I'm no expert on home reno, but I would think a rotozip or similar tool would be better for this then a router.

 

HI Trevor

Your router will do the job with a bit that's called a panel bit..

http://woodworkersworld.net/panel_bits.shtml

It's Made to plunge in and run on a 2 x 4 in the wall,,to cut out a window opening or door opening quick and easy, it will cut the plaster and the lath boards that support the plaster at the same time...but you will have a mess all over the floor, so put a tarp/plastic down b/4 you start if you have a vac.pickup on your router use it..help keep the dust down..

If it's in a office the wires should be in pipe but you want to kill the power and double check the wall b/4 you start..water lines should not be in place behind the wall the norm..
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Trevor,

A hammer and chisel should do the trick. You don't know if wires or pipes are behind the plaster. Use the chisel to score straight edges. Plaster is tougher than sheetrock and a dustier. Suggest masks and seal off exit yo contain dust.

 

hello Trevor,

you might want to check before using the router and make sure there is no metal lathe behind the plaster first, that would be tough on a bit imho.

 

those are all great ideas
I think I am going to stick with the hammer and chisel though-it is no fun to do extra repairs just for a cabinet-i.e. pipe/wires

 

It's not like you have to set the bit 1 1/2" out the bottom of the router.
All you need is 1/2" or so and you don't cut wires or pipes.

 

I'm with Mike on this one, four pieces of 2" x 1" pinned or stuck with double sided carpet tape spaced the diameter of the router base from the opening size, for example if the opening is to be 2' square and the router base dia. is 6", then the inside of the square formed by the 2" x 1" 's will measure 2' 5.5" square. Then set the router to the thickness of the plaster, I would use a standard low cost 1/2" straight cutter that could then be binned at the conclusion.

Size of opening is arrived at: dia. of base - dia of cutter + finished size of opening, therefore : 6" - 1/2" + 24" = 29.5" or 2'5.5"

 

The amount of debris and dust kicked up by a router would be tremendous.

The type of plaster would depend on the age of the building. Pretty much anything built since the 70s is blue board and or MR board as a base, (no lath or chicken wire).
Anything 40 to 60s would likely have 3/8" lath possibly with animal hair mix. Older and or larger buildings and or balloon framed structures might have chicken wire behind the lath.

I'd suggest marking off the area you want to open up, scan the area for electricals and metal and then use a reciprocating saw. It'll produce the least amount of dust and debris over the time used cutting the RO with the fastset cutting time.

 

I have to disagree with the recip saw comment. This house is not consistent from room to room. In one room is it lathe and plaster-the next 1/4 sheet rock with a skim coat of plaster on it. I have used my Sawzall with a plaster cutting blade and a carbide blade and they get tore up pretty quick. At $15/blade it is getting expensive. The real reason that I asked this question was for 2 reasons.
1-to see how versitile a router can really be?
2-to see if purchasing a Rotozip was worth it? I have read on several posts about the need for a larger router and small laminate trimmer. Well correct me if I am wrong, but I do not see the difference between a laminite trimmer and a Rotozip. Rotozips are made by Bosch and when you hold one up next to the Bosch Colt the function-amps-speed are nearly the same.
Plus with all of the attachments for a Rotozip, I think it could be a handy little tool to have around. They have the capability of a 1/4" collet-so using a laminite trimmer bit in it is possible, plus looking at one I would think it is pretty easy to make a larger subbase for it which would make it ideal for laminite trimming. What do the experts out there say? Is this project screeming "Go buy a Rotozip"?

As always-thank you for the advice!

 

Hi jeep

A Rotozip is just a router,,take a hard look at the bits,,that like to snap off very easy...the Rotozip just didn't get real food when it was going up..

You hit one nail /screw and the bit is gone..dry wall not a big deal the norm but anything else well ...

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Jeep Man,

It doesn't matter what the material is the sawzall is the best tool for the job.
Your error was in choosing the wrong blade for the job at hand and spending too much on it at that.

You should have purchased a "Fire and Rescue" or "Demolition" blade. I use them all the time in remodeling, cutting out ROs for windows, AC and doors and for demolition. I refuse to buy new blades for every job I go to even though the customer pays for it.

I do this kind of thing for a living, both those blades are made for going through metal, wood plastic you name it. , I have 3 customers in the historic registry, One from 1787, (now a day care center) and an Inn from 1860 something. One of the 1st 15 or 20 houses built in Woods Hole with a tower overlooking the sound that was used as a lookout during the Civil war.

All 3 buildings have plaster lath with chicken wire backers. I discovered the Inn was plumbed for gas lighting in a remodeling phase a few years ago. The F&R blade is cutting through the plaster, nails and very old fir and then I hit something hard, I stopped and sledge hammered material away to find out what was so hard and found an old gas light pipe nearly cut through to the ID. I stopped called the Company that does all the plumbing at the Inn, was told It's been capped off for over 60 years cut it out and I did.

I've made over cuts into concrete without any serious damage to a blade. I've demolished entire cottages with one blade.

 

RotoZip

My RotoZip is the one tool that I would never hesitate to loan out. Even to a complete stanger in a prison jump suit, driving a stolen car.

I think I've purchased every possible accessory and I can't say that I have found a good use for the thing. Needless to say, it's always for sale, at a really low price.

TTG

 

ok so i have used the hammer and chisel to cut out my openings. I have one final question regarding this renovation project?
We need to trim off a 1/8 inch off of a hollow core door. Does a router make a nice clean cut without chipping using a straight cut bit and a guide? Or should I use my circular saw with a plywood blade and mask the end with tape? I have done the latter for as long as I can remember-it works OK-but I am trying to figure our the full potential of my router.

 

HI Jeep

I would stick with the power hand saw but I would recommend a 1/16" wide 6 1/2" blade, carb. tooth..you just never know what you will run into on the door... the masking tape will help with the rip out but a new blade is the real key I think...once it's cut that's it...rip outs are very hard to fix as I'm sure you know...


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Hi Jeepman,

Make sure to "score" the wood on the door first. A utility knife works. This will help lesson the chance of splintering the door. Bj is right about the "tape" method. I suggest using painters tape. Easier to remove.

Hope this helps.

 

Hello Trevor! I have a roto zip. And they are very handy if you are doing a lot of plaster, or small type projects. They are also handy if you are putting up siding. After i was done with the plaster, and siding, i have not used it a lot. It is lighter than a bigger router, and that makes it easier to work with. The angle head is used for cutting metal, and grinding metal, cement, or anything you have in a tighter place. That is also a neat outfit. I bought mine when it was a family venture and thats quite a while ago.

 

To remove 1/8" from the bottom of a door I would use the circular saw, but for the sides the router against a straight edge. Scoring and/or masking tape is also the way to go if the door is covered with plywood but not necessary if MDF.

 

Rotozips are great for drywall work, and very useful with suspended ceiling tiles. With the proper bit they cut wood easily if not quickly. With the carbide bits they cut ceramic tile. They are useful tools but unless you do one of the jobs mentioned for a living they will most likely sit in your pile of unused tools.

Working with plaster is a whole different animal. You never know what you will find behind it. I agree on the demolition blades/reciprocating saw method. If you are itching to spend money on a new tool that you can get your use out of consider a Porter Cable Tiger Claw saw. This tool is highly versatile since the knuckle lets you get into very tight places. If you want a Milwaukee "Sawzall" be sure to spend the money for one of the high amperage models like the "Super Sawzall". The difference is tremendous.

 

Hi guys

The only time I dig my saws all "Sawzall"out is when I don't care what it looks like when I done, "Demolition" is the key word for me,, I don't anyone that cut a strait line with one or to say a clean cut line.. most of the time it looks like it was done with a chain saw..

But I will say I do pop in a metal cutting blade now and then and use it to cut old ex pipe out from under the car/truck and put the old pipe in the trash can ( "Demolition saw: )

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Rotozip does one thing well - cut out for electrical outlets in dry wall.

Thats it ! Try knocking a access hole with your hammer in the wall so you can look into the cavity. Then go with either a router, or sawzall. Seal the work space with plastic from floor to ceiling and wall to wall - or you will have dust everywhere to clean up.

You can use the sawzall to rough open the hole and the router to flush trim to a joist.

Wear a good dust mask.

 

Bobj3,
The recip saw like any tool requires practice to master.
Who's the guy that thought of using a chainsaw for sculpture?

No question the recip saw is a muscle tool, but it takes finesse to use it. If one is afraid of a tool and can't overcome it they shouldn't use it. I saw it all the time in the building trade, afraid of airguns, saws, heights.

As the rational goes, right tool for the right job, same thing for the accessory, (read blade). Short, long, thin, thick, hardening, tooth count and angle, each aspect has an excel point.

Add all that up and you still produce kindling if you don't know the tool, its limitations and how to take advantage of it.

 

HI Ron

I'm not afraid of the saw but it's just one step above the chain saw for me ,I know many use it on the job sites,but for ruff const.I think,I have seen guys hanging off the ladder with the saw in one hand and one hand on the ladder or hanging over the side of a roof cutting boards off..or to cut a window/door hole out, it's a very quick way to do things but

I just love to see the plumbers use it , to cut out a notch out for the pipes out of the floor joist that's a no no as you know the right tool for the right job " Demolition saw "


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Bobj3,
A huge portion in the term "fear" is uncertainty.
Good framers are bold by nature. If you can't move around like a monkey after a couple of months you won't last. Most employers don't care how smart you are, (at 1st) you can teach pretty much anyone but if you can't hang, (read) move quickly, carry at least 10 studs at a time, up and down ladders, over bare joists walls and roofs with -0- acrophobia then you're useless.

A very true and embarrassing story,
A bunch of yrs back, late spring mid 80s (still lean and mean, mostly mean) framing condos in New Sea bury I was squeezing myself up through 2 rafters at the ridge to nail the final piece in. Both rafters caught my pouch's belt as I wiggled and shimmied up pulling my pouch and cut offs off past my ankles down to the ceiling joists. I began cussing quite loudly as I realized I was going to be pouch-less and pant-less on the roof.

There are some things guys and possibly nuns will ever let you live down. It just so happens that there was some kind of thing going on, (over 100 guys all ages in a close area and somebody got the idea to send a bunch of visiting nun nurses to the job site to do BP tests on as many guys that would sit for it. Lucky for me they set their station up close enough to hear and see the underwear clown.

All the plumbers I've worked around were butchers when it came to cutting. The worst of them didn't tell you what they hacked and then when final inspections roll around it would fail because the plumber didn't bother to mention the couple of joists
left hanging.
There are rules for notching and cutting holes in joists and they differ as the distance from bearing increases.

 

Just saw this post and my comment re the OP is there probably isn't anything worse for a router bit or it's bearings than plaster dust.

Plaster dust almost killed my Bosch in-line jig-saw, but the wonderful doctors at the tool fixer brought him back to life.

Plaster is concrete!

Use a Rotozip. If I have a lot of cutting to do, I use an angle grinder to cut thru the plaster, then I use a sawzall to cut the lath.

Good luck!

 

I have a rotozip too the 2nd one to date same problem, gypsum dust killed the 1st one. I only use it when I'm doing tile work now.

There are a number of carbide rasp bits that work well for smoothing tile cuts down so that a grind block can finish it off.

I lost a PC 694 vk to composite decking.