Mist coat paint lines - is it normal?

[Max Power]

I have attempted my first mist coat today. I am using Leyland Trade contract matt emulsion, with a 12" medium pile microfibre roller.

I used a mixing ratio of 50/50 for this. As you can see in the pic below, there are paint lines where I have applied the roller. Is that normal?

You might notice the cutting in areas are denser, this is because I have (not intentionally) used a lower mixing ratio here (something like 70 paint / 30 water). Is that going to be a problem when I come to apply the main coat?

Would really appreciate some feedback based on the pic above.

 

[JohnD]

Do it again.

 

[Chivas69]

70/30 won't be a problem. I may be wrong but from the picture it looks like you've got some roller edges on show. If you run your hand across the wall can you feel a lip where the roller has been.
You will always get some more dense areas on a mist coat where you overlap each band of paint. This is because a mist coat dries almost instantly so when you overlap the paint bands it's sort of getting a 2nd coat where the new band meets the previous band.
I also see missed plaster patches which will need filling.
I would do any filling that needs doing, sand off any roller edges and new filler and then mist it again with an 80/20 mix. Load the roller up but don't press too hard and if your roller leaves thick edges gently go over them as you go.

 

[JohnD]

50-50 is very thin, it soaks in almost immediately. If I use such a thin mix, e.g. on concrete, by the time I have got to the end of a wall I can go back to the beginning and apply a second. Working to and fro with a roller, in all directions, works away the lines before they dry

 

[opps]

Why did you do a 50-50 mix/ The back of the tin says

Seal absorbent surfaces with a solution of up to 1 part water to 9 parts Leyland Contract Matt

I recommend that you do it again with the correct (recommended) ratio.

Water based paints cure through a process called coalescence. As the water evaporates off, the molecules shrink down towards each other and bond together. If the surface, eg plaster, is porous, the water is sucked in to the wall rather than evaporating off. It messes up the coalescence process and can result in the paint being pulled off when the next coat is applied.

As a professional decorator, I hate leaving site with walls that look patchy. I do a wet on wet mist coat- I roll the new plaster and once I have finished the wall, I re-roll the walls (with the same mix) before leaving. It is kinda 1.5 coats. The walls look like they are almost finished. The next day, I do the first full fat coat.

I am not having a dig at you... but... you probably saw people on the internet that recommended 50/50 mix. Don't instantly believe every thing that you see on the like of youTube. Paint manufacturers have a much better understanding of their products than thickos on youTube.

 

[opps]

I would also add that pizzed out paint is incredibly splattery.

 

[Max Power]

Hi guys, thanks for the responses.

Why did you do a 50-50 mix

To be honest, there are so many differing opinions on this. I did watch a few YouTube videos where people were doing anything from between 30% to 80%, and all still achieving good results. I just decided to go with 50/50 to go with a middle ground ratio.

So, are you saying when I come to applying the main coat, that it won't bond to the mist coat very well? Or are there likely to be other issues?

Is there a way I can I test whether the mist coat I have done is of a satisfactory standard?

 

[opps]

The only real world test would be to apply a full fat coat and then when dry, apply another full fat coat (if it fails the roller will start puling the first coat of full fat paint off)... I would just follow the advice of the manufacturer, seriously, they know more about their paints than people on youtube.

 

[JohnD]

I can't see why you don't just apply another mist coat

Get rid of the patchiness, have a regular colour, texture and absorbency over the whole wall, ready for your colour coats

 

[Max Power]

Seal absorbent surfaces with a solution of up to 1 part water to 9 parts Leyland Contract Matt

Sorry to ask a silly question, but if I understand this correctly that means for every 9 litres of paint I should add 1 litre of water.

Thus, for half the amount of paint, i.e. 4.5 litres, I should add 500ml of water, right?

 

[Chivas69]

Yes, it's there or there abouts. If you accidentally do 85/15 it's not going to matter. Or even 80 /20 (8 litres and 2 or 4 litres and 1)
50/50 will work but you'd have to probably do it twice. Hence another mist coat will be sound enough.

 

[JohnD]

Sorry to ask a silly question, but if I understand this correctly that means for every 9 litres of paint I should add 1 litre of water.

Thus, for half the amount of paint, i.e. 4.5 litres, I should add 500ml of water, right?

Or another way to look at it (less measuring)

If you have a ten litre bucket

Put one litre of water in it

Then add paint until it is full

Stir very thoroughly

A plastic kitchen spatula is good if you are mixing by hand and easy to clean.

 

[opps]

Sorry to ask a silly question, but if I understand this correctly that means for every 9 litres of paint I should add 1 litre of water.

Thus, for half the amount of paint, i.e. 4.5 litres, I should add 500ml of water, right?

9 to 1 means dilute by10% (water).

As others have said, being slightly off won't make too much of an issue. I normally do it by eye.

 

[opps]

Or another way to look at it (less measuring)

If you have a ten litre bucket

Put one litre of water in it

Then add paint until it is full

Stir very thoroughly

A plastic kitchen spatula is good if you are mixing by hand and easy to clean.

In theory, correct but in practice if the volume of the bucket is to the rim, you wouldn't want to try mixing a full bucket.

That is one of the advantages of the paint scuttle, most have pint and litre (graduation) markings. Especially useful when mixing wallpaper paste.

 

[Notch7]

I am using Leyland Trade contract matt emulsion

I bought some of that to use as a mist coat.

Its truly awful paint, it’s not vinyl so it’s adhesion is poor and it has almost no pigment so it has poor opacity. As it dried it had areas which went really rough - by the time I had sanded it smooth, there wasn’t much left.

I’ve given up with it and I bought Dulux trade brilliant white - which has excellent opacity, almost obliterating the old colour with one coat.