Hi guys. i painted my window sills with sandtex masonry paint on my
window sills. Now it has flaked and just peeled off. Why is this? I
did paint over gloss, but should this have affected it?

Thought i'd go for the good stuff, but looks like i wasted my money.

wrote:
Hi guys. i painted my window sills with sandtex masonry paint on my
window sills. Now it has flaked and just peeled off. Why is this? I
did paint over gloss, but should this have affected it?

Thought i'd go for the good stuff, but looks like i wasted my money.

Doesn't matter how good the stuff is, you still need to have a decent
substrate, and gloss paintwork isn't it.

Presumably the cills are actually masonry ones?

I had a very similar problem myself recently - although I sanded down
the old gloss paint to key the surface, it didn't prevent the new
masonry paint flaking straight off. So I scraped and scrubbed it alll
off and started again; next time I painted over the old gloss with an
external grade, oil-based undercoat paint first. Then painted that with
the masonry paint later - seemed to work fine.

David

The message .com
from contains these words:

Hi guys. i painted my window sills with sandtex masonry paint on my
window sills. Now it has flaked and just peeled off. Why is this? I
did paint over gloss, but should this have affected it?

Yes, of course it affected it! It's intended to be painted onto masonry,
not gloss paint.

Masonry is textured and absorbant and rough and dimply. Even my
glosswork is smoother than that.

--
Skipweasel
Pay no attention to that man behind the curtain.

lavenders19 wrote:
Hi guys. i painted my window sills with sandtex masonry paint on my
window sills. Now it has flaked and just peeled off. Why is this? I
did paint over gloss, but should this have affected it?

It's probably because the sills are made of concrete (or stone) and
are damp to some slight extent. The moisture in the material will
blister the paint as it tries to escape. You might do better to
strip the sills entirely, and re-do with a "breathable" paint
(Sandtex ultra smooth, for instance).

ok guys, seens like i need to remove the gloss paint first. How do i go
about this... will nitromors paint stripper do?

wrote:
ok guys, seens like i need to remove the gloss paint first. How do i go
about this... will nitromors paint stripper do?

If it's onto masonry, it's likely to be very hard to shift via any means
(surface being textured/porous) which is why I went for the method I did.

David

Chris Bacon wrote:
lavenders19 wrote:
Hi guys. i painted my window sills with sandtex masonry paint on my
window sills. Now it has flaked and just peeled off. Why is this? I
did paint over gloss, but should this have affected it?

It's probably because the sills are made of concrete (or stone) and
are damp to some slight extent. The moisture in the material will
blister the paint as it tries to escape. You might do better to
strip the sills entirely, and re-do with a "breathable" paint
(Sandtex ultra smooth, for instance).

Another good trick is to use a watershield type coating before painting.

wrote:
ok guys, seens like i need to remove the gloss paint first. How do i go
about this... will nitromors paint stripper do?

Yup.
Pretty much., And a wire brush, and a pressure washer if you can
beg/borrow/steal/buy one.

I think my best bet will be to 1)use a wite brush to remove as much of
the flaking paint as possible.
2) Paint the sill with "external grade, oil-based undercoat paint"
3) Repaint with masonry paint

Only one question. Where do i get this "external grade, oil-based
undercoat paint" from and does it have a more common name. Isn't
exterior gloss external grade, oil based paint. How would it being
undercoat, rather than topcoat affect it?

On 29 Mar 2006 03:05:49 -0800, wrote:


Only one question. Where do i get this "external grade, oil-based
undercoat paint" from and does it have a more common name. Isn't
exterior gloss external grade, oil based paint. How would it being
undercoat, rather than topcoat affect it?

Try a trade decorator centre, Crown (owners of Sandtex) or Dulux
perhaps. (You could also ring the tech advice line - the number's on
your Sandtex can.)

wrote:
I think my best bet will be to 1)use a wite brush to remove as much of
the flaking paint as possible.
2) Paint the sill with "external grade, oil-based undercoat paint"
3) Repaint with masonry paint

Only one question. Where do i get this "external grade, oil-based
undercoat paint" from and does it have a more common name. Isn't
exterior gloss external grade, oil based paint. How would it being
undercoat, rather than topcoat affect it?


It's just standard "undercoat" i.e. not "quick drying". Available in all
the sheds. Often the instruction to wash brushes in white spirit is all
that indicates it's oil based.
If the sills are going to be white, I wouldn't bother with masonry paint