Robert Macy wrote:
On Nov 4, 2:08 pm, "dadiOH" wrote:
Robert Macy wrote:
On Nov 4, 6:27 am, "dadiOH" wrote:
...snip....
Why does that surprise you? If you overlap wet paint you are
retarding what was already there - partially dried - from drying
further. It will, eventually. In addition to difference in color,
you will also get a difference in sheen.

IIRC, you are painting over previous paint that is chalky. On an
old house. Lord knows how many coats of paint are on it but that
old, chalky paint is going to suck moisture out of the new paint.
Put on a coat, moisture is sucked; come back later and apply more
paint overlapping the old and you are going to get a stripe where
they overlap because the overlapped area has been sealed. Not hard
to understand. ...snip...

What?! retarding paint's drying changes its colour?

I didn't say that. I did say that paint can take many days to
completely dry/cure and that the color and sheen won't be uniform
until that time has passed.
__________



! Difference in
sheen I believe. But that's due to the surface gumming up. I used to
use Easy OFF Window Cleaner, comes in an aerosol spray can, to
lightly mist the surface of latex and be able to brush over any
variation making it uniform, but alas, they've discontinued that
product. Used to be able to use that product to go back hours later
nd still make corrections, too.

First, coat should be sensitive to what's underneath. That's why I
chose to water wash and physically scrub the old coat. Which did
show a colooured run off of chalky paint and dirt from wherever. I
saw a difference with the way the paint went on and recommend always
cleaning the base surface. But, the problem that prompted me to post
is NOT with respect to the first coat, but the second coat, which of
course is going over an almost acceptable surface of paint. Second
coat was actually an experiment. I don't want to do two coats on
this house, too expensive, and too labor intensive.

Let me try to clarify...

1. First coat over existing, old, chalky paint. Coat dries - dries,
not cures - relatively fast because old paint absorbed some moisture.

2. Second coat, partially lapping #1. The lapped part is a different
color and/or sheen because the first coat under it has sealed the
surface and the lapped part is drying/curing more slowly than paint
over the old, chalky surface.

--

dadiOH


I'm trying a new section that has been physically scrubbed with brush
and plain water. We'll see what happens over that.

Same thing...new paint will dry, next coat will dry except any overlap will
which dry more slowly. Ultimately, all will look the same assuming you
mixed the paint well.

Out of curiosity, why do you paint from the bottom up? Gravity is your
friend.

--

dadiOH
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