cover hole and adjacent damage to tile, routed edges smooth, painted with Kilz to match tile, and attached a little handle.

A Milwaukee would outlive po' me by a factor of maybe 9. :-)

I screwed up the description: it's the lav drain, not the tub. Yeah, a removable panel will go in the hole.

I know where the local harbor freight store is, haven't been there yet.

Harbor freight stuff is Chinee? Anybody got an idea how long it'd last with infrequent use?

Much thanks, Puddin'

Pease pudding hot, Pease pudding cold, Pease pudding in the pot Nine days old ...

Reply to
Puddin' Man

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