paint on fresh plaster?

[toffee]

I know you shouldnt ask same question twice but originally I asked several questions in one post and got replies for most questions... but please.. please.. can I ask again..?
when can I paint on to of new plaster?
and how many coats will I need to do befor achieving colour I want? I want a natural biscuity colur eventually.. so can I do a cheaper white paint first then a final coat of the colour I want?

 

[toffee]

sorry to those of you for whom speling /grammar matters... Im tired after work and just fired off question.. I see it contains mistakes.. careless typing !!!

 

[Zampa]

Toffee...if you have read a few of our relies you'l have noted that spelling and grammer obviously doesnt matter!!

When can you paint plaster?.......obvious answer...when its dry!...if its just a skim over then it should be dry in a few day...if its deep plaster then it could take a whole lot longer.

Its ok if you use heat to speed it up...but beware...the heat may only dry the top couple of millimetrs...take the heat away and any dampness underneath will be drawn to the surface again...big problem if you paint it too soon.

Talking of which...the best system for painting new plaster IMO is....

Dry scrape the whole wall to remove any splashes of plaster...

Apply a mist coat (the amount you thin it deepends on the quality of the paint you have)

Rub it down with 100 grade abrasive paper

Paint another coat...again thinned by about 30% (deepening on the paint)

Then give it a fill coat

Its a good idea to use cheaper stuff for the mist coat.

Oh and stick to matt emulsion.

And if the walls are thick with plaster you shuld use contract matt to allow any trapped moisture to escape

 

[Nestor_Kelebay]

Toffee:

If the plaster you're talking about is gypsum based joint compound, then it's as Zampa says "when it's dry".

However, if this is real lime based plaster, it's highly alkaline, and you should actually use a primer meant for fresh concrete over it. Probably any PVA based primer would work OK, but if it's real lime plaster it's not a good idea to use an oil based primer on it at all. The reason why is that oil based and alkyd primers will react with a strong alkali to form soap, thereby causing the primer to actually turn into soap and lose adhesion with the wall. Both new concrete (less than a year old) and fresh lime based plaster will both be too strongly alkaline for oil based primers, and you really shouldn't use a PVA primer on them either. Best to use an acrylic primer meant for fresh concrete.

Look up SAPONIFICATION in the Encyclopedia on this British version of the Paint Quality Institute web site:

http://www.paintquality.co.uk/encyclo/

 

[Lower]

when we decorated our lounge last year we had the walls skimmed. We used a cheap white watered down by about 25% emulsion to provide a base coat and then two coats of 'beige' paint for want of a better description. Coverage was fine.

To be honest, with the paint we used, i think we could have got away without using the base coat as the plaster covered very easily and there was little to no absorbtion.

I know you shouldnt ask same question twice but originally I asked several questions in one post and got replies for most questions... but please.. please.. can I ask again..?
when can I paint on to of new plaster?
and how many coats will I need to do befor achieving colour I want? I want a natural biscuity colur eventually.. so can I do a cheaper white paint first then a final coat of the colour I want?

 

[Zampa]

when we decorated our lounge last year we had the walls skimmed. We used a cheap white watered down by about 25% emulsion to provide a base coat and then two coats of 'beige' paint for want of a better description. Coverage was fine.

To be honest, with the paint we used, i think we could have got away without using the base coat as the plaster covered very easily and there was little to no absorbtion.

Now I would worry about that...plaster by its nature is absorbant..unless its been 'polished' when it goes on (painters nightmare!)..if this is the case (which i hope it isnt) expect flaky paint one day...its always better to give the walls a mist coat and two more for a few reasons really...

1...It will show up surface defects

2...It locks paint to the surface as opposed to sitting on it..

3...It will allow you to rub the wall down witout scratching it

4...You use less of the top coat paint

5...The paint will go on easier

6...Youl end up with less of a texture in the final coat.

I know you shouldnt ask same question twice but originally I asked several questions in one post and got replies for most questions... but please.. please.. can I ask again..?
when can I paint on to of new plaster?
and how many coats will I need to do befor achieving colour I want? I want a natural biscuity colur eventually.. so can I do a cheaper white paint first then a final coat of the colour I want?

 

[toffee]

Im not sure what type of plaster it is. It is a just built extension onto existing stone house. It looks to be dry now (been plastered about one week, though it seemed to take much longer around where the electric sockets are...? any way, ( do excuse my ignorance ) when you talk about thinning do you mean adding water to matt emulsion paint? will it tell me on the tin how much to thin it by? I know Im asking for an idiots guide but I'd rather ask and get it right than save face and make a mistake.

 

[Zampa]

We all have to start somewhere toffe...

Yep..thinning with water..it will ay on the tin..(normally 10%)...depending on the paint and the reason your thinning it

Best way to do it is ...pour the paint into a container..then pour about two inches of water into the tin (if its a 5 litre tin) and the then stir everything thats left in the tin into it...then pour that into the container.

If your doing a mist coat then id go fo about 30% water

 

[toffee]

thank you, much appreciated. toffee