Just put up new Gyproc plaster coving in one of the bedrooms. In the past when using emulsion (vinyl silk) straight from the tin it took many coats to give a good coverage.
I think i have read on the forum that it is recommended that you should dilute the emulsion for the first coat and then revert to standard from the tin paint. If this is correct what ratio should the initial coat be thinned to ? And is this just for the one coat ?

Why does new plaster coving soak up the paint ?

Thanks in advance

Mark..

In article ,
mark harrison writes:

Just put up new Gyproc plaster coving in one of the bedrooms. In the
past when using emulsion (vinyl silk) straight from the tin it took
many coats to give a good coverage.
I think i have read on the forum that it is recommended that you should
dilute the emulsion for the first coat and then revert to standard from

I would suggest you use matt emusion for this first coat, not
vinyl silk. I normally use brilliant white, which is probably
fine unless the final paint colour is to be dark.

the tin paint. If this is correct what ratio should the initial coat be
thinned to ? And is this just for the one coat ?

It normally says on the tin. 10-20% water is a typical figure.
Just for the first coat.

Why does new plaster coving soak up the paint ?

It's porous -- the surface is paper and the plaster underneath
will soak up water too. The water helps the paint penetrate
into the surface before drying and bond better. Once dried,
the emulsion is waterproof enough to stop the water being
sucked out of the next layers, but also an excellent surface
for them to bond to.

--
Andrew Gabriel

mark harrison wrote:

I think i have read on the forum that it is recommended that you should
dilute the emulsion for the first coat and then revert to standard from
the tin paint. If this is correct what ratio should the initial coat be
thinned to ? And is this just for the one coat ?

Just played this game... did the first coat of matt emulsion mixed with
about 10% water, and then one more coat of undiluted emulsion. Did the
job nicely. If you skip that dilute coat then you may find you need
three to get a decent finish.

Why does new plaster coving soak up the paint ?

Because it is made from plaster and cardboard, both suck water like a
sponge!


--
Cheers,

John.

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mark harrison wrote:
Just put up new Gyproc plaster coving in one of the bedrooms. In the
past when using emulsion (vinyl silk) straight from the tin it took
many coats to give a good coverage.
I think i have read on the forum that it is recommended that you should
dilute the emulsion for the first coat and then revert to standard from
the tin paint. If this is correct what ratio should the initial coat be
thinned to ? And is this just for the one coat ?

Why does new plaster coving soak up the paint ?


Why would any paper covered plaster soak up water based paint? Because
it is porous!

MBQ