If you’re looking for the best value in a tough, durable coating you can’t beat enamel.
Enamels come in two main types, Solvent-Based or Water-Based. Water-Based and Waterborne technology has gotten a lot better in recent years, but they still don’t offer quite the same performance as a Solvent-Based Alkyd Enamel. Enamel formulations are an excellent solution for a wide variety of applications, but they aren’t the answer to every coating challenge.
What Is Enamel Paint?
Enamel paints are often described in various terms; “oil-based”, “solvent based”, “alkyd”, “water-based”, “water-borne”, “water reducible”, “modified alkyd”, and others. These are really just variations on a common theme. The main component is the resin; it’s the real guts of the product.
Let’s start with the “Oil-based”, “Solvent Based”, or “Alkyd Based” options.
Alkyds enamels are based on organic polymer resins. There are short, medium, or long-oil options that will impact the overall properties and method of application, and long-term durability.
- Resins are the binder in paint, which is the part that does the work of adhesion and overall bonding to the surface.
- Pigments (dry or liquid) provide hiding and color.
- The solvent or thinner keeps the product a liquid from the can to the surface. Once it evaporates, it leaves behind a hard coating on the surface.
- Various additives may offer unique characteristics for a specific formulation.
In water-based enamel versions, the thinner/solvent is water. After application, the water evaporates and leaves the resin, pigment, and additives bonded to the surface.
In a solvent-based alkyd enamel paint, the thinner/solvent can have many different options.
Common examples include:
- Xylene
- Toluene
- Alcohol
- Mineral spirits
- VM&P naphtha
- Various ketones like MEK or MIBK
Each one has different characteristics, so there are many to choose from when considering dry times, flash point, flammability, and solubility. Like the water, these “solvents” evaporate and leave the resin, pigment, and additives bonded to the surface.
The choice of vehicle is a direct factor in determining the dry time of the process. A faster drying solvent will evaporate faster and leave a dry film sooner. Faster drying formulations will need to be applied by a sprayer where slower drying versions can be applied by spray, brush or roller, or even hand mitt.
What about the percent of solids in the coating?
Another factor to consider is the percentage of solids in the overall coating. The percentage of solids will impact the application characteristics and overall durability of the coating.
Lower solids products may be easier to use but will leave less coating on the surface. Higher solids products may be more difficult to use but will leave more of the coating on the surface.
What about mixing oil and water? Can I get the benefits of oil-based hardness with water-based cleanup?
Yes, these are called Water-Reducible Alkyds (WRA’s). Using the solvent-based resin in a water-based vehicle can be achieved but it carries a different set of pros and cons. Factors such as shelf life, in-can stability, and dry times may help in determining if WRA’s are a good choice.
Characteristics Of Enamel Paints
Confusingly, the term “enamel” is used for a wide variety of formulations. Most people may have preconceived notions about what they think an “enamel” might be. It is very important to determine what exact kind of enamel you are speaking about and the pros and cons of each version.
Appearance
Enamels can be formulated for any sheen level. The majority of products are gloss or high gloss but there are often times when a semi-gloss or even flat is preferred. As with most products, any color can be achieved.
Application
Enamels are generally very easy to use. You do not need specialized equipment or a two-component system to get the job done. Depending on the type of enamel selected, there may be variations in how the product is properly applied. If the proper technique is used, all enamels can create a uniform, smooth finish for a variety of substrates.
Performance
Enamels are generally hard coatings. The length of the chain will determine the hardness. Typically speaking, short oil alkyds dry fast and get hard, long oil resins dry slower and stay softer longer. Once either one is fully cured, enamels will resist impact damage and abrasion but the downside is potential lack of flexibility.
Strengths & Limitations Of Enamel Paint
When you’re choosing between enamel and other types of chemistries (Epoxy, Urethane, etc.) there are several factors to consider, and note that color is not one of them!
The main points are:
Drying time
Enamels can be formulated with a wide variety of drying times. Certain things to look for are the type of resin used, short, medium, or long oil.
What is the vehicle or solvent in the formula, does it evaporate fast or slow? The majority of enamels use medium or long oil resins so they can be applied by spray, brush, roller, or even by hand mitts. However, most industrial manufacturing companies use a fast-drying, short oil enamel so they can maximize their throughput.
There is no single formula that will work for everyone. Once the preferred dry time is determined, you can decide on the desired level of durability.
Durability
Durability is generally described by continued adhesion to the surface, color/gloss retention, and protection of the substrate beneath the coating.
Several factors can contribute to the overall durability of an enamel. One factor to consider is the percentage of solids found in the formula.
The percentage of solids will indicate how much of the resin, pigment, and additives will be left behind on the surface when the solvent evaporates. Lower solids products may be easier to spray but they will leave less coating on the surface.
How much product is left on the surface can determine the overall durability of the coating. The majority of enamels offer good performance in regard to the typical factors of durability. Impact resistance, abrasion, color retention, and gloss retention are typically the areas where enamels can provide a great value for the purchase.
If there are other concerns regarding chemical resistance or UV protection, there may be a modified enamel version which may be a good fit. Improved performance can be achieved by the addition of a polyurethane hardener which adds improved UV protection as well as increased hardness, faster dry times, and better chemical resistance to the qualities of the enamel.
Environmental concerns
Since the Clean Air Act of 1999, there have been increasing concerns over the solvents used in all paints and coatings. There are federal, regional, state, county, and even city standards that may dictate the amount of volatile organic compounds (VOCs) present in the can.
Over time, there are now lower VOC and low hazardous air pollutant (HAP’s) products on the market which can be applied under any of the various restrictions. Knowing what conditions are required to comply will help you select the appropriate product.
Although water-based products are generally formulated with fewer VOCs, there are now solvent and water-based versions which can be applied in even the harshest areas of restrictions.
When To Use Enamel Paint
The use of enamel is really the starting point when selecting a product for industrial applications because of the improved performance over typical house paints. They are easy to apply and bond readily to metal, steel, concrete, and other surfaces.
Enamels are very durable and can withstand moderate to severe impact and abrasion. Weather-ability and fade resistance make it a good choice for outdoor applications where there is exposure to moderate to severe weather conditions.
When Enamel Isn’t The Best Choice
There are many applications where enamel paint is the best choice, but also times when it is not.
Flexibility of the coating
A substrate that might flex or expand could cause enamel to crack. For this reason, enamels are generally used on rigid surfaces and objects. There are modified versions of enamels (ex. Acrylic Enamels) that can improve flexibility, but during extreme conditions, a different coating must be applied.
Chemical resistance
A second reason for not choosing an enamel is chemical resistance. Although typical enamels are adequate for moderate exposure and some modified versions can withstand severe conditions, enamels are no match for epoxies when it comes to extreme chemical resistance.
Performance
The wide variety of enamels offer various levels of performance. For most applications and performance requirements, an enamel option is the smartest and most economical.
For high-performance options, a polyurethane-based coating may be a better option. Polyurethane coatings offer much greater UV protection and improved gloss and color retention. However, there may be additional emphasis on application technique (two-component vs. one-component system) and overall cost per square foot is often much greater.
Residential, Commercial & Industrial Applications
In residential applications, enamel paints have long been used for cabinets, doors, and windows. What began as a solvent-based dominant industry is generally now a water-based preference. Now it is a preference of the painter to select what they feel most comfortable with because both chemistries offer great solutions for the residential market.
In commercial applications, enamels are the workhorse paint of the projects. Solvent-based and water-based options are both used depending on the specification of the architect or engineer. Dry times, durability, and environmental concerns are typically more of a factor in commercial projects than with residential. For this reason, commercial projects may use more of the spectrum of enamel options.
Enamel coatings are still widely used in industrial applications. In less than extreme conditions, the enamel coating system is the go-to product for most manufacturers.
Enamel paint is ideal for OEM manufacturers in the oil and gas industry, agriculture, waste management, and general metal fabrication. Structural steel, heavy equipment, steel storage tanks, structures, shelving, and most equipment used outside requires the enamel coating system. Industrial maintenance is another huge industry for the enamel system. Oil field supply shops, equipment auctions, farm equipment repainting, and any other time when something needs to be repainted.
If you’re looking for paints and coatings formulated to suit a wide range of residential, commercial, and industrial applications, Anchor Paint has what you need.
Click below to browse our extensive range and select the industrial enamel paint best suited to your specific project. Or, click here to start a conversation with one of our trusted advisors who can guide you to find the perfect solution.
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