All the answers to your questions are printed on the container instructions, however thin the first coat by adding approximately 10% water, I would also thin the 2nd coat the same personally.
Mist coat paint is simply watered-down emulsion paint, which acts as your primer. All you need to do is get some white emulsion paint and thin it out with water – it's that easy! Ten parts paint to one part water should work.
Thinning with ten percent water will vastly improve the coverage of the paint, this is convenient because it saves money provided you don't end up applying more coats.
Using too much water can lead to a loss of pigment and binding agents, making the paint less effective. Thinning for Detail Work: If you're using water to thin the paint for fine details, aim for a thinner consistency, but again, avoid exceeding 30% water.
To thin down emulsion ready for spraying, the best ratio is 70/30. That is 70% of paint and 30% water. Some painters prefer an 80/20 ratio, but this greatly depends on the paint you are using and how thick it was, to begin with.
When a painting contractor waters down paint, they are typically adding a significant amount of water to it. Think two gallons of water for every five gallons of paint. In contrast, the process of thinning paint involves a relatively small amount of water: 2-4 cups for every five gallons of paint.
Wet Film Thickness: This is the thickness of the paint when it's first applied, while it is still wet. Most paints require between 3-5 mils per coat.
How much water? You should add max 10% of water of the total volume of the paint.
For Rolling
Follow the same thinning instructions for brushing and rolling. Adding Floetrol when rolling can minimize lap lines. However, Otto doesn't recommend thinning with water when applying latex paint with a roller. “It doesn't give the look the manufacturer intends and can leave streaks,” she says.
The new plaster will be very absorbent and will suck the paint into the surface. Thinning the first coat with 10% clean water will help but the second coat will go much further.
All the answers to your questions are printed on the container instructions, however thin the first coat by adding approximately 10% water, I would also thin the 2nd coat the same personally.
Before use, flick the bristles back and forth to remove dust. Then moisten the brush in water if you are about to use water-based paint, or mineral turpentine if you are about to use an oil-based paint. Make sure you remove excess liquid before painting.
DIY beginners sometimes assume that one coat of wall paint will do – and end up with patchy or thin paintwork. Usually, you'll have to apply at least two coats of paint to achieve a smooth, even finish. Applying multiple coats also helps build up the paint so it's more durable, and less prone to chipping.
So watering down your first coat as a 'mist coat' will help the plaster to soak up the paint and create a bond between the new plaster and the paint.
On average, you can get about 400 square feet out of one gallon of paint. For an easy perspective, one gallon would likely cover a bathroom or small bedroom. But keep in mind that most rooms require more than one coat of paint. So if your room needs 2 coats, plan on getting around 200 square feet out of a gallon.
Too Much Water
You don't want to be too thin, but a mist coat needs to be thin—almost like a soup. The water will not seep into the substrate if the mist coat is too watery.
Some painters can dilute wall paint (but not to make it spread over a larger space or for economy), but because sometimes the wall surface requires a less thick application - but perhaps more coats).
Many painters “break in” a roller cover by priming it with water or thinner. In our lab we never prewet a cover before painting. If you choose to, you must spin it out with five or six strong pumps so it is only lightly damp. Then take even more moisture out by blotting the cover with a paper towel.
Always cut in first then continue painting with a roller. Cut in and paint with a roller one wall at a time. If you cut in all areas first and then roll the entire room, the paint that was applied when cutting in will have dried quicker and you will be left with a patchy, uneven finish.
However, a common ratio is 3:1 – 3 parts paint to 1 part water.
The bottom line is that watery paint is unusable. So if your paint is too watery and you attempt to use it to paint your home, you will notice that the paint won't adhere to surface correctly. It will be 'thin' and therefore will perform poorer than expected.
Paint needs to be thinned to a ratio of 2 parts paint to 1.5 parts water.
Check the thickness by running the paint through a funnel. If it flows freely through the funnel, you know the paint is thinned enough. If the paint is too thick, add an additional ⅛ cup of water (30 milliliters) per gallon (3.8 liters) of water and mix.
It's recommended to wait at least 24 hours before adding a coat of paint over your primer. Painting over it soon could cause your paint to adhere to the wall improperly, flaking and peeling.
The answer: don't worry that your single coat of primer looks bad. it's ok.