Options after peeling paint on new plaster

[IanM18]

Morning,

Had walls plastered (skim coat), and in two places only, the mist coat, and top coat all peeled off.

Really don’t know why, used the usual mist coat ratios of paint to water.

Anyway, I have scraped all the peeling areas back, sanded down the edges so it’s all smooth and blended, and then peel stopped the whole area (belt and braces!) and then did a new mist coat, then some base coat, then two top coats.

But….

Looks fine in “indirect”light, but this morning could see the lines where the paint peeled away, feels smooth to the touch.

Wondering if I just get another re skim, or if I keep layering up the paint, it will eventually start to become un noticeable?

I’m not looking for perfection, just so it’s not really noticeable.

Photos attached so you can see what I’m talking about.

Any thoughts tips or advice??

 

[Wayners]

Sand
Thin skim. Can use a box of toupret filler.
Need a flat block to sand. Preferably with electric hooked to vac.
Mist coat and paint.
Look's like your rolling and going back over too much. The drying paint Is picking up cause the rough surface and could contribute to the paint flaking as you are pulling off as its setting.

12 or 15inch roller and don't mess with it. Just cut in first and roll wall not going back over yourself.

 

[IanM18]

Thank you, will give that a try.

On the painting thing, is that what gives that slightly textured look? I use a short Hamilton perfection roller, get a stippling like that no matter what I do, Dulux paint, but it feels very thick as it goes on.

Am I getting that wrong as well?

 

[Wayners]

Dulux with the dog on has thixotropic agent in.
Trade paint has no thixotropic agent.
thixotropic can make paint too thick although none drip for DIY market.

If paint is too thick add water. Needs to easily flow out roller and some people end up with a solid hard roller as they don't keep it loaded.

Mist coat or sealer helps slow down suction when emulsion is applied so paint levels.

Try a medium pile. I suspect you are rolling like mad in all directions and not getting very far. Roller becomes hard and is not loading with paint.

I do the wall it in strips. Last roll top to bottom only.
Then next band and finish with last roll top to bottom.
Roller nap going in same direction keeping a wet edge as you move along wall.

 

[opps]

Really don’t know why, used the usual mist coat ratios of paint to water.

Which ratio was that though? There is some really bad advice on the web. Some people, often plasterers, recommend over thinning the paint. Paint is thinned over new plaster to deal with the "suction".

The rationale behind it is that paint applied "full" fat will see most of the water sucked into the plaster. Water based paints cure through a process whereby the water evaporates off and the molecules bond down to create a film as the water evaporates off. If the plaster is too porous, the water is sucked into the plaster too quickly.

When rolling paint, the roller simultaneously tries to apply paint and pull it off. It can only pull the paint off if the base coat was not thinned properly.

My advice is to ignore anyone other than the manufacturer of the paint. If they say add 10% water, take their advice. They have no incentive to lie.

If you, for example, thin it by 30%, you have wasted your time. You still haven't dealt with the suction. All you have done is paint "water" over the wall.