To clarify some of the terms used in describing the many types of automobile and truck paints, the following is a glossary of paint terms that apply:
Primer
Primer is the necessary base for any paint job. It binds the paint to the metal, wood, fiberglass or previously painted substrate and provides a smooth and even base for the final finish. There are many different primers each with a different specific purpose depending on the type of finish being used over it and the substrate it is covering. It must be carefully chosen depending on the application. Always used regardless of finish.
Nitrocellulose Lacquer
Nitrocellulose lacquer is based on wood or cotton fiber dissolved by acids to create a resin combined with color pigment and solvents. When applied in multiple coats and sanded out between them, after a lot of hard work, it is well known for its deep and beautiful finish. Very rarely used today except on 100% authentic restorations.
Acrylic Lacquer:
Acrylic Lacquer is made of synthetic resins, pigment and solvents. Like Nitrocellulose Lacquer, it also requires a lot of hard work but when done properly, is beautiful. Very rarely used today except on 100% authentic restorations.
Enamel
Enamels or “oil-based enamels” are based in linseed or other drying oils along with pigments and mineral spirits or turpentine as a solvent. They tend to be thicker and harder than lacquer especially when baked but do not respond well to final sanding and rubbing out. Rarely used today.
Alkyd Enamel
Alkyd Enamels use a synthetic resin base, pigment and mineral spirit solvents. Like oil enamels, they tougher than lacquer but are generally not sanded and rubbed out. Rarely used today.
Acrylic Enamels
Acrylic Enamels are made with acrylic resin and have alcohol solvents. They are often used with an activator for dramatically increased durability. Still used today. Very dangerous without proper breathing apparatus!
Single Stage Urethanes
Also sometimes referred to as “Urethane Enamels”, Urethanes are modern two-component or “2K” formulations requiring an activator. The activator is usually mixed in just before use in a 4:1 or 3:1 ratio of paint to activator and has a window of 1 to several hours before hardening completely. They do not air dry but chemically harden with the activator. They provide a full gloss, do not require a clear coat, can be sanded and rubbed out like lacquer and are extremely durable, chip and UV resistant. Used in many re-paints today as well as fleet truck and aircraft use. Very dangerous without proper breathing apparatus!
Two Stage Urethanes
Also two-component or “2K” formulations like the Single Stage coatings, they also require mixing with an activator. The Base coat or 1st stage is strictly the color coat and has no gloss or protective properties and must be top coated with the Urethane Clear Coat or 2nd stage which provides a high gloss, can be sanded and rubbed out like lacquer and are extremely durable, chip and UV resistant. Used in some factory paint finishes and most repaints today. Very dangerous without proper breathing apparatus!
Water-Based/Waterborne
These are also 2 stage systems but have water-based, base color coats which have a very low toxicity level or “Low VOC’s”. The base color coats have no gloss no protective qualities. They must be topcoated with a Urethane Clear Coat or 2nd stage which provides a high gloss, can be sanded and rubbed out like lacquer and are extremely durable, chip and UV resistant. Used in most factory finishes and many repaints today, this appears to be the direction of future automotive painting. These systems require a drastically different application technique.
VOC’s
This is a popular acronym for Volitile Organic Compounds which are the powerful solvents derived from petroleum sources. Found in most solvent based finishes, they are considered to be hazardous to health and the environment.