There are two different types of paints available, acrylic latex paint and oil-based paint. Latex paint is made with water as well as an acrylic resin binder, while oil-based paint uses an alkyd resin and hydrocarbon-based solvent. Ultimately the pigments in both types of paint determine the coverage and the color or the finish. The more pigment, the better hiding properties there are.
The most important pigment in terms of paints is titanium dioxide, however it is costly. Many paint manufacturers substitute it for clay and silica but they do not hold up as well. Fillers are also added to paint products in order to enhance the performance of paints. This makes it extremely important to read the label of paint cans and determine whether price is the most important factor when choosing between oil and latex paint.
Latex paint was first made in the 1940s in Canada. The highest quality latex paint is called 100% acrylic latex, which includes various binders and pigments. The paint itself needs to be shook up or stirred in a store in order to mix the heavier parts of it throughout the water. Acrylic itself means synthetic latex. Ultimately latex paint only uses one binder, an elastomer, meaning that the paint has a surface that is elastic. After latex paint is applied to a surface it remains flexible meaning that it will expand or contract. It is also porous and keeps moisture from escaping from the paint surface entirely.
The surface of today’s latex paint is durable and in many ways superior to that of an oil-based paint. It resists scratches and scuffs well and provides a great adhesive property to the surface that is being painted. It also dries faster than oil-based paint and is much easier to clean with soap and water. It does not cause cracking or peeling as often as oil-based paints. Also, it doesn’t have as strong of an odor as oil-based paint, which means less harm to the environment. It also is not flammable. Most importantly, latex paint doesn’t yellow overtime, which means more money in a homeowner or business owner’s pockets.
However, there are some disadvantages to latex paint. First, it isn’t suitable for painting over steel without a primer. It also swells to the grain of wood, which makes sanding in between costs a necessity. This also makes a primer important as well. Latex paint does not adhere to chalky or dirty walls. It also is more sensitive to temperature changes. It has a soft film to it and takes longer to cure than oil-based paint, which means it can be damaged more easily until it is fully cured.
Oil-based paint was first made with linseed oil as its binder. In order to thin the paint, you will need either turpentine or mineral spirits to dilute it. For many years oil-based paints were the first choice for painters, but with the improvement of latex paint and many states that have restrictions against oil-based, it no longer is as popular as it once was. The restrictions occurred because the paint thinner needed in order to clean brushes or spills needs to be disposed in a special way and cannot be placed with garbage or with other trash.
Many opt for oil-based paint because it has a durable and hard finish that resists against any abrasions or scratches. The finish is so hard that it cannot be painted directly over latex paint because the surface is flexible which will cause it to crack and flake when temperature changes. Latex paint expands and contracts with temperature changes. This can also happen when layer after layer of oil-based paint is used because the surface gets so hard that it stops adhering well and cracks.
Some advantages to oil-based paint are that it goes on smoother, although it does have a longer drying time. Some of these paints need to dry for up to three days. This paint has a hard surface, which resists scratches and scruffs well. It also provides a more smooth finish than that of latex paints. They are also easy to wash because the surface is harder. Oil-based paints also hide wall imperfections better than latex because they are a thicker consistency. Oil based paint has a less refractive index which means it looks more deep and warm than that of a thin latex type paint. The texture overall will feel smoother.
Some disadvantages to oil-based paint are that you will have to touch up often. Also, this type of paint tends to yellow over time. It also doesn’t resist mildew overtime. Also, many states are passing laws against their use because they give off volatile organic compounds gasses when used. They also require mandatory ventilation when using them. Oil-based paint also tends to bubble during the painting process, which means it’s important to cure each layer before applying subsequent coats in between. Unlike latex paint, oil-based paint doesn’t breath, which means it tends to peels.
Both paints do not cure the same way, in fact oil-based paint doesn’t stop curing ever. As it ages, it continues to oxidize becoming more brittle, which makes it more prone to peeling and cracking overtime. Latex paint will cure in just two weeks and is rubbery with a breathable surface which allows moisture to evaporate.
Determining What Type of Paint is on a Wall
If you’re painting over existing paint, you must determine what type of paint you’re dealing with. Take a cotton ball soaked with nail polish remover or rubbing alcohol and rub it on the wall. If the paint comes off, the paint is latex. If it is unaffected then it is oil-based paint.
If the paint on the wall is oil-based, you will need to prepare the wall in order to partially remove the smooth, hard surface. Lightly sand with a 100 grit piece of sand paper wrapped over wood. You need to rough up the surface in order to change the smooth oil surface into a surface that has some bite. Next wash the walls in order to remove any grease, dirt or dust. Apply a primer to the wall. Allow it to dry for many days and then apply your latex paint. You will need to apply at least two coats for the best coverage.