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"rrh" wrote:

I don't know that it does anything much at all other than slightly polish
the surface. If it doesn't attack the finish in any way and powders off if
you dust the surface, what use is it?

I think it does attack the finish. It certainly takes a bit of the shine off
gloss. The instructions say paint within 6 hours for best results. That
implies to me that it softens the finish or in some other way makes it
better as a surface for new paint.


Flatting gloss paint usually does soften the surface and there is a time
scale that the prepared surface should be painted within, it is not
unusual to paint within say six hours after flatting.
Fresh paint applied over the top will have a better bond during this
time scale (which differs with certain paints), the bonding will not be
as strong if the area is painted after the time scale and the prepared
paint has had time to fully harden again.

This is often called "breathing time" in the trade where a paint is
allowed to breath or harden usually after a good wet flatting.

Stephen.


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