painting over wallpaper border

[jamiller]

My friend has anaglypta which is to be repainted with silk emulsion. He has a paper border along the top, which he wants to paint over as removing will damage the anaglypta. Can I paint the silk straight onto this or should I put another paint on first? thanks

 

[Zampa]

yOU COULD GIVE IT A COAT OF UNDERCOAT FIRST TO HELP PREVENT THE PAPER BUBBLING..THEN EMULSION OVER

bUT IT SOUNDS LIKE ITS GOING TO LOOK A RIGHT OL MESS

OOp..s...caps-lock!

 

[jamiller]

I have explained it will look a mess, but, thats what they want to do !! I take it you mean some kind of quick drying water based undercoat ? Thanks

 

[Zampa]

No..oil based..if you put water based u/c on it it may have the same effect as emulsion

 

[jamiller]

yep - sorry for being a bit slow !! I get a little confused on water based and solvent based in regards to what reacts (badly) when putting one on the other - could you explain possible issues with regards to this? Thanks Zampa

 

[Zampa]

Sorry Jam I dont qut follow what you mean

 

[papergirl]

Im getting a bit lost now

 

[Zampa]

yep - sorry for being a bit slow !! I get a little confused on water based and solvent based in regards to what reacts (badly) when putting one on the other - could you explain possible issues with regards to this? Thanks Zampa

Did you mean putting emulsion over oil based unders?

 

[jamiller]

sorry for the confusion ! I was originally referring to if emulsion paint would react on top of the oil based undercoat. My mind then wandered on (somewhere) to more generally speaking which type of paints react with other types. Papergirl- please keep up !!

 

[papergirl]

Sorry But your still none the wiser

 

[Zampa]

So many different paint will react when used on others...the word 'react' is the key really...because they 'react' in different ways.

Pianting over a shiny flexible coating such as gloss with a non flexible paint like a water based matt will cause lack of adhesion, flaking and cracking...or 'crazing'..

Painting over a reversable coating such a bitumen will cause a different reaction...bleeding...where the tar based pigments will bleed though to the surface of the top coating.

Painting over a chalky coating such as disemper or limewash (whitewash) will cause the top coat to lift very quickly because your basically painting over powder..

Certain specialist paints such as two pack epoxy resin when painted over a ordinary coating can cause a reaction similar to paint stripper..

Ive seen Sikkens gloss lift a coventional undercoat..

The trade term is called incompatability..

Thats why its always best to stick to one brand..not that using say dulux gloss over crown undercoat for instance will cause a problem..but if there is any problem with it the paint manufacturers will always go back to the 'book' and defend their product by saying you should have used their paint as the top coat/undercoat..

 

[jamiller]

Thanks Zampa - great response. Thats the sort of thing I was getting at. I listen to you guys refering to issues with paint incompatibility, but my question was probably a little too broad! eg.-I stripped paper off my 65 bungalow and one wall was painted with gloss like paint. I tested an area of matt emulsion and it crazed terribly. I had to line. Also, I see you dont recommend matt over silk emulsion (not without prep). Papergirl - I am the one with the !!

 

[Zampa]

Matt over silk is ok 90% of the time..but if the silk is particular shiney then crazing problems may occur

 

[papergirl]

No worries Jams, it was a bit muddled, clear as mud now.

Only joking zampa.

 

[papergirl]

O.K Zampa, if this does happen,

Matt over silk is ok 90% of the time..but if the silk is particular shiney then crazing problems may occur

can it be sorted out without lining. Maybe just by abrading?