Removing paint from a plaster wall: what sander, abrasive, and dust extractor?

[BrianHammerstein]

Dear Fellow FOG members,

I do not own any Festool products at present. I need to remove several layers of oil and water based paint from a wall down to the plaster. I have had the paint tested for hazardous levels of lead, and it does not have any.

What sander, abrasive, and dust extractor do you recommend? I intend to prime and paint the plaster once bare.

 

[Eli]

Any mechanical means you use to take a bunch of layers off will most likely gouge the plaster so be ready to skim coat if you go that route. I'd wash the walls down with a chemical cleaner (they have one called ESP here in AU), and paint over it. Especially if there's no lead in it. If you just want an excuse to buy some Festool gear for the job, use a Rotex and a vac. 24 or 36 Rubin.

Often with really old plaster with many layers of paint you can get the whole wall clean just by getting a putty knife or drywall knife under and slicing it off the wall in big layers/sheets. Depending on the amount of lime in the plaster you may have to prep before you paint to make the alkaline (?) surface more base, or you won't get a good bond w/ the primer.

I say if paint is sticking to it now just go with it.

 

[bruegf]

I used my Rotex to remove cracked and peeling paint on my bathroom ceiling.  For me, the Brilliant paper worked much better/quicker than Rubin.  Seem to not clog up anywhere near as quickly.

Fred

 

[Dan Clark]

Brian,

I believe Fred is correct about the paper to use for paint removal.  This is the Festool abrasives catalog:http://www.festoolusa.com/Web_files/Abrasives_brochure.pdf.  Festool makes several different types of abrasives.  Unlike most catalogs, this one goes into a lot of detail about which abrasive to use for which purpose.  And it provides details on how each abrasive is made.  The catalog recommends Brilliant 2 for this purpose. 

I've not done much of this and have not used my Festool sander for removing paint.  However, I've had to deal with some difficult surfaces a few times.  If it was me, I think I'd do the following:

1) Lightly use a scraper to remove the flaking paint. 

2) Try Brilliant 2 in one or more grits to remove the looser paint and maybe all of the paint.  You may want to try Vlies also.  I have it, but have not used it yet.  It's interesting stuff; more like a scrubbie than sandpaper. 

3)  Repair any gouges.  My experience matches Eli's.  When I removed wallpaper from a bathroom, I had to repair lots of gouges.  (Of course, it might be that I'm just clumsy.)

4) Primer the walls.  I'm not sure about plaster, but I've used a Kilz - a stain-killing primer - ensuring that there's no bleed-through.  It might be good for this purpose also.  Follow that with 1-2 coats of a good quality primer.

5) Paint.

Regards,

Dan.

 

[bruegf]

Did you use your Rotex in Random Orbital or Rotex mode?

It's been a while, so I'm not positive anymore, but if I remember correctly I used orbital mode for the the heavy grinding, but random orbit for the rest.

Fred

 

[ericbuggeln]

Brian,  i do alot of wallpaper removal here in ct (usa) and have been in the paint business for about ten years.  Not a lot of plaster work, but I have begun to use the Rotex 150, ct 22 vac, and whatever already used before sandpaper I have laying around.  This is a great way to re-use old sandpaper.  My experiences are with Brilliant and Rubin, but have always used a grit that won't gouge, on low suction setting and fine sanding setting. 
It sounds to me like you have a "trainwreck" situation which could be handled many different ways.  The above info is all good, but you have to ask yourself how long do you want to work on this before you get to a surface that is exceptable to you for finishing coats.  Some of those methods will be really messy and time consuming.  Through many jobs where my guys were removing wallpaper and I was in the next room with my festool toys I realized that even though its not a planex, it has a lot of the same capabilities and is much faster and cleaner then doing by hand.  The only thing I am wondering is why festool made a completely different vac system for the planex?  Drywall dust must not be good for ct series vacs I would assume, but haven't seen any evidence.  I also wonder if there is a better bag / filter combo for this procedure that would wear less on the unit?
As far as I know Porter cable is the only manufacturer that has a drywall sander that looks much like the planex.  You can rent it for $60.00 a day at my paint store.  The one major advantage is that the Porter cable is on a pole  and is about a 12" diameter pad I believe.  The Rotex 150 will make you sweat for a whole rooms worth of sanding.  These are all things you may want to consider.
If I were you, i would use a 6 inch drywall knife and scrape all loose paint off.  Then use 100 - 120 Brilliant, or a used up 50 or 80 can do the job.  Make sure that there are only low spots from peeling or gouges, but no spots that are raised up.  To make it more clear, the next step is to use Zinnssers Bullseye 1-2-3 primer.  This is a stain killer, primer, sealer that has a "semi-gloss like finish" as opposed to most that are flat.  Once you have all walls primed white, then you can shine a worklight on the wall and systematically fill in all the low spots or valleys with joint compound.  It's like a crime scene investigation and will show you exactly where you are low and need to fill in.  If there are a lot of large valleys, then I mix compound til the point where I can skim coat the wall.  Either way the Bullseye 1-2-3 is the backdrop to a superior finish, especially when sanded over with random orbital.  The sealer component is what will save you time, because you will be sealing all wall surfaces as opposed to just priming over them.  If you prime only, then anything underneath that wants to move will take it with them.  The sealer will give you a new surface to begin working on that you won't have to worry about all of the past "trainwrecks" underneath anymore. This primer will show scratches if the grit is too low, even with hand sanding so it is the perfect compliment to the festool set up's random orbital motion.  It is still scratching, but to the point where you can't see or feel it.  You can get a "plaster like" finish on drywall if you will.
Once you have smoothed your repaired valleys into the existing surface you can re-roll entire wall with primer.  I usually quickly sand over primer with 220 brilliant and top with two coats of Benjamin Moore.  In your case stay away from semi-gloss because it will magnify any imperfections you missed.  I would recommend Eggshell Aquavelvet, which still gives you "scrubbability", which is semi's most desirable characteristic in two weeks.  If you are really worried use Zinssers Guardzz product which is strictly a sealer and goes on like water, so you roll from baseboard up otherwise it will be everywhere.  Must ventilate and where respirator, but you would know that the second you opened it.

 

[Dan Uhlir]

  it's hard, for me, to comment without actually being there, however, I would agree with Eli that if the paints sticking now just go with that. Peeling off the paint will be more than twice the work plus it's likely to mess up the plaster.
  Personally I would scuff sand the existing paint with some 100 grit brilliant if that's to gritty go down to 120 you can figure that out, then was the wall with t.s.p.. Then I would go to a high quality paint local paint retailer i.e. benjamin moore, pratt lambert type dealer and see what he recommends, for primer. You may be pleasantly suprised that a good quality latex primer will work again much easier. I would apply at least 2 coats of primer tinted similar to the color you choos to topcoat with especially if your using red, actually with reds I'll use a grey primer,. I would also conmsider the color of top coat, reds and yellows can be difficult too much colorant. How bout a nice blue or tan. Again 2 coats of primer usually when I apply primer it looks like it's been painted and then and only then do I topcoat.Good quality primer something with a little elasticity, not somehting that's gonna dry and crack, and you all know who I'm talking about.
    As for sander mode whatever it take's usually a little of both modes.
    Painting is actually kinda fun, season's changing looking forward to getting some painting done, better fire up the sprayers. Yee hah
                                                            Thanks
                                                                Dan

 

[Eli]

TSP! That's the stuff I was trying to remember. They actually call it ESP here, and it's different stuff. (not extra sensory perception you smartarses)

 

[JJ Wavra]

Hello,

Just kind of a random thought but when I moved into the current house there was quite a bit of old latex paint on the floor.  I simply put a damp cloth in the microwave for a few seconds and held it on the paint until it softend and reactivated the latex.  I wonder if you could do this on the wall.  the old oil paint should form a barrier between the plaster.  If you could soften the latex on top then maybe you could scrape it off with a taping knife.

I have never tried it on a wall and this is totally out of left field.  Who knows.

best of luck on the project,
JJ

 

[Steveo48]

TSP is trisodium phosphate, easily found in hardware stores (around here anyway).

A few points to ruminate on.....

Is your problem the red enamel paint?  Could you just sand down to it and use "Liquid Sandpaper"? ( a trade mark name for a chemical mix that will etch the enamel and allow other paint to stick to it).  I used it on sky blue gloss enamel and it works really well.  You'll need a lot of ventilation.

Ask yourself if you really want to spend $440.00 on a sander, plus the vac to do this.  I'd also go with some sort of negative air pressure in the room to get as much of the dust out as you can.  I use an old furnace squirrel cage blower, but a box fan will work really well too.  Shop vac also makes HEPA canister filters and vac bags designed for very fine dust.  I use this setup with my Festool sander at home.

You'll need real respiratory protection, not a 3M 2 rubber band dust mask.

The plaster may also include asbestos in it. 

Steve

 

[wiser_guy]

i did what Brian wants to do (remove several layers of oil and water based paint from a wall down to plaster) last year in an 60's apartment and what a job that was! I went down this path after realizing that the existing coat i was presented with, was not adhering well to the plaster underneath it and would strip off relatively easily with a putty knife. And, let me tell you, was i glad i did it! All previous coats and grades of paint over the years came off and i was presented with bear clean, plaster walls which after i sanded down with a palm sander, spackled, re-sanded, towled down, primed, re-spackled, re-sanded, re-primed, then painted three coats.

Now, a year later, i m presented with the same dilemma for another 60's apartment. Strip walls down to bear plaster or skim coat over existing coats of paint. Judging by my previous experience and provided that several coats of paint have accumulated over the years that strip off relatively easily, i gear towards striping down to bear plaster once more. It's a time consuming job but the finished result puts a smile on your face. The apartment looks new and its value is increased times over if you are going to sell or rent it. This time i look for ways (other than chemical or heat-gun ones, which do not work) to make the whole process easier.

This time around I 'm considering Telescopic Power Grinders. Yet, i 'm very doubtful about their applicability. Does anyone have experience on using Telescopic Power Grinders for the purpose of removing old paint from plaster walls? So, far the best way i can think of, based on my experience, is using the good old putty knife provided the paint is not sticking, otherwise, leave it alone and skim paint. The problem arises when one wall strips off easily while a section on the next wall is sticking like crazy and you very much want to remove it as well. Or you dont? xaxa