Sanding before decorating - how far do you need to go?

ashe

Our paint is crap on our walls - when I did our bedroom I gave it a good go with orbital sander and dust extraction to a shop vac but I feel I went too far as tried to get a smooth surface all over. I've got a lot more rooms to do so bought an evolution drywall sander which takes 225mm discs. I've given it a go on our hallway and although its getting a lot off, I can still see there are parts where the paint is lower than the smooth surface but feels like getting to that point will take forever - I've tried 60, 80 & 120 grit discs. 

Is it a case of the paint will just fill those parts in, or do I need to persevere?


 will add a photo. 

ashe

Current colour was beige but you can see it was deep red previously. I presumed with a large grit paper it would take off the beige and quickly get down to either the red or the bare plaster even but it is fairly slow going!

the surface still has a strong orange peel feel to it which I was hoping to sand away. Is it easier to scrape some easyfill over the bumps with a trowel and then sand smooth & mist coat? Or am I going too far?

mi-key

Beware if you start getting to the point where you are taking plaster off, you will probably end up with the wall being very uneven and when repainted you will see dips in it as the light shows makes it look even worse.

There is stuff like polycell smoothover which can be quite good on uneven paint surfaces

ashe

mi-key said:

Beware if you start getting to the point where you are taking plaster off, you will probably end up with the wall being very uneven and when repainted you will see dips in it as the light shows makes it look even worse.

There is stuff like polycell smoothover which can be quite good on uneven paint surfaces

I'm pretty comfortable filling walls and have done quite a lot of large holes, the problem is in the opposite direction but don't really want to paint my entire house with Polycell, surely decorators don't do that? Surely easyfill would be better for it and less expensive? That polycell stuff is £22 for 2.5L and says covers 5 square meters, feel like it's a lot compared to easyfill which at this minute depth would go a long way?

mi-key

ashe said:

mi-key said:

Beware if you start getting to the point where you are taking plaster off, you will probably end up with the wall being very uneven and when repainted you will see dips in it as the light shows makes it look even worse.

There is stuff like polycell smoothover which can be quite good on uneven paint surfaces

I'm pretty comfortable filling walls and have done quite a lot of large holes, the problem is in the opposite direction but don't really want to paint my entire house with Polycell, surely decorators don't do that? Surely easyfill would be better for it and less expensive? That polycell stuff is £22 for 2.5L and says covers 5 square meters, feel like it's a lot compared to easyfill which at this minute depth would go a long way?

If you are experienced in filling then easyfill should be fine to smooth them out. 

ThisIsWeird

The first thing that will make a world of difference is using flat matt paint instead of the silk that seems to have been used with the beige.

I'd personally paint a test area at this stage, and that will instantly (well, when it dries...) tell you if more work is required. The section in your photos appear to have a light source at the far end, and a low viewing angle, both which will quickly highlight any obvious remaining flaws. You never know - you may have done enough

GDB2222

Fortunately, I don’t have such high standards for decorating, so what you have there would be fine for me, and I would just slap some Matt emulsion on. 

Out of interest, why not stick lining paper up? Won’t that give you an excellent finish, plus it’s a lot less work than sanding forever? 

FreeBear

ashe said: the surface still has a strong orange peel feel to it which I was hoping to sand away. Is it easier to scrape some easyfill over the bumps with a trowel and then sand smooth & mist coat? Or am I going too far?

I've been using Knaul Fill & Finish to patch up some walls here. Once dry, going over with a moist sponge float helps to feather in the edges and take out any small humps & hollows - A lot less mess than sanding.

Wickes do a 5Kg tub for around £17, but if you shop around, a 20Kg tub shouldn't cost much more than £30.

ashe

GDB2222 said:

Fortunately, I don’t have such high standards for decorating, so what you have there would be fine for me, and I would just slap some Matt emulsion on. 

Out of interest, why not stick lining paper up? Won’t that give you an excellent finish, plus it’s a lot less work than sanding forever? 

I hate lining paper, and we have cats so they would probably just rip it off. Plus when you scratch a wall you can just quickly roll over it or fill and roll vs having to rehang a sheet of paper. 

ThisIsWeird

You have probably done enough work, Ashe. One way to find out...

ashe

FreeBear said:

ashe said: the surface still has a strong orange peel feel to it which I was hoping to sand away. Is it easier to scrape some easyfill over the bumps with a trowel and then sand smooth & mist coat? Or am I going too far?

I've been using Knaul Fill & Finish to patch up some walls here. Once dry, going over with a moist sponge float helps to feather in the edges and take out any small humps & hollows - A lot less mess than sanding.

Wickes do a 5Kg tub for around £17, but if you shop around, a 20Kg tub shouldn't cost much more than £30.

I've ordered a tub of this so will see how I get on!

ThisIsWeird said:

You have probably done enough work, Ashe. One way to find out...

Here is hoping! We had some minor bubbles in our bedroom, but weirdly only at the top of the walls and they weren't huge or noticeable but thin you would see them if it happened here so trying to do everything possible. We have a small part in the hall where the radiator is that we need to paint so the plumber can come and rehang the radiator (you can see between the fins so needed doing), so we'll give that a go this week and see how the paint takes to it. 

one other query - is it a specific kind of paint that is causing this to happen, or sanding too fast? Pads don't cost the earth but it is happening quite quickly and usually I'd get a lot of life out of a pad on my orbital but it's like it's melting the paint and then it's a hugger to pick it all off