Vinyl Matt Mist Coat?

Discussion in 'Painters' Talk' started by Chrixrix, Jul 30, 2021.

  1. Chrixrix

    Chrixrix New Member

    Hi all, I had crazing over my first attempt to paint my bedroom walls and can only assume this was down to back prep of painting vinyl matt on top of silk paint. 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? Its taken me hours to sort and got tennis elbow in process so really hoping my next steps are right ones?
  2. Wayners

    Wayners Screwfix Select

    The application data sheet which you can read online for your chosen paint will tell you in simple English what you need to do.

    Retail paints tend to have that thixotropic agent added so can't be thinned but trade paints don't have the agent so can have 20% water added for mist coat.
    So depends on the paint used so read the data sheet.

    This explains the difference in emulsions
  3. AnotherTopJob

    AnotherTopJob Screwfix Select

    Mixing ratios aside, vinyl matt is not ideal as a mist coat as it will form a skin on top of the plaster rather than soak into it like the contract matt.
  4. Wayners

    Wayners Screwfix Select

    I should of added.

    If old plaster coat with gardz then emulsion over so no mist coat
  5. DIYDave.

    DIYDave. Screwfix Select

    You could have sealed over the crazed paint instead of sanding (?) it all back to plaster and giving yourself tennis elbow as a result

    Recent post on this subject about painting over silk paint but as usual, some people don’t get problems whilst others do

    I’ve painted over silk and had issues with paint blistering so last room I did at MIL, sealed over silk with Zinsser 123

    Little more work and expense but gave a great surface to emulsion over, using Dulux EasyCare and no problems

    No definitive answer to this one but plenty of suggestions :)
  6. Chrixrix

    Chrixrix New Member

    Thanks have now watched video so think going with mist coat of vinyl matt and 2 tops coats.. onto old plaster. Going once? Going twice? ...
  7. Wayners

    Wayners Screwfix Select

    Trade matt?
  8. Chrixrix

    Chrixrix New Member

    I have johnstones vinyl matt. Also I was given this rubber like filler for some cracks and holes on the plaster but when I put that on yesterday it seems like a rubber like sealant. So I have scraped that off .. can I just put on normal filler on holes? I don't want to add a plastic seal to the plaster. I am nervous I might mess up? I painted the rest of house fine. Just this one room is a problem. :(
  9. Wayners

    Wayners Screwfix Select

    Toupret powder filler will work. You want that type.
    Ready mixed can be a tad thin vs powder plus powder is faster drying and sets quicker
  10. DIYDave.

    DIYDave. Screwfix Select

    Sounds like you’ve used ‘caulk’ to fill the holes with ? In a tube you use with a gun like silicone I guess ?

    Great for filling cracks between joints like wall to ceiling, architrave to wall, and general gap filling. Can use for holes if you have nothing better suited but you can’t sand down caulk so better to use a filler made for the job

    I’ve used for years the Leyland Trade Matt Emulsion as a mist coat and never had an issue with it, both in prep and final finish - and although I’m diy, I would say I’m fussy about my finish and aim for a good standard

    Used it over new plaster, previously painted walls and to blank out a strong colour when having a total colour change

    Recently blanked over a lime green bathroom paint with a slight sheen with the Trade Matt then over coated with Dulux EasyCare - all good and no issues

    But what suits one person and one application doesn’t fit all so good luck with yours
  11. chillimonster

    chillimonster Screwfix Select

    the rubber filler sounds like a Toupret product which I used many years ago.
    Never quite set but also never cracked again.
  12. Chrixrix

    Chrixrix New Member

    Hi All

    The filler that was shinny and plastic like was flexible crack repair filler from brewers.. I have take most of this off now except the deep cracks.

    I am now going to fill all other cracks and holes with Toupret Interior Filler which I will mix up.

    The more I read the less I think doing a mist coat of Johnstone vinyl matt (even if I do have old plaster) is a good idea. I think it will rather not take or may take this diy trip but lead to problems in years to come.

    As such I am now thinking of Getting the Johnstones contract matt and mist coating with this? Is Johnstones or Leylands better? also, should I mist coat with a 70/30 split? and do I do 2 coats of the contract matt.. last question, if the contract matt is chalky, how does the vinyl matt stick to it afterwards?

    I really appreciate your help.. I enjoy painting generally but this has got the better of me. :0

    ps. I checked the data sheet for the vinyl matt but it seems a bit vague and the contract matt says to use on new plaster not old?
  13. Wayners

    Wayners Screwfix Select

    Contract matt is porous and ment to be applied to new plaster so over the next 6 months it can continue to dry out. This happens on new builds.
    After 6 month you need to lightly sand rough surface of the contract matt and mist coat it to seal with a vinyl emulsion or durable emulsion. Some durable emulsions require a primer while others are self priming.
    The video in posted above explains the over misuse of contract matt in the UK as a primer and just because its always been used as a base coat don't mean it should be continued to be used.
    The 2 main primers used are gardz or acrylic primer undercoat unless you want it to continue to dry out.
    Gardz is belt and braces as will neutralising any wallpaper paste or old degraded distemper.
    Acrylic primer will seal a little and be nice and smooth.
    Chrixrix likes this.
  14. Chrixrix

    Chrixrix New Member

    Thank you for all your replies .. I had used the Joncryl Undercoat and Primer the first time around but might of messed by then adding Dulux Emulsion coat prior to the Johnstone Vinyl Matt. I think as I live in a new build (20yrs old) that the walls couldn't have distempered? the plaster looks good and clean. I checked the Johnstone website this avo and it clearly says there to use the Vinyl Matt as mist coat.. but are you saying I could use the Joncryl Acrylic Water based primer and undercoat as another option? on their website it says this undercoat can be used on plaster and other substraits. I find this all very interesting - I never knew paint could be so interesting.. rather that, or I need to get out more :)

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