What paint to seal plaster

rach_k

This is the video https://www.youtube.com/watch?v=95k8UTzR9H8 I watched; he gets decent coverage too (around 4m30s in). Around 1m30s in he explains his choice of 50/50. Seems to have worked for us.

Welsh_and_proud

rach_k wrote: »

This is the video I watched; he gets decent coverage too (around 4m30s in). Around 1m30s in he explains his choice of 50/50. Seems to have worked for us.

In post 7 this is the person that I was talking about that used armstead trade contractt matt @50/50. He said he's painted a lot of new plaster in his time but the way he used the roller and the consistency of the paint I don't think he has. Also check out his other video where he repairs the paint that came off the wall in the house that he painted.

Doozergirl

The clue is in the word mist. You want the coat wet and it won't give good coverage. That's the idea. The point is for the thirsty plaster to get a good amount of water without sucking it all out of the paint itself.

If you use 100% paint, the plaster draws the water right out of it and you end up with a dry vinyl layer than hasn't created a bond with the plaster. When you put another coat on, the paint gets rehydrated and comes away from the wall, causing it to peel.

70:30 or 50:50, probably doesn't make a huge difference but 50:50 isn't going to do any harm, seems to be the accepted idea, and will ensure that the wall definitely gets enough water. Different paints are of different quality, I suspect that Wilko paint wouldn't be the same as Dulux Trade, for example, and probably already as a higher water content.

jennifernil

Having watched that video, I thought he got good coverage considering it was 50/50.

Using a roller on a pole I find is more awkward than using the short handle, and those sloping ceilings also make things more awkward, so I thought he did fine! Keeping further away from the roller is good when using thinned paint.

I also spoke with the plasterer and he said use 50/50. My OH has just done that on some new plaster, followed by a full coat of white, as that was going on the ceiling anyway, and then 2 coats of the chosen colour, and it looks very good.

rach_k

jennifernil wrote: »

Having watched that video, I thought he got good coverage considering it was 50/50.

Using a roller on a pole I find is more awkward than using the short handle, and those sloping ceilings also make things more awkward, so I thought he did fine! Keeping further away from the roller is good when using thinned paint.

I also spoke with the plasterer and he said use 50/50. My OH has just done that on some new plaster, followed by a full coat of white, as that was going on the ceiling anyway, and then 2 coats of the chosen colour, and it looks very good.

Agreed. It seems like the OP is very critical of everybody else's methods/choices but is the only one having to remove a mist coat :rotfl:

Mutton_Geoff

I wouldn't use a vinyl paint for a mist coat. Plaster takes ages to dry all the way through (even a skimmed plasterboard wall/ceiling has deeper filled in parts. I would use a non vinyl paint and still allow time for the whole lot to dry (possibly with heating and dehumidifier on at this time of year) then start with the vinyl based top coats.

Welsh_and_proud

rach_k wrote: »

Agreed. It seems like the OP is very critical of everybody else's methods/choices but is the only one having to remove a mist coat :rotfl:

The reason why I'm removing a mist coat maybe down to the plasterer and the only people telling you to do a 50/50 ratio is a plasterer and not a proper painter & decorator.

Welsh_and_proud

Mutton_Geoff wrote: »

I wouldn't use a vinyl paint for a mist coat. Plaster takes ages to dry all the way through (even a skimmed plasterboard wall/ceiling has deeper filled in parts. I would use a non vinyl paint and still allow time for the whole lot to dry (possibly with heating and dehumidifier on at this time of year) then start with the vinyl based top coats.

Do you know what brand paint that doesn't have vinyl in.

Mutton_Geoff

Welsh_and_proud wrote: »

Do you know what brand paint that doesn't have vinyl in.

Most of them, if you choose their basic emulsion (Dulux etc). I use Armstead Contract Matt White (same make as Dulux) as it's cheaper. I water it down with only 10% of water, others may dilute it more but I find that's just enough.


The pot even says "ideal for new plaster" on it

ceredigion

Welsh_and_proud wrote: »

The reason why I'm removing a mist coat maybe down to the plasterer and the only people telling you to do a 50/50 ratio is a plasterer and not a proper painter & decorator.

Why is it the plasterers fault?