Help with skimmed walls and use of a primer/undercoat

Discussion in 'Painters' Talk' started by Novice, May 12, 2012.

  1. Novice

    Novice Guest

    I know there is a lot of advice about this, but as a beginner, I need advice on whether I should continue with Sanderson primer/undercoat (I think it's oil-based) straight onto the walls (they are fully dry). This stuff is very thick and cannot be diluted - seems wrong to use it on the plaster. I have painted a small patch only and don't know whether to continue. If not, what should I go over it with, to ensure the end result does not look patchy over the area where I used this primer. thanks.
  2. StinkNugget

    StinkNugget Member

    Wow, where to start...?   First up, why are you putting primer/undercoat onto plaster?  Oil based primer/undercoat suggests it is for trim, ie wood.

    Are you trying to paint onto fresh plaster/skim or previously painted plaster walls?  If fresh plaster give it a mist coat followed by 2 coats of emulsion in your chosen colour.  A mist coat is just a coat of emulsion diluted with 20% water (use white as it's a base for whatever colour the walls are intended to be).  Some people say use Dulux Supermatt but really any standard white matt emulsion will do the job.

    Have a look round to see if there's any filling required, yes even on fresh plaster :)  After applying the mist coat, rub down with 80 grit paper to take off any rough bits & fill in where necessary - it's well worth having another look after the mist coat as it's easier to see where needs filling.  After any filling rub down again to get a smooth finish where filled.  I use Red Devil One Time.

    If you are painting onto previously painted walls, do as above but a mist coat is not required (ie fill where needed, rub down then apply 2 top coats).

    Regards to the oil based primer/undercoat you've painted onto the wall already, when dry just rub it down with 80 grit paper to get it smooth & to give a key for emulsion to grip to, then paint over with your 2 top coats.

    By the way, you can thin oil based products with a tiny bit of white spirit but I've never needed to do so with primer/undercoat.

  3. leonmuriel

    leonmuriel New Member

    just to add regarding one time filler..i always carry a tub..use mainly for emergencies now..can flash through quite strongly so needs spotting or bringing for mist coat i nearly always do 2 coats to balance the porosity of new skim, thats my prefered aproach, then 2 coat finish..i think alot of people are mislead regarding specialist primers.
  4. Dafty DIYer

    Dafty DIYer New Member

    get a painter and decorator in . Its a semi-skilled trade is painting ya know.
    You wouldnt try building your own house if you wernt a builder would you?Pay a painter the going rate and you will see the diffrence in quality,painting can be tricky yes but i do believe it is one of the easiest "trades" to pick up in a short space of time.guud luck
  5. Novice

    Novice Guest

    Hey that is a great reply. Thank you. Luckily I only messed-up a small area before I realised it just wasn't right, so will rub it down.
  6. Novice

    Novice Guest

    Thank you for the reply. I don't disagree with you. In another life I would be happy to train-up as a professional and expert Decorator - I admire good workmanship and fine detail. The problem I have is funds are stretched, otherwise I would hire somebody. So what is the going rate to decorate one standard bedroom from scratch (ceiling, coving, walls and skirting) ?

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