plaster arch - how to seal and paint

[philipchild]

Hi,
I am currently renovating part of a Georgian house and have stripped layers of paint from an arch which appears to be made from some sort of plaster (of paris?) I have tried cleaning loose dust from the arch and painting it abut as soon as the paint starts to dry it peels off. I have tried this twice now, once with very watered down undercoat, with no success. I am really scared that I will do permenant damage to the arch if I try again. does anyone know what I should use to seal the arch and paint it with? It seems so soft and crumbly it's impossible to remove all dust.

thanks,

Philip

 

[hoppy]

What did you use to strip the paint ??

 

[Moo]

What did you use to strip the paint ??

- there's always a chance that you didn't neutralise whatever you used.

And, of course, there's the question of what you tried to paint it with. More information, please!

 

[philipchild]

Sorry for the lack of info, I used kling strip to strip the paint and used a vinegar solution to nutralise. Then I tried painting with matte emulsion mixed with 50% water to try to soak in. Possibly I didn't use enough nutrilzer or possibly I need to seal the plaster somehow. I don't have much experience with this sort of thing. The paint starts to peel within 10 minutes of finishing a coat...

 

[Schoolmarm]

"Before repainting, make sure that the surface is completely dry and free from any efflorescence. The appearance of efflorescence usually indicates that the washing off of dissolved paint residues has not been thorough enough.Use an alkali-resistant primer."



Taken from strippers of sudbury site.
Did it say to use vinegar?

I suppose distemper or limewash are the correct things to use in which case I don't know anything about priming for those. Nigel Watts will know I bet.

 

[philipchild]

Did it say to use vinegar?

Yes, a white vinegar solution, but I was a bit timid with it as I wasn't sure how the vinegar would effect the plaster arch. When I began stripping it I had assumed it was made of wood. It's the top part of a frame, the rest being made of wood.
So I planned on painting it all with a standard Dulux oil-based eggshell paint. I had assumed I would need some sort of first layer of watered down emulsion to seal the plaster in the way that newly plastered walls are treated. I don't think I can ever remove all the dust from the arch prior to painting as even a gental brush against it will create more dust as it's so soft.

Thanks for your replies so far...

 

[hoppy]

Unfortunatly kling-strip burns plaster, You would be better off cleaning the residue with "Sugar soap".
Dont worry to much about the damage...easily repairable with casting plaster

 

[Pford75]

I'd suggest that finishing with distemper or limewash is a much better solution than 'sealing' or similar. Distemper is easy to apply, won't peel off, comes in multiple shades and will be easy to remove in the future if required

 

[jocelyn plummer]

You might find this website for distemper and paint finishes and application helpful.

www.rose-of-jericho.demon.co.uk

 

[skier-hughes]

"
Taken from strippers of sudbury site.
Did it say to use vinegar?

On their site they advise to use their own neutraliser, but if you speak with them on the phone they advise the use of a vinegar and water mix as it's lots cheaper.

 

[Schoolmarm]

Oh that's ok then. I wondered if the vinegar was degrading the plaster.

 

[robgil]

if i were you i would try a mist coat first , 3 parts water and one part matt emulsion. roller it on and allow to dry fully then take care on the next coat not to pull it back off again. you also may find a pva based primer will work , or watered down pva as a last resort. there are quite a few primers out there suited to do this job.

if your walls need to breath then you may need something a bit more specialized,what are you painting it with? and when you say its 'crumbly' are you sure its not damp? any pics?

 

[Schoolmarm]

Rob :shock: noooooooooooooooo. DISTEMPER or LIMEWASH 8)

 

[jocelyn plummer]

I agree with you Schoolmarm. It probably would have been a distemper finish in the first place :wink: if so, that may account for the pickle Philipchild found himself in , as described in the first posting!

 

[robgil]

but wont distemper do the same thing unless the plaster is primed?

 

[jocelyn plummer]

There is a special primer for unpainted porous surfaces. It is worth consulting the specialist paint suppliers --

Potmolen, Rose of Jericho, to name but a couple.

The Georgian Group, and SPAB do leaflets on all sorts of things to help with listed building restoration.

 

[Pford75]

but wont distemper do the same thing unless the plaster is primed?

From the sounds of it, the problem the OP is having is not due to the plaster being unprimed....it's because there is some residue on the plaster.

Most of our plasterwork and ceilings have distemper on them and any attempts to emulsion simply result in huge patches of paint peeling off (When we first moved here and before I knew better I tried PVA and this simply delayed the peeling by 3-4 months).

Distemper is relatively cheap, easy and pleasant to apply and comes in almost any colour you would want....personally, I also happen to prefer the aesthetics of the finish to that of emulsion. I can buy the argument about practicality on walls etc (especially in high traffic areas), but on a ceiling or plasterwork it seems like a simple decision. I hesitate to mention their name, but F&B also do a distemper which I have used and been pleased with.