- Home Improvement
How to Paint Your House(Part One) Choosing your tools
Determine the Type of Paint You Should Use
Now that you are an expert on almost every kind of paint and specialty coating there is, it's time to get down to work and actually apply them to real situations. The first step is, choosing the right type of coating for the specific surface and conditions that are present. To help you with this process we have included some handy charts that will make it easier to determine the appropriate product.
High quality latex paints with acrylic binders are a wise choice for the general indoor and outdoor painting situations. They spread easily, cover well, last a long time are quick to dry and easy to clean up.
Naturally, the first and most important factor in choosing a paint is whether the surface is an interior or exterior. Exterior house paint must be able to endure 100 degree heat, subfreezing temperatures, rain, wind, snow and various other conditions depending on the area of the country. Oil-based paints are a good choice when painting over difficult surfaces such as old paint that is heavily chalked. They can also be applied in colder weather than water-based paints. Interior paint must be durable enough to withstand household use, dirt and wear . To gloss or not to gloss, that is the question. With so many types of paint to choose from it can be a confusing task.
Along with advice from the local paint store or manufacturer, the following tips could be useful in your paint selection:
.,. Use flat paints on walls and ceilings anywhere you want a muted, low-reflection surface or where it is important to hide surface imperfections. Flat paints are best suited for low-traffic areas because it takes more effort to remove dirt and stains from these paints than from those with a higher sheen or gloss .
.,. Eggshell, sheen and satin paints are best suited for areas where a slight luster is desired, such as kitchen and bathroom walls, children's play rooms, hallways and woodwork. These paints are easier to clean and hold up better after repeated washing .
.,. Semigloss and high-gloss paints and enamels are most suitable for trim, banisters and railings, shelves, kitchen cabinets, bathroom and kitchen walls, furniture, door jams or any surface that you want to accentuate. A general rule is that the higher
the gloss the more it will highlight surface imperfections, so it is important to properly prepare the surfaces where a semigloss or high-gloss will be applied.
.,. When selecting an interior finish, consider choosing a water-based gloss enamel.
Water-based enamels have less odor than traditional high-gloss paints and are easier to clean up. They are also less prone to yellowing with age.
.,. Again, as with exterior paints, select a high-quality paint. It will perform better for a longer period of time.
Type of Surface
Generally the type of surface will be easy to identify, however if it has already been painted or is covered with other kinds of material it is best to find out what those other materials are in order to choose the best coating for the job. Also make sure that the surface does not have any special problems such as excessive moisture, staining or a coating that is incompatible with ordinary paints. We will cover substrate preparation later on in this manual.
How Much Paint is Enough?
Figuring out how much paint is needed for a specific job is essential and yet can be confusing, especially if there are odd angles, corners and indentations. All you have to do is simple multiplication and division; here are some helpful steps to follow:
The goal is to determine the total square footage of the area to be painted.
First - determine the areas of each wall surface you plan to paint: Measure and add together the width of the wall surface, including any smaller sections. Then multiply the total by the floor-to-ceiling height.
Example: 2 walls at 14' = 28'
2 walls at 11' = 22'
50' X 8'
400 Sq. Ft.
Second - Repeat the procedure for each room or area to be painted in the same color. Combine the square footage totals and divide by the paint's spreading rate which is always printed on the label. (typically this rate is 400 square feet per gallon)
Example: Room is 400 Sq. Ft.
Spreading rate 400 Sq Ft./Gallon
400 divided by 400 = 1 Gallon required.
To determine the square footage of the ceiling, simply multiply the width by the length. If it is the same color you are using to cover the rest of the room then combine the total ceiling square footage with that of the walls, then divide by the spreading rate.
Example: The Ceiling is - 14' long and 11' wide
14' X 11' = 154 Sq Ft.
400 Sq. Ft. + 154 Sq Ft =
Total Area 554 Sq Ft.
To find the footage of an odd shaped ceiling you first square it off and subdivide it into rectangles, using imaginary lines. Measure the dimensions of each rectangle then combine the totals, once again dividing by the spreading rate.
7X9' = 63 Sq. Ft.
7Xll'= 77 Sq. Ft.
8X9' = 72 Sq. Ft.
Total = 212 Sq. Ft.
Adjustments can be made for large areas such as doors and windows, by determining their square footage using the above methods, and then subtracting the figure from the total area. Most of the time it is best not to worry about figuring those areas, since it will mean having extra paint in case of spillage, miscalculations and retouching.
- TRIM & DOORS
Use the same formula for doors but measure the perimeter of the window and other trim areas and add the two sets of measurements to determine the total.
- ESTIMATING VARIOUS SURFACE SHAPES
Aside from the straightforward squares and rectangles usually encountered you may run into other odd shapes -
- Triangle: Multiply one-half the altitude using feet, by the base measurement using feet.
- Circle: Multiply the radius by itself, then multiply the result by 3.1416.
- Cylinder: Use the circle formula to determine the area of both ends, then multiply the circumference by the height to determine the side area. Add the square feet of both ends to the side surface for the total.
- Cone: Determine the surface area of the base by using the circle area formula.
The side area is estimated by multiplying the circumference of the base by one half the height of the slanted surface. Add the square footage of the base and side surface.
To calculate the exterior of a structure, multiply the total distance around the house by its average height (distance from the foundation to the eaves for a flat roof; add 2 feet for pitched roofs). This will give you the number of square feet which is divided by the square foot coverage of the coating.
Once you know the square footage of the area to be covered you must also determine if you will need one or two coats of paint. It is generally recommended to use two coats when - 1. Covering a dark color with a lighter one. 2. Painting over porous masonry surfaces such as stucco. It is always better to overestimate the amount of paint that you need, rather than come up short in the middle of a job .
Paint sitting on a shelf is an unfinished product. All the fine properties and qualities contained in a can of paint are useless until they are applied to a surface. There they undergo the chemical and physical changes that will be of benefit to the user. Hence, the application of a coating is of great importance.
The key to proper paint application is the paint applicator and how it is used. There are two types of applicator: Manual (rollers , brushes, pads) and Automatic (sprays, coaters).
Just as selecting the right type and quality of paint is important for the durability and esthetics of the surface being painted , so the type and quality of the tools used to apply the coating is important. The tools of any craft must be carefully selected, a fine professional paint brush requires special construction and materials and is relatively costly . The wise painter has different brushes for the various tasks that he has to perform.
Brushes are made from three basic types of material.
Bristle (Natural Hog Bristle): Being a product of nature the quality and type of bristle varies depending on geographical location and breeds of hogs they come from. Bristle brushes afford excellent performance with varnishes, shellacs and glossy solvent-thinned paints. Professionals are of the opinion that these types of brushes put on the smoothest finishes. However, bristle wears out quickly and requires extra tender loving care. This type of brush is not recommended for latex or water-based coatings since the water softens the bristle, causing it to flare out and lose its shape.
Nylon: This was the first synthetic brushing material and offered a solution to the weaknesses of bristle in latex paints. Even so, over long periods, especially on hot days, nylon will soften considerably. Nylon is not as good in coatings containing alcohol such as shellacs, or ketone solvents -lacquers. Perhaps nylons most beneficial property is its resistance to abrasion.
Polyester: This is the best general, all purpose type of brush there is. The material is unaffected by all paints and when properly formulated, applies a finish equal to bristle. A decided advantage of polyester is that a painter can maintain the same "feel" (handling characteristics) with all paints.
There are many styles of brushes available. Their differences are reflected in the shape and dimensions (width, thickness and length) of the brushing material. The following are some of the more popular styles:
Wall Brushes: These are basic painting brushes used to paint large areas. They most often have a beavertail style handle and come in sizes from 3" to 4". They are designed specifically for production and not for precision.
Varnish and Enamel Brushes: Similar to wall brushes, but somewhat thinner, they have a chisel tip and are often used for finer, smoother surfaces. Sizes range from 2" to 4".
Flatting Brushes: Dutch flatting brushes are the largest (4" to 6") and thickest brushes available. They have a very large paint capacity and are available with both flat and chisel tip. These brushes will paint a large area quickly but offer little, if any, precision.
Sash Brushes: There are two popular types of sash brush -Flat Sash which looks like a varnish or enamel brush but is distinguished by a long, thin handle, and minimal thickness. It can be used effectively for cut-in and trim work as well as painting small areas. Popular sizes range from Biz" to 3". - Angular Sash is distinguished from the flat sash in that the brushing material is built diagonally. This design allows the user to approach the surface from an angle for better control of the paint. The Oval Sash Brush is not as common as the flat or angular version. Usually W' to 1lh" wide, its bristles are built in an oval and it is used as a touch-up or specialty brush.
PAINT ROLLER COVERS
Where the paint brush requires a skilled hand, the paint roller is much more forgiving. Since the primary results are built into the roller cover itself, the selection of the proper cover for the surface to be painted, is essential.
Lambs wool: Lambs wool is a tanned sheepskin and varies from hide to hide. Proper selection based on density, curl, texture, quality and nap length, is vital to producing a consistent product. This is the material of choice for thin solvent-based paints, especially aluminum, metallic and other specialty coatings such as epoxies, polyesters and polyurethanes. Lambs wool performs poorly in latex because it tends to mat down and will be degraded by latex due to the alkaline characteristics of the paint. (alkali is used to remove the hair prior to tanning the hide.)
Synthetics: Synthetic nap fibers are made from polyester, nylon and acrylic among others. Properly formulated these rollers can make superb painting tools. Quality varies from manufacturer to manufacturer. Just as with brushes it is good to know the quality brands. Synthetic fiber rollers are the only ones suitable for latex paints. They can be used in most alkyd or solvent-based paints as well, but not with specialty coatings such as epoxies, polyesters, etc.
SELECTING ROLLER COVERS
The following are characteristics of professional roller covers.
Beveling: The ends of the cover should be precisely trimmed at an angle (beveled) so that trail marks are reduced and the results are smoother and more uniform.
End Gluing: If the ends of the core have a shiny finish, this means they have been sealed with an adhesive to increase durability. Since the ends receive the most abuse, this extra protection prolongs the life of the cover.
Finishing: The cover should be well combed out, all fibers trimmed to the same length and oriented in the same direction. If a few fibers are longer than others "pick marks" can appear in the paint film. A finished cover will look more uniform and the seams barely perceptible.
Core: A baked phenolic impregnated fiberboard core is the best and most durable. Plastic will soften easily in strong paint solvents.
Nap Length: The rule of thumb is - the smoother the surface the shorter the nap length. Many professional painters use too long a nap length for the surface in order to carry more paint and get the job done faster. This usually results in "orange peel", rough surface and poor coverage.
Note: Make sure you follow the manufacturers recommendation . Some covers are only recommended for flat paints. If an enamel or gloss is used, excess tinting may result.
Paint pads are generally not used by professional painters. They have the same restrictions on paint types as do nylon brushes. They can be used for a short time in materials containing solvents but will eventually deteriorate. Pads are suitable for all surfaces except those that are extra rough.
Common types of spray application include; air, airless, air-assisted airless and rotary spray; while High-velocity, low pressure (HVLP) is a newer form gaining popularity.
Air spray guns use air to atomize paint into particles that are applied to a substrate. The spray gun is made up of several systems. One draws the fluid into the gun using pressure . A second delivers the pressurized air through the gun to the spray cap. The two systems join at the cap where the paint is sprayed under pressure through the cap and atomized to form a spray pattern. When electrostatic charging is desired, a third system sends an electrified current to the spray cap giving the atomized paint an electrostatically negative charge .
Fluid Delivery: Paint enters the gun at pressures ranging from 8 to 30 psi. As the gun trigger is pulled the fluid needle is pulled back, allowing fluid to exit the gun and be atomized by the air coming from the air-make-up system. Increase the pressure by pulling the handle and more paint is applied release the handle and the amount decreases. If the fluid pressure is increased too much the gun cannot be atomized properly and poor paint application will result.
Setting Up to Spray: Before using any type of spray equipment you first have to determine the viscosity and temperature at which the paint will be applied . This means that weather and surface conditions need to be monitored closely before application. Spray application settings depend on the temperature and viscosity of the paint. Use a viscosity meter to determine this. Less pressure is required for a lower viscosity, more for a higher level. Once the levels are determined, the proper fluid delivery needs to be decided. The best way to do this is to turn off the air pressure, hold the gun horizontally to the ground and pull the trigger. Adjust the fluid pressure until a stream of paint comes out that is 8 to 12 inches long. Once that is done all that is left is to determine the air needed to achieve proper atomization. Run a test at 45 psi, spray an even pass on a piece of cardboard, then adjust the psi in increments of 5 and retest. Compare the sizes of the particles on the cardboard to see which level gives you the smallest ones. Now the spray gun is set.
Before you start, make sure that your air supply and your equipment is free of oils, moisture and other contaminates. Many times the cause of a poor paint finish is contaminated air that is being supplied to the gun.
Electrostatic Spray: Introduced in the 1940s these types of spray guns set up a negative charge in the atomized paint so that any positively charged surface will attract and adhere the paint. This method reduces over spray and increases transfer efficiency. Coatings applied in this fashion require careful selection of their solvent base so that the correct charge can be acquired. Waterborne or latex paints cannot be used in this type of system since the high conductivity of water is likely to short out the spray gun. Waterborne paints require systems that can be isolated and charged as a whole .
Now that you know what paint and what equipment you're going to use, time to get down to painting right? Wrong. Before any of the fun can start you have to prepare the surfaces so that they can be coated and stay that way for a long time.