Guide: How to Choose the Right Industrial Primer
“What’s the best metal primer?” This may not be the most popular answer, but …it depends. The ideal primer for one job (or set of conditions) may be completely different for another job. It depends on a few key factors:
Questions to Ask When Choosing an Industrial Primer
Here are some key questions you should ask:
- Surface Compatibility: What type of surface do I have? The ideal product will differ drastically depending on which surface you’re applying the primer to.
- Corrosion Resistance: Is there rust already on the surface? Is there potential for rust in the future? Does the primer offer protection against corrosion, especially for metal surfaces?
- Durability/Chemical Resistance: Do I need exterior durability? Will there be exposure chemicals?
- Drying Time: Does it matter how long it takes to dry or cure before applying the topcoat or before use? Do I need the primer to dry as quickly as possible so I can increase production, or is long-term durability a bigger priority?
- Environmental & Safety Regulations: Are there environmental requirements in my area? Do I need to meet federal, state, city, or specific requirements of my company? Is it compliant with local environmental regulations?
- Primer and Topcoat in One: Do I need a primer and topcoat in one? Am I willing to sacrifice the benefits of a multi-product coating system? Can this product be applied directly to a bare metal surface as a finish coat, or does it need to be top coated?
- Cost Efficiency: What is my budget? Is my biggest concern cost per gallon or cost per job?
Let’s discuss these factors in more detail.
1. Surface Compatibility:
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- Ferrous Metals: Ferrous metals contain iron, such as stainless steel, carbon steel, and wrought iron. Common items that may be primed include structural steel, pipes, hand railings, etc. After proper cleaning, these surfaces may be coated with a wide variety of primers from solvent-based and water-based, to epoxy primers.
An exception to this would be galvanized steel, which has a zinc coating to prevent rust and corrosion. Solvent-based primers don’t stick to galvanized steel because of a chemical reaction called saponification. For this reason, alkyd-based primers are not to be applied on galvanized. Instead, a non-alkyd primer is recommended. Here are examples of primers we would recommend: Waterborne Acrylic Primer 2700 or Flexi-Coat 3601 Primer
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- Non-Ferrous Metals: Non-Ferrous metals do not contain iron. They are generally lighter, and more malleable such as aluminum, tin, copper, zinc, etc. Water-based primers are recommended for optimal adhesion. We’d recommend: Waterborne Acrylic Primer 2700 or Flexi-Coat 3601 Primer
- Wood and Concrete: These can be coated with a wide variety of primers from solvent-based and water-based, to epoxy primers.
- Non-Ferrous Metals: Non-Ferrous metals do not contain iron. They are generally lighter, and more malleable such as aluminum, tin, copper, zinc, etc. Water-based primers are recommended for optimal adhesion. We’d recommend: Waterborne Acrylic Primer 2700 or Flexi-Coat 3601 Primer
2. Corrosion Resistance:
There are various levels of corrosion resistance available on the market.
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- Rust Inhibition: For jobs that don’t require optimal rust elimination, a light sanding and a rust-inhibiting primer (containing corrosion-inhibiting pigments) may suffice. A suitable primer for this level of rust prevention would be Flexi-Coat 3601 Primer.
- Rust Blocking: For trapping rust beneath a primer coat, use a rust-blocking primer. This type of primer traps rust beneath the coating, preventing it from growing or bleeding through a top coat.
- Rust Converter: For optimal rust elimination, use a rust-converting primer that contains zinc, which is “self-sacrificing.”
3. Durability/Chemical Resistance:
The most important factors to consider here are the environmental and chemical conditions the primer is going to face:
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- For temporary protective coatings during fabrication and transportation, a basic shop coat or universal primer may be sufficient.
- For extreme conditions such as humidity, saltwater, exposure to oil/chemicals, and UV rays, a higher level of protection is needed. We would recommend an epoxy primer top coated with a urethane or alkyd enamel. For general durability, we’d recommend a phenolic primer or a 100% pure acrylic water-based primer.
4. Drying Time:
Nobody wants to wait for paint to dry. However, being aware of the optimal dry-time for your job is a critical factor in determining how successful the finished product will be. You need to ask yourself two questions:
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- Do I need the primer to dry as quickly as possible in order to increase production?
- Or, is long-term durability the biggest priority?
In a perfect world you want to answer yes to both, but ONE is going to have to be the deciding factor. That said, plenty of our fast-dry primers provide excellent durability. Examples include universal primer, phenolic primer, and water-based primer.
In terms of just alkyds, slower dry time implies longer oil length which in turn solvates aliphatic materials (grease and grime) better. In other words, a slower-drying alkyd will fare better over marginally prepared surfaces. That said, PR Series primers are fast-dry primers made with slow-dry alkyds. However, all surfaces should be prepared well for the primer to adhere properly and give you the best results.
5. Environmental & Safety Considerations:
Every company is going to face some type of environmental and safety regulations, which can vary depending on federal, state, and local requirements. Wherever you fit within this spectrum, we will work with you to develop a compliant system tailored to your specific needs. We also offer an environmental report to monitor your VOC and HAPs levels, ensuring your reporting process is seamless.
6. Primer and Topcoat in One:
The term “Paint and Primer in One” has become a buzzword in the industry. Who wouldn’t want to buy one product and call the job done? However, as you’ve seen, many factors influence the choice of both primer and topcoat. The main consideration is, can a product be applied directly to a bare metal surface as a finish coat?
There are a handful of cases in which a primer coat can also serve as a finish coat (or topcoat). An example of this would be a wrought iron fence. Our Universal Primer in black protects the surface, while also providing a flat black finish that can withstand everyday elements. Generally, however, you’re going to want a separate primer and topcoat to customize the needs of your job and get the optimal protection and finish.
7. Cost Efficiency:
It’s easy to think of cost (price per gallon) as the main (or only) factor. No one wants to spend more if they don’t have to! There are a lot of ways to look at cost, however, both long-term and short-term. In addition to considering price per gallon, you may want to consider the overall cost of the job. What is the coverage per square foot? What are the volume solids of the coating? Are you really saving money if you buy the cheapest primer per gallon, but you’re having to use twice as much to finish the job?
You may also want to consider other factors like durability or chemical resistance down the road. If you must repaint in a year due to poor resistance to the elements, are you really saving in the long-term? Our team is happy to help you produce a system that meets your financial constraints while also giving you the coverage and performance you need. Ultimately, you want to pay just enough for what you need, without paying more for features and add-ons that aren’t relevant to your job.
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.