Paint

What is the purpose of paint? What effect will cold temperatures have on paint? What does the paint consist of? What will happen if the paint film is exposed to cold temperatures or moisture like dew or rain? What does each basic ingredient of paint do? What makes an interior paint washable? What types of pigment are there? What makes paint hide well? What types of binders (vehicles) are there in paint? What factors control the price of a paint coating? Why use so many different binders in paint? What is the best product to use, latex or oil? What kind of thinner is most commonly used in paint? How important is surface preparation? What makes a flat, satin, semi-gloss or gloss finish? Will a fresh coat of paint hold down an old peeling coat of paint? Why do flat products have a higher pigment-to-binder ratio? Will one thick coat of paint do as good a job as several thinner coats, as recommended on most paint labels? Does gloss have an effect on how durable a product is? What makes paint wash well? How does paint dry? Does paint have a shelf life? Can lacquer thinner or some other strong solvent be used to speed up paint dry time? Can oil or latex paint freeze?   What is the purpose of paint? 1. Protection 2. Beautification What does paint consist of? 1. Pigment 2. Binder 3. Thinner 4. Additives What does each basic ingredient of paint do? PIGMENT: 1. Provides color. 2. Provides coverage. 3. Protects binder from weathering (i.e. UVA) 4. Some types of pigment control gloss. BINDER: 1. Holds pigment together when in dry film form. 2. Acts as a 'vehicle' that carries pigment when applied. 3. Type determines durability of end product. 4. Provides adhesion to the surface to which it is applied. THINNER: 1. Combines with pigment and binder to control consistency. 2. Plays a roll in film drying. ADDITIVES: 1. Help control application properties (brush, roll, spray, etc.) 2. Help some product formulations dry 3. Aid in pigment dispersion in manufacturing. 4. Aid in pigment dispersion when adding liquid colorant. 5. Determine various film formation properties. What types of pigment are there? Basically two major categories: 1. Hiding: White (titanium dioxide), red, yellow, black, brown, blue, organic and oxide colors. 2. Non-hiding: Talc, clay, calcium carbonate and silica. What types of binders (vehicles) are there in paint? There are many forms but the most common in trade paints are: 1. Linseed oil. 2. Alkyd. 3. Polyurethane. 4. Acrylic. 5. PVA. Why use so many different binders in paint? Each binder is unique in providing different benefits and can be used alone or blended with other binders to compliment each other. 1. Linseed oil is used in exterior applications only and creates a flexible oil film that aids in preserving weathered wood. 2. Alkyd is used in both interior and exterior paint. Alkyd resin is very durable and forms a hard film commonly used for heavy duty applications. 3. Polyurethane has two common uses: one is used on automotive coatings, the other is used for products that come in contact with concrete (household and industrial use). 4. Acrylic resin in trade coatings is a waterborne latex. Acrylic is used almost exclusively for exterior paint coatings. Acrylic paint is a very flexible and weather-resistant paint for exterior use. There are oil base acrylics used in the automotive industry, but those should not be confused with acrylic house paints. 5. PVA is short for poly-vinyl Acetate. This is also a waterborne resin used mainly in interior paints. PVA can be used in exterior paints either by itself, or in combination with acrylic. Exterior moisture resistance and weathering of PVA will not be as good as acrylic. What kind of thinner is most commonly used in paint? 1. Mineral spirits in most oil formulations. 2. VM&P naphtha in some spraying enamels. 3. Water in latex formulations. 4. Lacquer thinner used in lacquer varnishes. What makes a flat, satin, semi-gloss or gloss finish? 1. Flat usually has a 70% pigment to 30% binder ratio. 2. Gloss usually has a 20% pigment to 80% binder ratio. 3. Satin and semi-gloss will normally fall somewhere in the middle. Why do flat products have a higher pigment-to-binder ratio? The higher the pigment 'load' occupies or fills more of the binder. This saturation of binder allows the pigment to be present at the exposed surface. The dry paint film on the surface causes the light falling on it to scatter, so as to be substantially free from gloss or sheen. Does gloss have an effect on how durable a products is? Yes, flat finishes as a general rule us 'filler pigments' or 'extender' to lower the gloss. The extender pigments are usually soft, which reduces the scrubability, durability or weather resistance of a product. How does paint dry? 1. Evaporation of solvent - lacquers. 2. Oxidation and polymerization - linseed oils. 3. Evaporation of water and fusion - latex paints. 4. Chemically catalyzed (drier, catalyst) - oils, epoxy, etc. Can lacquer thinner or some other strong solvent be used to speed up paint dry time? In most cases, not. If thinning is needed, use the thinner recommended on the label. If strong solvent is added, uneven gloss, wrinkling, and dissolving of previous coatings are only a few of many problems that can be caused. All thinner must evaporate from a coating before a film can begin to cure. Solvent is normally added to change consistency for different application methods. What effect will cold temperatures have on paint? 1. Oil base products can have the dry time slowed down dramatically. 2. Latex paint can have film formation interrupted before it has totally formed. What will happen if the paint film is exposed to cold temperatures or moisture like dew or rain? Many different things can happen. Most of the time there may be no visible sign of a problem, but in almost all cases there will be some kind of long term affect, reducing the life of the paint job. What makes an interior paint washable? 1. The more gloss a finish has, the less dirt will adhere to it. 2. The more gloss a finish has, it will most often have a harder and more washable finish, and dirt will wash off easier. 3. Low gloss or flat finishes need a very good quality resin (binder) to be washable. Lower quality coatings do not wash as well. What makes paint hide well? 1. Hiding pigment concentration is the most important. 2. How well the product flows out when applied. 3. The quality of the tool used to apply the coating (brush, roller cover, spray equipment, etc.). 4. Proper surface preparation is an important variable in making a coating hide well. If a surface is rough, paint will settle into the 'valleys' of the surface, leaving the 'peaks' with an insufficient amount of coating to provide coverage or protection. What factors control the price of a paint coating? 1. Amount of hiding pigment vs. filler pigment. 2. Quality and quantity of resin (binder) used. 3. Special formulations for specific performance applications. What is the best product to use, latex or oil? Keep in mind, many painting projects are unique and each may require a specialty finish or surface preparation. With today's advancement in latex technology, there should be a latex paint formulation for almost any application. There are many situations that require an oil base or specialty product. FOR EXAMPLE: A weathered barn or outbuilding may have very little paint left and more appropriate in this application. Oil base products generally will tolerate small amounts of dirt on a surface better than latex. Make sure to read labels for specific product information. LATEX ADVANTAGES DISADVANTAGES Fast dry. Shrinks more when drying, creating more surface stress. Better fade resistance. More temperature sensitive. More chalk-resistant. Less adhesion to chalk and dirt. Breathes; less blistering. Can stain with water-soluable contamination. Retains flexibility longer. Softer, normally not used in high traffic areas. Tolerant on alkaline surfaces like masonry.   Will not yellow.   Resists mildew better.   Clean-up with water.   Good on galvanized metal.   OIL ADVANTAGES DISADVANTAGES Less shrinkage. Turns brittle with age. Low temperatures have less affect. Slower dry than latex. More durable in high traffic areas. Colors fade faster. Seals stains better. Chalks faster than latex. Holds rust better on steel. Tight film blisters faster (won't breathe). Better adhesion on dirty or chalky surfaces. Yellows with age.   Peels on galvanized metal. How important is surface preparation? Surface preparation is the single MOST IMPORTANT variable in determining the service life of any coating. Proper surface preparation insures maximum adhesion to any surface. Even the best paint available today will not adhere to an excessively dirty or greasy surface, or if moisture and contaminates penetrate behind the paint film. Proper surface preparation will decrease the chance of contamination, discoloration, inconsistent gloss or improper film formation of a finish coat. Will a fresh coat of paint hold down an old peeling coat of paint? No.  One common belief in the consumer market is that paint is glue and will hold down a previous coat. If anything, it may put stress on an old dry brittle coat, causing it to peel faster. Check to see if there is an old coat of paint under the new finish when you are presented with a peeling problem. Will one thick coat of paint do as good of a job as several thinner coats, as recommended on most paint labels? No, one thick coat of paint can cause a variety of problems. When paint is applied too thick, mud cracking, wrinkling, slow dry time, surface skinning, and stress inside the paint film can cause premature failure. These are just a few of the problems that will likely occur. Most coatings are designed to be applied at three to six 'mils' wet paint thickness per coat. As a reference, plastic is sold in 'mil' thickness. What makes paint wash well? 1. Hiding pigment concentration is the most important. 2. How well the product flows out when applied. 3. The quality of the tool used to apply the coating (brush, roller, spray, etc.). Does paint have a shelf life? Yes, each paint has some type of shelf life, it can get old! There are various reasons paint can get old. Paint in a spray can is quite thin, causing settling much quicker than gallons or quarts. The shelf life on spray cans is about 1-2 years. Paint in fives, gallons and quarts, or most other containers, can expect a shelf life of 2-5 years. The older the paint, the more likely you will encounter problems. Can oil or latex paint freeze? Latex paint cannot tolerate a freeze without some negative consequence. In many cases, it may not be noticeable in the can or during application; however, long-term durability will suffer relative to how hard the paint freezes. Oil paint, in most cases, can take almost any temperature. There are some formulations that can 'shock' if exposed to extreme cold. A paint that has been 'shocked' will have the different ingredients (oil, resin, pigment, solvent and additives) separate. Once the different ingredients have separated, they are very difficult to remix. As a general rule, keep all paint in a freeze-protected area. Thanks to Van Sickle Paints for making this page available to us.