In article . com, Ether Jones
says...


Norminn wrote:
Ether Jones wrote:

Last summer I removed the treads from my exposed porch stairs, scraped
and wire-brushed them down to bare wood, let them dry in the sun for
several days, then painted them with an oil-based primer, and when that
cured, I applied a topcoat of latex labelled for use on exterior porch
horizontal surfaces.

Already this year, the paint (and primer) is flaking off in large
chunks. These stairs are exposed to sun and rain.

When I was applying the primer, I noticed that it was very "sticky",
almost like glue. At the time, I thought "man this stuff is great;
it's never gonna come off".

Now I'm wondering if perhaps a primer should instead be very thin, like
a stain, so that it soaks into the wood and gets a good toehold, and
provides a suitable chemical surface for tenacious adhesion of the
topcoat.

Is there such a product? Need brand name and product name.

If the wood was weathered, it should have been sanded down to new wood.
Did you use shellac-based primer? Dries fast.

I'm looking for a penetrating primer - one that will soak into the wood
like a deck stain does... not just lay on the surface. Does such a
thing even exist?


Possibly not - if a primer is formulated to bind to the surface and make a
paintable surface, the need for that quality would prevent creating a
formulation that would allow penetration as well. In order to penetrate, it
can't be stopped on its way by binding to what its passing.

I'm not a paint expert, but I'm a materials engineer, and this strikes me as be
one of those kind of problems which have an inherent tradeoff. But I may be
wrong...

Banty


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