Power sanding old painted plaster walls?

[will sanders]

I am going to be sanding down most of the walls in my house in preparation for painting and some wall paper. The issue I have is the walls are in bad shape with MANY very poor patches, I have a Dewalt RO sander, will this work well enough with a shop vac to keep the dust at a minimum? Or should I invest in something better? I thought maybe a Festool but I have bought cars for less!

[Jerry Booher]

Even with nobody in the house and no heat or cooling fans, the dust will still go from one end of the house to the other. All except the dust that goes up your nose and in your eyes. Not very healthy. Use a good dust mask.

I used a Loveless drywall vac with its triple filtration to clean up after trying a Craftsman and a Ridgid. Drywall dust (Plaster of Paris) goes right through all but the Loveless.

IMO the RO sander will produce way too much dust and give a very wavy wall. I used a long sanding board to even out the waves. Sand it at a 45 degree angle from both directions.

Jerry

[Steve Schoene]

Take care here. If these walls were painted before 1978 there is a good chance that they have lead in the paint. If before WWII then lead is almost a certainty.

When walls are in bad shape, but more or less sound, then often the easier solution is to apply and tape a thin sheet rock. This is where the 3/8" board can come into play.

[Phil Green]

Will,

I agree with Jerry. I did a couple of jobs early in my career with a RO sander. I learned how to make the RO sander work, but really only as a first pass sander, getting all the lumps and bumps out of your first coat. Do the rest by hand with open grit sand paper and one of those small sanding boards attached to a broom handle. I recommend to use a long board if you have to on a wavy wall.

Since I rarely do this kind of work, it never made sense to invest in all the proper sanding equipment to minimze dust. I do use a very good quality dust mask to filter my air and goggles to keep the dust out of my eyes. You end up looking like a snowman, but there is not much you can do about it.

Phil

[Jon Knauft]

Will,

I was in a similar situation when I remodeld my first home. It was a 100 year old farm house with plaster walls throughout. Menards has a shop-vac attachment that you can use with drywall sanding sheets. They also have a system that runs it through a bucket of water to take out the fine dust. I used the first option with Fine drywall sanding sheets along with a drywall filter bag and hepa filter in my shop-vac and came out nearly dust free. I still used a dust mask though. There were at least 10 layers of paint and since the top layer tested positive for lead I'm assuming they all contained lead.

If I remember correctly the sanding attachment was under $15.

-Jon

[Neal Clayton]

I am going to be sanding down most of the walls in my house in preparation for painting and some wall paper. The issue I have is the walls are in bad shape with MANY very poor patches, I have a Dewalt RO sander, will this work well enough with a shop vac to keep the dust at a minimum? Or should I invest in something better? I thought maybe a Festool but I have bought cars for less!

a) the plaster will probably be too hard, you'll just make a mess and not fix anything. plaster isn't drywall mud, it's not typically sandable
b) as others mentioned, the lead issue
c) lime plaster dust is very fine, fine enough to pass through most air filters, it will dust your entire house via your HVAC units

how bad a shape are we talking about?

unless you have extensive water damage, most repair to plaster is pretty simple.

if you do have extensive water damage, that's another matter.

pics would help.

either way: short answer is you can't fix a plaster wall by sanding on it.

[John Schreiber]

I had a similar situation and after attempting to sand, I realized that wasn't going to work. I ended up skimcoating the entire room and putting up wallpaper with a strong pattern it it.

Not a great solution, but good enough.

[Jason White]

You can use the ROS with a shop vac for sweetening the bad patches. Sand them flat, skim coat with mud (using fiberglass mesh tape if you have hairline cracks) and feather the edges of the patch. It'll take 2 or 3 coats of mud to get them perfect. You'll still get some dust, but it'll be better than doing it without a vacuum.

For larger areas, however, you're better off just using a pole sander and some 100-150 grit paper. Avoid the sanding "screens" unless you're only sanding joint compound. They leave a lot of undesirable marks on larger plastered/painted areas. I tried them a few days ago on some painted walls and they did not work well at all. Lots of visible lines on the walls.

Jason

I am going to be sanding down most of the walls in my house in preparation for painting and some wall paper. The issue I have is the walls are in bad shape with MANY very poor patches, I have a Dewalt RO sander, will this work well enough with a shop vac to keep the dust at a minimum? Or should I invest in something better? I thought maybe a Festool but I have bought cars for less!