On Mon, 04 Oct 2004 10:52:17 +0100, Laurie wrote:

"VisionSet" wrote in message
...

AFAIK there is no chemical reaction occuring when gloss paint dries. All
that happens is the oil evapourates. Therefore soluble in white spirit
before == soluble after.
Mike W

Oil-based paints contain linseed oil which has unsaturated (ie double)
carbon bonds. These react with oxygen in the air and slowly cross-link
forming a polymer.
That's why you get a skin in a partly-used tin of paint. The air-gap will be
fully saturated with solvents within minutes of replacing the lid (so no
more evaporation occurs) but there's enough oxygen for the surface paint to
react with.

I've never known white spirit to dissolve dried oil paint. Maybe it was
brush cleaner?

After 60 hours (OP said) this seems extreme.
The evaporation of the solvent (White Spirit, Water or Xylene) is what
makes the paint become touch dry.
The polymerisation is what makes the paint film permanent.
This is hours for Vinyl and Acrylic.
This is a day or so for Polyurethanes and Alkyds
This weeks for the resin in Hammerite.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
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