In message
Lobster wrote:

On 05/07/2011 13:46, wrote:
In whill.co.uk
"Dave wrote:

On Tue, 05 Jul 2011 11:45:44 +0100, "Nightjar wrote:

With oil based paints, it ensures that the skin is under the paint, not
on top, when you come to use it.

But how do you then stir the paint to get the oil back in without
breaking the skin and get loads of bits in the paint?

With sufficient air space in the tin the oil paint will skin over
anyway, this will protect the remaining paint and depending on
the type of paint you are supposed to either cut off and remove
the skin then thoroughly stir or stir in the skin

What's the deal there - I never know what to do for the best when
I come across skin on paint. I usually make a judgement on
whether it will actually ever stir in, and if not (eg if it's an
eighth of an inch of hard dry crust!) I remove it.

It depends how thick the skin is, if it is thin then usually the
oil has not separated and you can just lift the skin off, If it is
thick and sat on separated oil then this oil should be stirred
back in and then strained to remove the bits of skin, this way you
don't lose the integrity of the paint.

What does it do to the quality of the paint itself? Would the
underlying paint become more (or less?) concentrated from repeated
removal of skin? Or is the skin layer identical in quality/content to
the liquid?

Oil paint is not resoluble so you have to remove the skin but
sometimes the skin is so thick and hard the paint underneath will
need that bit of medium that's still stuck to the base of the
skin.
Oil paint will become concentrated during use anyway as the
solvents or oil evaporate.

You can however add a little boiled Linseed oil if the paint
appears far too thick to be satisfactorily usable.

Stephen.


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