Mist coat on old plaster

[Chrix]

Hi all, I am thinking of mist coating using the Vinyl Matt with a 70/30 - paint/water mix as mist coat. think this mix is better than the tin's 10 parts to 1 part water?

 

[JohnD]

crazing

might have been residue of wallpaper paste. Did you scrub and towel it off?

I find a broad metal scraper is good for getting most of it off once you have wetted it enough to turn it to slime.

 

[Chrix]

there was never wallpaper on the walls, but the plaster does seem to have a wet slimy feel when wet... I just need to fill some holes and start mist coat process but not sure in Contract Matt best on old plaster or if best to do vinyl matt mist coat.

 

[JohnD]

some people put glue on plaster.

 

[opps]

Hi all, I had crazing over my first attempt to paint my bedroom walls and can only assume this was down to bad prep of painting vinyl matt on top of silk paint. Even though i did sand walls before hand.

Now I have gone back to the old plaster. I am fairly sure it is now all dry. I am thinking of mist coating using the Vinyl Matt with a 70/30 - paint/water mix as mist coat. I have done some research and think this mix is better than the tin's 10 parts to 1 part water? I am almost 95% confident this is best solution. Rather than mixing contract matt as a mist coat, followed by vinyl matt. any wisdom would be great please? Really hoping my next steps are right ones?

I was told not to use contract matt by one person as can be chalky on old plaster.. leading to the Johnstone's vinyl matt not sticking? but it does seem several people say that vinyl matt can create a film and this can cause problems down the line.

Did you initially use contract emulsion over the vinyl silk? Contract paints should only be used over new plaster. They are "inferior" paints that have a lower acrylic/latex content and are designed to be used on walls that are not completely dry. A decent quality matt should not have crazed

70/30 mist coat? The primary purpose of a mist coat is to reduce the level of suction in the plaster. Matt emulsions differ in thickness from one manufacturer to another. I tend to follow the advice of the manufacturer rather than some bloke on youtube.

I do agree that you will be better off using dilute matt rather than dilute contract matt as a mist coat.

Oh, and the thinner the paint- the more the paint splatter...

 

[Chrix]

Initially I sanded down the silk paint, then I put on a primer, followed with dulux emulsion and finished with Johnstones vinyl matt.. on reflection probably I should have put on the primer not the dulux but I thought I was preparing the area properly.

As such, I am now thinking of doing 70/30 or Johnstones Vinyl Matt as mist coat (as I have now stripped all old paint off and one back to the plaster). the advice on the tin says to mix 10% water but feel that could be too thick still.

I followed advise from the decorating centre first time round and ran into problems, this is why I am hoping for more professional advice here?

 

[Chivas69]

I'm wondering if originally the plaster has been pva'd before being painted. Is the plaster quite shiny?

 

[Chrix]

No wouldn't say overly shiny... did seem shiny when wet but maybe that is normal.

 

[JohnD]

I put on a primer

what primer?