Rubbing down newly plastered walls?

[Bosso]

Hey guys,

Had all the walls and ceilings in my home skimmed a few weeks back and it's now time to paint My question is this, I have been given lots of different views on how to rub the walls down and I need some expert advice. The plasterer, to me, did a great job but I have some trowel marks and small bumps, nothing serious, but enough to stand out.

Do I use sandpaper on them and if so what grade and if not, what?

Any help would be appreciated.

Thanks

 

[Richard C]

You should never need to rub the walls down before painting, any half decent plasterer will always leave a finish ready to paint. If it's the odd imperfection then OK but sannding the whole wall is a last resort for a botched job! Trowel marks, by their nature, are indentations in the surface & you would do better to lightly fill these & rub them back to the surrounding area, not try to sand the whole area back to loose them. With the lumps & bumps, you may have no real choice but to sand them back but sanding the plaster surface too much will give patchiness in the paint finish, requiring additional paint coats to cover it up.

Personally, I don’t like sandpaper & always use wet or dry for rubbing down; for smoothing filler I use 120 grit.

 

[joe-90]

I think he means trowel lines which are raised. They shouldn't be there at all but if they are I'd use an angle headed scraper with a razor sharp blade to run over the surface (B&Q about a fiver). Then touch up with polyfilla. Avoid sanding the plaster where you can.

 

[Bosso]

Thanks guys I will try your suggestions and update you to let ya know how I get on!

 

[Zampa]

Never rub down bare plaster you'll rip it to shreads..nd the scratches will show through.

Mist coat it first then its ok to fill and rub down...because filler is a bit harder than plaster if you fill it first then rub it down you'll scratch a ring mark around it.

 

[Bosso]

Thanks Zampa,

What exactly is mist coating? Sorry to sound like a novice....but I am

 

[Zampa]

The 'mist' coat is a thinned coat of either contract or vinyl matt (depending on the plaster surface) emulsion.

Its the first coat you put on...people mistaken think its a sealer, it isnt, if anything it 'primes' the walls ready for the next coats..it enables you to see imperfections on the surface and deal with them.

Called 'mist' coat because it resembles mist.

Painting new plaster probably makes up 20% of most queries on here so your not alone mate.

 

[Bosso]

Thanks Zampa

I start later today so will update you on my progress.

Just one other question, when I put this mist coat on and spot the imperfections I know to fill them with polyfila but what would you use to rub them down? If sandpaper what grade?

 

[D.S.D]

Hi Bosso,

might be doing polyfila an injustice here but unless its changed (goes off like iron) I would use tetrion, easi fill or toupret. All are interior powder fillers and are a dream to rub down. My prefered choice would be the toupret. i have just started using that and it is good I use 120 on these fillers as they are soft and rub down a treat. If you are heavy handed use a 180 or higer. dont rub to hard let it do the work for you and go careful with the plaster walls as Zampa said. Good luck