Is it just me? Am I too picky?

EBEBRATT-Ed

@Gordy, I have a Dremel I use. Probably not as good as a Rotozip but it's gotten me out of a few jambs.

ChrisJ

I have several ideas I'm going to try out.

I plan on gluing the lath to the framing around the box a week before cutting it which will help a lot.

Gordy

A muti tool works great also. On the wood. The thing I do not like about them is the blades are not very durable, and they are expensive.

ratio

I found a metal Porter Cable (IIRC) blade with carbide teeth that worked as good on the fourth cut as the first. Pricey, but the teeth are still on it...

ericmmff

Don't worry about the damper plate ,it will never be fully closed. Air flow can be adjusted at the diffuser. Silicone and or tape the flange to the duct. The flex duct is pulled all the way over the take off cover the damper platform mounting holes making that a non issue.
As for the lathe and plaster,circular saw with trim blade. Plunge cut from below using painters tape to protect paint. A small pilot hole can be drilled to check for optimal cut. If possible try cutting lath completely, not ripping any piece. Cut slowly. Vibration is you enemy reinforce top side if necessary Drill pilot hole for any lathe that needs to be attached. Safety glasses and dust mask.
Go get em tiger.

Gordy

In this case when doing overhead cuts. I prefer a light tool that makes the least amount of dust in the living space. My rotozip has a vacuum attachment is light, and easy to maneuver. A circular saw overhead is dangerous, messy, heavy, and awkward.

I would use a 4" grinder with a masonary blade before a skilsaw. For the plaster. Very dusty though.

Adjusting the airflow at the diffuser is not optimal as it affects the throw. Plus now you allow all the energy to the ductwork that is being dampened. Better to do adjustments at the takeoff damper.

ChrisJ

@Gordy,
I've been told using the damper on the diffuser also creates noise.

Curious how a 4 1/2" grinder would work with a vacuum attachment. I had been eyeing that up for a while.

Gordy

I have no doubt it would work except the lath. It might get the lath except masonary blades tend to burn the wood. You could have a second individual hold a good shop vac up by the grinder while cutting. The wifey could participate

ChrisJ

Gordy said:

I have no doubt it would work except the lath. It might get the lath except masonary blades tend to burn the wood. You could have a second individual hold a good shop vac up by the grinder while cutting. The wifey could participate

They have a toothed masonry blade.





Here's the dust collector attachment.

Gordy

A sawzall will rip the lath loose.

Yeah they have teeth, but they really lose performance on wood. A grinder runs at a much higher rpm.

ChrisJ

Gordy said:

A sawzall will rip the lath loose.

Yeah they have teeth, but they really lose performance on wood. A grinder runs at a much higher rpm.

One of the ideas is to use the sawzall from the top resting the foot on the framing. It would be pulling the lath into the framing rather than pulling it away.

A fine tooth metal blade and some patience may work very well.

Gordy

The dust collector attachment is nice. Except how it affects visibility, and having a vacuum hose hanging off the tool. That's why I suggested a second person with a shop vac. Give the user a little more freedom of movement. Then the wifey is responsible for the amount of dust she did not catch

ChrisJ

Gordy said:

The dust collector attachment is nice. Except how it affects visibility, and having a vacuum hose hanging off the tool. That's why I suggested a second person with a shop vac. Give the user a little more freedom of movement. Then the wifey is responsible for the amount of dust she did not catch

What planet do you live on?

Gordy

lol. Hey it's always worth a shot.

Gordy

If you have a multi tool, or a buddy that does they are pretty sweet to finish the lath off. You will probably score the lath pretty good with the grinder.

ChrisJ

Also @Gordy this is one of the reasons I want to glue the lath to my new framing around the opening. That will stop the saw from moving it around.

Gordy

Here is the scenario. You'll get into the lath with the grinder. It will smell like burnt wood. The wife is going to smell it thinking your going to burn the house down. You will reassure her that is not the case, and she won't sleep all night. Mean while neither will you.

ChrisJ

Gordy said:

Here is the scenario. You'll get into the lath with the grinder. It will smell like burnt wood. The wife is going to smell it thinking your going to burn the house down. You will reassure her that is not the case, and she won't sleep all night. Mean while neither will you.

Gordy

That will help. You will still have a lot of vibration that will transfer. What kills plaster integrity is busting the key loose on the back side of the lath. The plaster that is pushed between the lath.

ChrisJ

My concern with a Rotozip is the dust.
How well will a dust attachment handle that?

Gordy

Meh it's not 100%. Mine came with the dust attachment. Overhead is a little different. You need high suction. Gravity works against you. Dust laying around the cut surface verses falling from the cut.

None will be 100%. Well unless you spend dollars.

clammy

It.s been a while since i ve posted but u ain t to picky u just want it done to the best and ur willing to do the reasearch kudos ,as for cans to old plaster cielings what i usually do if there s alot of uneveness at where ur can meets the attic side of the cieling is to have a insert piece made tht slides inside ur can and leaves a 3/4 inch flange in ur living area also u can just chip out the extra plaster thats on the attic side .i know most guys just screw the can to a beam but with some measuring and some drive materal u can space ur can in between ur framing that way u can insulate ur can completely .After all the years of retro installs i have found that metal blades on a saw all work best in mimizing the vibration and cracking the plaster .For dust control just get some one to help you and have them hold a cut box under ur cieling box cut outs that a standard for doing retro cut outs .Hope thats helps on a side note get urself a nice gorilla pan and a aprialaire hepa filter to keep that indoor coil clean . As for duct sealing i use a combination of gasket tape in places i cannot mastek and i masket all joints and seams . If your attic is unvented think of installing a attic relief fan it will cut down on hi attic temps which cuts down on ur cieling load from ur attic and also cut ur electric comsumption .In my home i get the sun beating my roof from sunrise to about 3 and even though i have a ridge evnt and soofit vents that attic relief fans make a difference . peace and good luck clammy

Abracadabra

I have found that a multitool is best. I've done a lot of cutting out of old lathe/plaster. Least amount of dust, least amount of damage to what you want to leave in place.

I keep the old dull blades to simply cut/score the plaster. Knock the cut plaster away from the lathe. Then switch to a newer sharp toothed blade to cut the lathe. Using a needlenose pliers or something similiar to stabilize the wood lathe while it's being cut helps. Depends how far your cut is from the stud/joist. Sometimes, no matter how careful you are, plaster will just fall apart where you don't want it to. You'll need to cut the plaster back to the studs/joists and patch with the appropriate thickness of drywall.

ChrisJ

Abracadabra said:

I have found that a multitool is best. I've done a lot of cutting out of old lathe/plaster. Least amount of dust, least amount of damage to what you want to leave in place.

I keep the old dull blades to simply cut/score the plaster. Knock the cut plaster away from the lathe. Then switch to a newer sharp toothed blade to cut the lathe. Using a needlenose pliers or something similiar to stabilize the wood lathe while it's being cut helps. Depends how far your cut is from the stud/joist. Sometimes, no matter how careful you are, plaster will just fall apart where you don't want it to. You'll need to cut the plaster back to the studs/joists and patch with the appropriate thickness of drywall.

My concern about a multitool is they seem very awkward to control and it seems like it would take forever to do a 14x30 opening. What multitool and blades would you recommend?

Curious, why you don't repair the damaged plaster with plaster rather than drywall? Assuming it's a small area.

Gordy

A multi tool is the lightest, easiest to control, safest, and least messy of all your choices. If you know how to use one.

ChrisJ

Gordy said:

A multi tool is the lightest, easiest to control, safest, and least messy of all your choices. If you know how to use one.

Ok,
Let's hear some brands, models etc.

Though I have a hard time not disagreeing. A circular saw is pretty hard to beat for ease of making straight cuts.

ratio

This one. Works great, and the best thing about it is that it takes the same batteries as all my other tools. I think these are the blades I found that seem to last pretty well on plaster. They certainly will last longer than bimetal blades.

Gordy

Mine is Porter cable.

Variable speed.

They make cordless models now. However cordless wouldn't last for the size holes you have to cut.

What I like about any model is how you can adjust the
Blade positioned accommodate the work position.

Abracadabra

20v max dewalt
I've tried all sorts of blades. The only issue I've had with the dewalt is that the spacing on the teeth holding the blade is different than most other tools and you have to get the dewalt blades. dremel brand blades won't work. the newer tool might come with a universal adapter. mnine didn't.

obviously if the damage is small, patching with plaster or durabond is fine. but on a larger area if the lathe gets damaged i'd go with drywall. I seem to remember you saying something about 30"

Bob Bona_4

I'd use the Dremel multi..it's a cheap tool, it's going to inhale the dust, so it's not too painful to write off. Get a pack or 2 of blades. The kerf is so tiny there's not much dust. You'll have your bud manning the vac from floor level. Use the spent blades on new cuts if you can until sparks.

ChrisJ

Bob Bona said:

I'd use the Dremel multi..it's a cheap tool, it's going to inhale the dust, so it's not too painful to write off. Get a pack or 2 of blades. The kerf is so tiny there's not much dust. You'll have your bud manning the vac from floor level. Use the spent blades on new cuts if you can until sparks.

Oh,
So I shouldn't have the wife "man" the vacuum cleaner and then blame her for any dust she misses?

See, I knew that was bad advise!

VDBLU

I use a cheap multitool with a fine tooth carbide blade to cut plaster. Mark your opening. Score the hard 1/8th inch or so of plaster first. Make sure to cut it with the teeth not the side. Then cut through the remaining brown coat to the lath. Once the perimeter is done remove the plaster from the lath by cutting each key off. Plunge the saw between the laths and run it accross. Once you are down to just the lath cut 90 percent through one side then go to the other and cut all the way across. You can then stabilize the lath with one hand and cut the last little bit free. This is messy and slow but makes a nice precise cut that you won't have to spend time fixing. I run a shop vac with a high quality filter and a drywall bag. I try to keep the nozzle close to where I'm working but it is mainly an air cleaner. Put down plywood or several layers of cardboard if you have finished floors so that the plaster doesn't mar it when it falls.

Gordy

ChrisJ said:

Bob Bona said:

I'd use the Dremel multi..it's a cheap tool, it's going to inhale the dust, so it's not too painful to write off. Get a pack or 2 of blades. The kerf is so tiny there's not much dust. You'll have your bud manning the vac from floor level. Use the spent blades on new cuts if you can until sparks.

Oh,
So I shouldn't have the wife "man" the vacuum cleaner and then blame her for any dust she misses?

See, I knew that was bad advise!

Your wife not eager to help take part in home improvement projects?

ChrisJ

Gordy said:

ChrisJ said:

Bob Bona said:

I'd use the Dremel multi..it's a cheap tool, it's going to inhale the dust, so it's not too painful to write off. Get a pack or 2 of blades. The kerf is so tiny there's not much dust. You'll have your bud manning the vac from floor level. Use the spent blades on new cuts if you can until sparks.

Oh,
So I shouldn't have the wife "man" the vacuum cleaner and then blame her for any dust she misses?

See, I knew that was bad advise!

Your wife not eager to help take part in home improvement projects?

Nope.
Especially when she's 4 months pregnant.

Fred

Bob Bona_4

I was gonna say, in her current state, not a good plan, bub

Gordy

You can pick up a PC corded for less than a franklin. Storage case, and extra blades, and accessories. Pretty easy to find blades. Dremel is a little more money.

You could go all out for a festool for 440.00

Gordy

ChrisJ said:

Gordy said:

ChrisJ said:

Bob Bona said:

I'd use the Dremel multi..it's a cheap tool, it's going to inhale the dust, so it's not too painful to write off. Get a pack or 2 of blades. The kerf is so tiny there's not much dust. You'll have your bud manning the vac from floor level. Use the spent blades on new cuts if you can until sparks.

Oh,
So I shouldn't have the wife "man" the vacuum cleaner and then blame her for any dust she misses?

See, I knew that was bad advise!

Your wife not eager to help take part in home improvement projects?

Nope.
Especially when she's 4 months pregnant.

Ohh pressure is on. Nothing more cranky than a pregnant wife in the middle of summer.......With no AC......

Bob Bona_4

Didn't know PC made a multi. Looks like about the same price as the Dremel. No question a Fien would be the ultimate, but those suckers are heavy! Would be tiring with overhead work.

Gordy

Porter cable Bob.