Latex paints can be thinned with water and are easily applied. Compared to oil-based paints, the advantages of latex paints are:
- Less odor
- Water cleanup
- Rapid drying
- Easy touchup
- Easy application, even on damp surfaces
- Better gloss and color retention (less fading) on exterior surfaces
- No yellowing on interior surfaces
- Remains more flexible and less brittle, which makes them less likely to crack and peel.
The disadvantage, especially of some lower-quality or promotional products, are poorer adhesion to blistered, peeling or chalking surfaces, and, in some cases, less-effective hiding qualities.
Latex paint films on wood allow moisture to evaporate through the film, reducing blistering.
Oil-based paints consist of a pigment in a vehicle made up of resins and thinners. When thinners evaporate, the resins form a hard coating while the pigment forms the color.
Major advantages of oil-based paint are:
- Better penetration of the surface
- Better adhesion
- Better flow and leveling
- Dry to a smoother finish with fewer brush or roller marks.
The disadvantages of oil-based paints are the odor, cleanup with solvents or thinners and longer drying time. Also, oil-based paints cannot be applied to moist surfaces.
Interior Paints and Enamels
Interior paints are available in flat (no shine), satin, semigloss and gloss (high shine).
Enamels provide a high-gloss washable finish for hard-wear areas or for rooms such as the bath and kitchen that require a high resistance to moisture, dirt and grease. Today, companies not only sell high-gloss, but eggshell or even flat enamels. Interior paints are sold in various formulations-oil based, alkyd based or synthetic based, latex, etc.
Interior paints are sold in various formulations-oil based, alkyd based or synthetic based, latex, etc.
Flat paints usually have an alkyd- base that thins with turpentine or mineral spirits, or a latex base that thins with water. Latex paints are usually vinyl or acrylic based or a combination of the two.
Alkyd flat paints may hide better with one coat than will comparable latex flats, but brushes and other tools must be washed with turpentine or a similar solvent. Latex flats spread easily, especially on porous surfaces, and seldom require a primer. Tools clean with water.
Flat wall paints are usually applied to ceilings and walls, except in kitchens and baths. Semigloss or gloss paints withstand the frequent washings required in these two rooms.
For windows, doors, wood trim and other woodwork, satin, semigloss or gloss enamels are recommended. These surfaces get more wear than walls, more fingerprints and soil. Because glossier enamels wash more readily, they are more desirable.
Semigloss latex paints serve well as finishes for wood-trim areas. They have the advantage of water cleanup.
Because enamels and gloss paints dry rapidly, more care must be exercised in application because they tend to brushmark, especially on hot, dry days. Preparation of interior surfaces is vital to good end results. Surfaces must be free from grease, dirt, mildew, chalking, etc., washed well, thoroughly rinsed with clear water and allowed to dry before repainting. Cracks and holes must be repaired and patched areas spot primed.
If surfaces are badly soiled, a trisodium-phosphate (TSP) cleaner may be necessary. However, phosphates are a recognized pollutant and TSP is more prone to deposit crystals that impair adhesion than do some other products.
When repainting glossy surfaces, sufficient cleaning materials must be used to dull surfaces, or they should be lightly sanded. An alternative to sanding is the use of a liquid cleaning/dulling solvent. High-gloss surfaces typically do not provide good adhesion for new coats of paint.
Painting over wallpaper is not recommended; the old covering should be removed. Once painted, wallpaper is extremely difficult to remove.
|The Dos and Don’ts of painting|
|Wash all grease and dirt off walls and woodwork.||Don’t expect good results on dirty surfaces.|
|Patch cracks in walls and ceilings before painting.||Don’t paint over a damp surface with oil-base paints.|
|Seal all new surfaces with a primer.||Don’t apply the second coat of paint until the first coat has dried properly.|
|Scrape off all loose paint and sand the surface to a smooth finish.||Don’t sand woodwork across the grain.|
|Stir paint thoroughly before any applications.||Don’t change cans of paint in the middle of a wall area.|
|Allow new plaster to dry before painting.||Don’t add thinner to the product unless directions call for it.|
|Properly ventilate area to be painted.|