20066236 Painting Tips

8/3/2019 20066236 Painting Tips

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PAINTING TIPS

-MOST FREQUENTLY ASKED QUESTIONS

How Much Paint do I Need?

Which is the Right Finish or Gloss to Use?

How Can I Tell What the Color Will Look Like on the Wall?

How Many Coats of Paint do I Need? Which is Better - Oil-Based or Latex-Based Paint?

Can I Use Latex Over Oil Paint?

How Do I Prepare the Surface Before Painting?

What are the Best Tools to Use?

Can you Give Me Some Good Application Tips and Techniques?

How Can I Get Paint to Stick to Hot Surfaces?

How do Product Warranties Work?

How Much Paint do I Need?

In general, legitimate professional painters figure a gallon of paint should cover about 200 sq. ft. with a

paint coating averaging 2 mils dry film thickness over a very smooth, completely sealed (primed or

previously painted) interior wall surface. To figure the amount of paint to buy, multiply height bylength of all walls and ceiling (inside or out) for total sq. ft. Then divide by sq. ft. per gallon coverage

recommended on paint label for gallons needed. It's usually smart to buy some extra paint so you have

some left over for touch-up later. Normally, the better the paint, the more sq. ft. coverage you will get

per gallon.

Which is the Right Finish or Gloss to Use?

A flat finish is matte and light absorbent. It hides surface flaws well, both inside and out, but has

relatively low washability. Generally a flat finish looks better in less abused rooms such as the living

room, dining room and bedrooms, and it is perfect for ceilings because they usually don't need to bewashed very often. Satin finishes or semi-gloss enamels have a slight sheen and good scrubbability.

Engr. Salman Ali SyedSaudi Electricity Company

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8/3/2019 20066236 Painting Tips


They are better in rooms subject to more humidity or wear and tear, like the kitchen, hallway, bathroom

or laundry room. High gloss paints are very shiny and light-reflective, and are ideal for doors and trim.

On an ASTM scale of 0 to 100, 0-15 is considered "flat"; 5-20 is considered "eggshell"; 15-35 isconsidered "satin"; 30-65 is considered "semi-gloss"; and 65-100 is considered "gloss".

How Can I Tell What the Color Will Look Like on the Wall?

A color's appearance is affected by what is near it, like drapes, carpet, woodwork, etc. The type and

amount of lighting, both natural sunlight or artificial light from lamps, also has an effect on color ...that's why a color looks different from night to day, or in natural or incandescent or fluorescent light. In

general, a color will appear a shade darker on the wall than on the small color chip.

If a ceiling is of normal height and has light fixtures built in or attached directly to it, white is the best

color choice. White has the highest light reflectance and will provide maximum illumination fromlighting fixtures. Lighter, cool and neutral colors should be used on most walls. These colors have high

reflectance which aids in illumination and contributes to a feeling of spaciousness. Doors, moldings

and unique architectural features can use complementary colors to add accent or break the color

monotony.

How Many Coats of Paint do I Need?

Buy top quality paint and apply the paint generously, avoiding excessive spreading, and you'll cover

most pastel colors in one coat. It is always better to apply two (2) thin coats rather than one (1) very

thick coat. Basically, there is no such thing as a good one-coat paint job . . . sometimes you can "get

by" with one coat, but only if the surface has already been painted, and you use the existing paint coatas the "prime" coat for the new paint job.

Which is Better - Oil-Based or Latex-Based Paint?

Generally, you'll want a latex-based (water-thinned) primer over stucco, drywall or plaster, and an oil-

based (solvent-thinned) primer over wood and metal.

For your finish coat, especially for exterior exposure, a high quality acrylic-based paint will usuallystand up to ultraviolet light (sunlight) much better than an oil-based (solvent-thinned) paint.


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8/3/2019 20066236 Painting Tips


Can I Use Latex Over Oil Paint?

Yes you can, and you can also use oil over latex. Just make sure the surface is properly prepared bythoroughly cleaning and sanding to remove any gloss finish if necessary. It's not the kind of paint you

choose that's important - it's how well you prepare the surface before you apply the paint. Proper

surface preparation is the secret to every successful paint job.

How Do I Prepare the Surface Before Painting?

You always want the surface to be completely clean, smooth, totally gloss free and dry. Make repairs to

all surfaces so they are smooth and free of holes and cracks. Dust all surfaces. If dirty, wash with

cleaner to remove grease and grime. If the walls are "glossy", the surface can be made non-glossy byroughening and thus dulling the surface with sandpaper, or by chemically preparing the surface with a

"liquid sandpaper."

On exterior surfaces, scrape and remove any flaking paint. Use wire brush on porous surfaces. Surfaces

should be clean, dry and free from any contaminants before painting.

Mildew MUST be killed prior to painting. For the best mildew treatment, scrub the surface with a

solution of one part bleach, three parts water, plus 3 ounces of tri-sodium phosphate, and 1 ounce of

laundry detergent. Wear rubber gloves. Then rinse well with fresh water and let dry completely before

painting.

What are the Best Tools to Use?

Choose a roller with an extension handle. It should have a stiff frame that won't flex and leave an

uneven coat. For smooth surfaces, use a flat nap roller; for rough surfaces you will need a longer nap.

Use metal trays that won't bend and spill paint when you pick it up.

Polyester and nylon brushes are suitable for all paints. Use angle-cut sash brushes for getting into

corners and painting to a line. Square-cut brushes are for door panels, wide trim.

Can you Give Me Some Good Application Tips and Techniques?

Paint ceilings first, and apply a 2 1/2 inch band around ceiling with brush where roller can't reach.Before it dries (give yourself about 20 minutes), roll paint on, working parallel to longest wall in small

patches.

For painting walls, outline corners and trim with your brush first. You can save time before the paint


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8/3/2019 20066236 Painting Tips


dries by using the extension to paint the entire wall. Roll upper third, step back for center, then step

forward to roll bottom.

While painting, dip your roller in the paint, but never submerge it and get paint inside the roller causingruns and drips. Dip frequently and don't be stingy or you won't get even coverage.

If you're using latex paint and you plan to continue painting the next day, wrap rollers, brushes and

pads in plastic or in plastic bags and put them in your refrigerator. They won't dry out and can be re-

used.

How Can I Get Paint to Stick to Hot Surfaces? The Pancake Griddle Effect!

The Potential Problem

Paint adhesion to hot surfaces, especially during summertime hot weather.

The Solution

When applying any paint, including both waterborne (so-called "latex") and solvent borne, including

alkyd (oil-based), rubber-based, epoxy-based, urethane-based, etc., always make sure the surface to

which you are applying the paint or coating is NOT TOO HOT - i.e. the surface should NEVER be 90°

F (32.2° C) or hotter. Note: The surface is frequently hotter than the ambient (air) temperature.

The Reason Why?

In order to get good adhesion of any paint or coating to any surface, the surface MUST be (A) rough

(like rough, 80-grit, sandpaper) and/or (B) porous (have pores in the surface, like the pores in a piece of

wood or lumber). This requires that surfaces be properly prepared, e.g. concrete must be made porous by being etched with acid and sheet metal, such as steel,aluminum, copper, etc., must be scarified or

roughened until it has a profile (peaks and valleys) measuring 2 to 3 mils (50.8 to 76.2 microns) from

highs to lows; even smooth enamel paint must be roughened with sandpaper.

The reason for the rough and/or porous surface is so the paint or coating has something to grab onto to

hold itself onto the surface, or to penetrate into and anchor itself to. The bond between a paint/coatingand the surface to which it is applied is a mechanical bond - not a chemical bond.

When the surface is too hot, i.e. hotter than 90° F, then the paint will dry too fast on the back side of the

paint film - the side next to the wall, roof, patio or floor - BEFORE the paint has had a chance to

penetrate into the pores of the surface, e.g. the pores in the concrete or macadam surface of a driveway, patio, walkway, tennis court, wall of a swimming pool, or stucco walls on the exterior of a building or

the tiles on a roof. This is like pancake batter being put onto a hot griddle, and the bottom side of the

pancake that touches the hot griddle cooks much faster than the top side of the pancake. It cooks so

fast that in a few seconds you have to flip the pancake so it doesn't burn the bottom side of the pancake.


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If a paint or coating is put on a hot wall, roof, patio or floor surface, you get the same rapid drying on

the back side before the paint has the opportunity to penetrate into the pores, cracks, crevices, or the

roughened or abraded surface to which it is applied. The result will be a lack of adhesion to thesurface, which will eventually result in bubbling, peeling, flaking and chipping of the paint from the

surface

HELP!

Here's a TIP - If you are applying a "latex" (waterborne) paint, you can cool a hot wall, patio or roof by spraying it with a cool mist of cold water from a garden hose, which generally can lower the surface

temperature enough so you can apply the waterborne paint. But be sure there is no liquid water left on

the surface when you start applying the paint.

Of course, you cannot cool a hot surface with cold water if you are applying a solvent-borne (oil-based,rubber-based, epoxy-based, urethane-based) paint or coating.

Another thing you can do is to apply paint on the shady side of a building, not the side that is in thesun. Or, you can erect a canvas tarpaulin to keep the hot sun from hitting a wall by shading the wall.

Or, you can paint early in the morning when it is cooler, rather than later in the afternoon when it is toohot to apply paint.

BE SMART - DO NOT APPLY ANY PAINT TO HOT SURFACES -

YOU WILL CAUSE ADHESION PROBLEMS -

AND IT WILL NOT BE THE FAULT OF THE PAINT.

NOW YOU KNOW!

How do Product Warranties Work?

Warranties from legitimate paint manufacturers are limited to replacing the product or giving you your

money back and do not cover labor costs. Note: be very suspicious of any warranty that seems to offer you too much protection, no matter what you do or how you do it . . . Remember, a legitimate

manufacturer's warranty has been written by the manufacturer's attorney to limit the manufacturer's

liability . . . it was not written just to make you feel good about buying his product!


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20066236 Painting Tips