Mist coat not adhering

Discussion in 'Painters' Talk' started by TheScruffy, Oct 24, 2021.

  1. TheScruffy

    TheScruffy Member

    Hello

    I’ve mist coated newly skimmed landing, stairwell and hall. I mist coated I think 60 emulsion 40 Water. I’ve started cutting in the top coats and two things are happening. Firstly, in a very few places the paint is blistering where the new paint is being applied.

    secondly, when I’m cutting into the corners the paint the brush is lifting off the mist coat showing bare plaster.

    I’m assuming both these things are caused by the mist coat not binding properly to the plaster?? Did I cause this by applying too much mist coat so it didn’t look so washed out?

    I’ve also noticed that areas that I cut in last night and have dried, scratch off again really easily.

    I’m under huge time constraints but don’t want to rush it and find that a heavily trafficked area (hall and stairwell) will just get easily scratched within a short period of time.

    I have a couple of cans of Zinsser BIN, will this cure my problem if I apply that (I would have preferred to have used Albany Primer Sealer but they are closed today)

    will the Zinsser soak in and bind the plaster and toughen up the surface?

    Any help would be greatly appreciated.
     
    Last edited: Oct 24, 2021
  2. Jord86

    Jord86 Screwfix Select

    Is the plaster fully dry, what paint have you used for the mist cost, and roughly what ratio of water?
     
  3. TheScruffy

    TheScruffy Member

    Completely dry, around the window (outside the reveal on the wall itself) took ages to dry out after he’d skimmed. So much so the the galv bead began to rust. This is where the paint has blistered.

    I used Dulux retail for the mist coat and am using Dulux trade (white) for the top coats
     
  4. Jord86

    Jord86 Screwfix Select

    Deluxe retail what though, Matt, silk, eggshell, satin, gloss, creosote etc.
     
  5. TheScruffy

    TheScruffy Member

    White Vinyl Matt
     
  6. Jord86

    Jord86 Screwfix Select

    I don't believe you can use vinyl for a mist coat as it doesn't penetrate or allow the plaster to breathe, hence the issues you are describing. Matt emulsion is best or a specific emulsion designed to go straight on, Leyland super leytex obliterating emulsion springs to mind. @Wayners will be of more help than me.
     
  7. TheScruffy

    TheScruffy Member

    Thanks for your input.

    It was just standard vinyl Matt, I be used it loads in the past and not had this happen before. So if this is the wrong kind of Matt emulsion as a must coat I’m willing to learn.

    however whatever the cause I’m trying to work out if BIN will cure this and stabilise the substrate or have I got a bigger problem?
     
  8. TheScruffy

    TheScruffy Member

    Wayners or Astramax if you are out there, your help would be appreciated!
     
  9. Wayners

    Wayners Screwfix Select

    You haven't said which paint your using. Retail dulux (with dog on can) should not be thinned as has that thixotropic agent in but trade dulux can be thinned and used to mist coat.

    I always use acrylic primer undercoat which you can buy in B@Q and screwfix ect and add 10-20% water and use that to prime plaster.

    So many options and so many paints available you can get bogged down and lost with all the information.

    Read what the online data sheet says for the application of the paint you used over plaster.
     
  10. TheScruffy

    TheScruffy Member

    Thanks Wayners

    I can’t be certain which retail Dulux I used. It was their bog standard vinyl Matt.

    How do I get over the problems outlined above?

    can I use the Zinsser BIN ? Will it bind the mist coat and stop further blistering?

    I have a couple of cans to hand that I can use as long as it solves the issues.

    thanks in advance.
     
  11. Wayners

    Wayners Screwfix Select

    I'd stick to waterbased product.
    Acrylic primer undercoat.
    Get that on and leave to fully cure.
     
  12. TheScruffy

    TheScruffy Member


    Thanks, given my blistering when I apply a water based emulsion do you have any recommendations of a water based Acrylic?
     
  13. Wayners

    Wayners Screwfix Select

    Leyland is good stuff.

    Albany is also fine although they don't say that in documentation..

    Next up is gardz. That will really seal walls. Up to you which you use
     
  14. TheScruffy

    TheScruffy Member


    Wayners,

    out of interest is there any particular reason you wouldn’t use Zinsser BIN in this situation? Is it the solvent issue?
    If it binds and seals and I have the solvent filters for my face mask and I have two cans of it, would it do the job?

    or is it simply the wrong product? I thought solvent based may have avoided further blistering??

    if not I’d better head out to buy more stuff!
     
  15. Wayners

    Wayners Screwfix Select

    Yeah. It's the cost and smell plus no fun. It's a real lung killer
     
  16. TheScruffy

    TheScruffy Member

    Ok so as I have two cans of the stuff and the solvent filters….. will it bind the mist coat to the plaster?

    In other words will it do the job?
     
  17. TheScruffy

    TheScruffy Member

    And thank you for taking the time to get me out of a hole
     
  18. TheScruffy

    TheScruffy Member

    BTW … whatever happened to Astramax on here. He’s not posted since July… he was always posting advice.

    is he ok?
     
  19. Wayners

    Wayners Screwfix Select

    Yeah it will do job

    Think astra is gone..
     
  20. TheScruffy

    TheScruffy Member

    Left the forum?
     

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