Mist coat ratio

[harlow]

When doing a mist coat why do people recommend 50/50 if the tin says 9 parts paint and 1 part water. I contacted Leyland and they told me to do what it says on the tin.

 

[KenGMac]

harlow, good evening.

Industry standard is 10% for a so called "Mist Coat" [water down by 10%]

The general standard is Mist + 2 full coats

Ken

 

[sparkwright]

Some people here recommend around 20, 25 even 30%.

Can anyone compile a comprehensive list, subject to different emulsions ranging from trade paint, vinyl silk, and dishwater thin DIY shop paint?

 

[KenGMac]

There is no absolute definitive answer.

All depends on a series of variables, Type of Emulsion. manufacturer, state of the plaster, Bla, Bla, Bla it goes on and on

The object is to account for the so called "suction" of the plaster where the wet paint dries too fast because the plaster simply grabs the moisture in the Emulsion and the paint film dries to fast causing problems, hence the need to water down the first coat. Trick is to use a Matt emulsion for the first "mist" coat

 

[sparkwright]

I'm told DIY shops now sell 'mist coat'. Is this likely to satisfy most if not all bare plaster situations?

 

[harlow]

harlow, good evening.

Industry standard is 10% for a so called "Mist Coat" [water down by 10%]

The general standard is Mist + 2 full coats

Ken

I've also seen people say give 2 mist coats. I watched a video where they said they used trade matt at 70/30 but when they painted it on the wall it looked like skimmed milk so they gave it 2 mist coats.

Some people here recommend around 20, 25 even 30%.

If you ask google it says to use a 70/30 ratio. I've watched a few decorators on youtube do a mist coat and it always covered well so when I asked what ratio they use most said between 20-30% but they wouldn't recommend using a 50/50 ratio as you won't get much opacity.

 

[JohnD]

I use 2 mist coats with masonry paint on concrete because it is so hungry it suck the moisture in.

Plaster is not so bad but I may do on chases and patches because you have to get the absorbency down to match the rest of the wall or the texture will look wrong.

 

[JP_]

Do what it says on the tin. I use Delux, which is 1:4 I think, but did once use Crown that was 50:50 - never again, I had more wash than the walls!

 

[opps]

I don't understand why some people seem to think that they know more than the manufacturer.

With Dulux Trade over new plaster, I follow the instructions (9 to 1) and then do a "wet on wet coat". The plaster effectively gets one and a half coats in one hit. I don't need to do that but I hate leaving a wall looking patchy. When the client gets home I want them to see a wall that is pretty close to being finished.

I also want them to look a the dust sheets and "marvel" at how clean they are. If you over-thin the paint it will splatter all over the place. I want to go to work in the morning with no paint on my clothing and leave site without any paint on my clothing. I got pulled over by a plain clothes policeman a couple of years ago, he asked me where I had been. I told him that I was decorating a house 300 metres away. He clearly didn't believe me until he looked down at my boots and saw a tiny bit of paint splatter on them. I now refuse to clean my boots, just in case.