Mist coat and Diamond Woes....

[tacopowell]

Had one of bedrooms plastered a couple of weeks ago,
All dried out, I mixed up a mist coat comprising of roughly 9 parts Leylands Contract Matt PBW and 1 part water,
Mixed well.
covered and dried well,
I decided to start the first coat of Dulux Diamond PBW, I put this on a diluted 9-1 ration as well as its already a very thick coat and the Leyland is by nature a very chalky finish and I wanted it to adhere, Went on well,
However when I did the masking tape test this morning, It's pulled patches of the Diamond off, Not lots but certainly enough to make me concerned,
Questions are;

Should I not dilute the Diamond? should I do another coat of leyland mist on the walls before starting diamond?

Its going to be a nursery, hence the diamond paint so durability really is a must....

Any help would be appreciated!

 

[footprints]

You did the right thing in using a paint for new plaster, but over-coating with a "normal" paint will cancel out the breath-ability of the new plaster paint causing problems as you see.
Normally you do all the coats in "contract" or "paint for new plaster" he wall can then dry out fully. Two weeks is no where near enough, you are looking a months for total drying, so you use breathable paint and when next it is decorated perhaps years later any paint will do.
Not much you can do really just touch up and see how it goes, you may get away with it or you may get flaking later.
Sorry to be the bearer of bad tidings but can't suggest any solution other than stripping the wall and no way do you want to get into that, just as I said see how it goes and touch up as required

 

[tacopowell]

Dulux Diamond is a water based paint, Therefor suggesting its also a breathable paint,
The skim had gone pink already, seemed well dry.
The Leyland is really chalky which makes me think I hadn't watered it down enough,
I've since given the walls a sand down, Which has helped anyway as there was plenty of imperfections on the skim,
I've given it a quick wipe down with a very slightly damp sponge, I'll give it another coat of mist this time at 60/40 Contract/Water.

 

[footprints]

Dulux Supermatt is their paint for new plaster.

 

[Robbie uk]

If your using masking tape, it will need to be a decent low tack one like Frog tape, or Rhino Tape. One mist coat is all that is needed. Contract matt doesn't have any vinyl in it so will feel a little chalky. A vinyl matt or Soft sheen emulsion may not be breathable due to the PVA in it, hence why a mist coat is required with a contract matt first.