Cutting plaster with a Multimaster
Just wanted to post some experiences…
First, I drilled holes at the 4 corners with my carbide “drills thru anything” drill bits (yes, they do). The hole size was 6″ x 10″.
The segmented grout removal cutter does an awesome job at cutting plaster. the process is quite dusty, though.
The cutter does not cut the whole thickness. I needed to finish the cut with a wood/nails blade. Yes, the blade was trashed in the process. Yes, lots of dust. The diamond blade looks a little bigger in diameter and it might cut the plaster in one pass.
I was able to remove the plaster plug in one piece before cutting the lath- the vibrations likely broke the plaster free on the back side of the lath. This plaster did not have the metal chicken wire in it.
The hole was located with one side next to the ceiling framing.
A variable speed Multimaster might do a better job at prolonging blade life/reducing dust.
Yes, the Dremel blades fit the Multimaster with the round arbor.
I did not find the star adapter necessary while using “new style” MM blades on the older tool.
Replies
I've been wondering about using the carbide 'scraping' bit for cutting plaster. Have you tried that? Still dusty I'm sure.
Nope, have not tried that.
I was pretty impressed with the grout cutting tool.
Yeah, I trashed a wood-cutting blade on plaster one time. Makes for a damned expensive hole ! Hadn't thought about the grout blade. Thanks !
Greg
I use these: http://multiblades.com/specialtyblades.html
Works great, but dusty
Has anyone tried the new Milwaukee cordless "mini-hacksaw" on plaster/wood lathe? It has a 3/4" stroke on the blade. I was considering buying it for that purpose.
http://www.milwaukeetool.com/webapp/wcs/stores/servlet/product_27_40028_-1_748104_199637_192137
Ive used the cast iron tub demo sawzall blades from lenox on plaster walls with good success. The stuff with two layers and the real sandy basecoat.
Still really dusty unless youve got a helper to hold a vac.
ps. didnt work for beans on tub though,
Mike
How would it be any different than a regular Sawzall?
Harder blades!
The "Mini Hack" uses the same motion to cut as a regular Sawzall.
The carbide grit blades will cut the plaster fine, but the tool is still the issue.
I would make use of a jigsaw before using a Sawzall again on plaster.
i would never use a saws all even with a good blade. I would be afraid of all the plaster coming down!
Any form of reciprocating action risks shaking the lath and breaking the keys on the plaster.A rotary tool or a MM. The only ones I'll consider.
I agree a rotary tool is ideal. However, If you cut a hole in the wooden baseboard and then work on the plaster behind it, you need a very long rotary bit (for a my cut-out tool). To date I have used a plunge router, but the bits get very dull after a few.
I was hoping the quick speed of the mini hack-saw would not grab the wood lathe and shake it apart.
thanks for your suggestions
I use MM with the cheap HF blades!
Drill a pilot hole. Use a Hitachi, Bosch, or Remgrit grit blade in a jigsaw with no oscilation. Just go very SLOW. Having a helper hold a vac will help. If you go slow enough it will cut through the plaster and the lathe with shaking everything apart.
IF the hole itself doesn't need to be too precise, I've doneit with a sawzall after screwing a board to the wall on the side you want to save. Keeps it from shaking apart. Done it with a skill saw too, but that really sends the dust flyin'Steve
Plastic electrical conduit can easily be heat-bent into a very efficient dust-nozzle for your MM.
I took a length of 3/8" dia. steel and bent it into a sharp Vee-shape.
Then I used a combination of heat from my oven (don't tell DW!),and a heat gun to soften some 1 1/2" conduit until it was malleable.
At that point I shoved the steel Vee into its mouth to create a slot-shaped vacuum nozzle.
It fit over the circular blade I was using, eventually cutting slots in both ends of the intake orifice, but sucking up 90% of the dust when attached to my (first choice) Wap, or (second choice, noisier and less powerful) Festool vacuum.
BTW, the real problem with most of these plaster-cutting jobs is not the plaster dust, but the lead-paint-dust generated.
Given that a flake of lead paint the size of your thumbnail is enough to cause a measurable loss of IQ if ingested, doing the math will tell you that a 6"-long circular-saw cut, or maybe a 1'-long MM cut, will generate this amount of dust.
After that, it's up to you to see how much of that dust you, your clients, and their kids suck in.
AitchKay
Good point about the lead dust issue. Didn't fully consider that.
I do a lot of renovating of old lath-and-plaster walls: the kind with horsehair in the plaster. I find the best tool for cutting out pieces, or opening up cracks, is a 3/8" cruddy old concrete drilling bit and a drill motor. I run that around the piece to be removed, and along cracks to dig them out. If you have a shop vac, put that in your other hand to catch a lot of the dust and old plaster.
Bob Chapman