The Guide - Primers & Paints
Many
professionals and experts agree that anyone considering a painting
project should use only top quality coatings. Top quality primers
and paints provide better durability and coverage, are easy to
apply, are excellent at resisting mildew, offer better colour
retention and a longer lasting sheen, and provide great value in
the form of lower long term maintenance costs. Cheap or low
quality primers and paints are less durable than top quality
primers and paints and fail prematurely due to changing
temperatures. Surfaces and coatings expand and contract with
changing temperatures, and low grade primers and paints do not
adhere well to well-prepared surfaces. Early repainting becomes
necessary when using inferior "bargain" and thinned primers and
paints.
The two basic components of coatings are pigment and vehicle. The
pigments provide colour and hiding power. Also found within the
pigment group are titanium, calcium carbonate, and silicate.
Titanium is used to form a film that bonds with paint binders
(resin), and together they are responsible for adhesion, providing
resistance against blistering, chalking and stains, and offer
superior colour retention. Calcium carbonate smoothes the titanium
out. Without the calcium carbonate, titanium would ball up.
Silicates provide hardness. These three ingredients are essential
to the pigments, especially titanium. The more titanium, the
better the paint. Vehicle is the binder and thinner of the paint.
The binder forms a film that holds the paint together. The most
common binders found in residential coatings are acrylic latex,
vinyl acrylic latex ( water base ), and alkyd ( oil base ) resin.
Always remember to never use one brand of primer or paint, over
another brand of primer or paint. Manufactures may formulate their
products differently causing adhesion problems. Repriming may be
required when a specialty primer is needed. Always follow the
manufactures suggestions on the products your considering.
Primers and Sealers
Primers and sealers are made with a high level of binders and are
made to perform a variety of functions. All primers and sealers
provide maximum adhesion for finish paints and make the appearance
of the finish coat even and uniform, offer durability and mildew
resistance, and seal surfaces to keep paint from being soaked up
by the surface. Some specialty primers and sealers include those
designed as stain blockers, rust inhibitors, vapor barriers,
useful in rooms where moisture is present, and for bonding, useful
for slick surfaces like glass, tile, Formica, or vinyl panels.
Latex primers and sealers may perform as well as oil primers and
sealers except on severely stained and heavily chalked surfaces.
Breathable alkyd primers and sealers offer far better adhesion
than acrylic latex primers and sealers and are highly recommended
for any paint project, including new or previously painted or
weathered wood, or new or previously painted ferrous metals. Rust
inhibited primers and sealers are highly recommended for metals.
Breathable alkyd primers and sealers will also penetrate wood
surfaces better than latex paints and are crucial for protecting
wood from water, because the alkyd binders form a tighter film of
paint. They should be top coated with one to two coats of acrylic
latex finish paint to minimize the risk of water penetration and
surface bleeding. This coating system also gives the longest term
protection against chalking by protecting against the ultraviolet
rays of the sun. Homeowners may want to consider tinting primers
and sealers the colour of the finish paint. This will allow the
finish paint to cover more easily.
Acrylic Latex Finish Paints
Acrylic latex finish paints dry quickly, provide great adhesion on
new and repainted surfaces, exhibit better colour and gloss
retention, offer better resistance from blistering, chalking,
fading and mildew. Additionally, acrylic latex finish paints offer
long term flexibility, giving better resistance to chipping,
cracking and peeling, resist alkaline deterioration found in
masonry, can be applied directly to galvanized metals without a
primer (although a primer is highly recommended ), and will
provide overall lower maintenance costs.
Vinyl Acrylic Latex Finish Paints
Vinyl acrylic finish paints are usually found in interior grade
latex paints. Never use vinyl acrylic finish paints as a
substitute for exterior paints or on masonry. The alkaline content
in masonry will degrade vinyl acrylic latex finish paints and
cause peeling.
Alkyd Finish Paints (Oil)
Alkyd paints offer good adhesion and can be applied at lower
temperatures than acrylic latex paints. They provide excellent
adhesion which is crucial for durability, especially on heavily
chalked surfaces, and interior and exterior surfaces with multiple
coats of paint. Alkyd finish paints are extremely durable on
interior trim. Some disadvantages to alkyd finish paints when used
on exterior surfaces are that they can get brittle and crack over
time, they have a tendency to turn yellow, they take longer to dry
than latex paints, and they do not hold colour retention or resist
mildew as well as latex paints. However, alkyd finish paints are
extremely durable on interior trim where they are not exposed to
the weather conditions. Alkyd finish paints should never be used
on new masonry or metals.
Paint Sheen
When homeowners are selecting a sheen for interior and exterior
paints, they should consider how much use or weathering a
particular area is going to get, and the look they are trying to
achieve. Flat sheens are considered the least washable, and on
exterior surfaces are not as mildew resistant as glossy paints,
but they are the easiest to touchup. Flat paints are also great
for hiding imperfections on surfaces. Glossy sheens are considered
more washable than flats, but show touchup marks. Any level of
gloss will show touchup marks and imperfections in the surface.
The use of a top quality acrylic latex primer will help in
reducing the sign of imperfections. Two coats of a non-yellowing
polyurethane is highly recommended for interior surfaces, after
painting is completed, for homeowners who want outstanding
washability and durability. The durability of a non-yellowing
polyurethane with eliminate the problems of touch ups and keep the
final paint project durable and looking new for a long time. |
