Metal Coatings

About Metal Coatings

Metal coatings are coatings that are primarily used to protect metal from corrosion, deterioration and aging. Unprotected metal will rust with environmental exposure.

Maintenance coatings are a general purpose coating used primarily in the steel industry. Metal surfaces need constant repair in the following industries: highway and railroad structures, chemical and manufacturing plants, public utilities and other facilities that suffer from corrosion and harsh environmental conditions.

These coatings prevent deterioration in metals that corrode when two metals with different electrochemical charges are linked through a conductive path. Here are some industries that primarily utilize this type of coating: plumbing & heating pipes, fire prevention, instrument panels, mechanical automotive parts, electronics and recreational goods.

Sales Team

John Morris – Technical Sales Engineer

Dan Laguerre – Technical Sales Engineer

Robert F. Rowinski – Technical Sales Engineer

Edward E. Rochford – Technical Sales Engineer

Metal Primers (Air Dry & Bake)

There are a number of metals that don’t work well with coatings, but, do have good adhesion properties. Aluminum, white bronze, plated finishes like cadmium, chrome or steel are just a few. Therefore, each requires a primer to provide the adhesion between the raw metal and the final topcoat.

Here are some of the primers used with these types of metals: 

Clear Epoxy Primer – used as a base coat for air-dry lacquers or baked enamels. This epoxy primer can be sprayed or dipped and air dries in 5 minutes at room temperature. It provides the maximum adhesion for the final finish, however, it should not be used as the top coat because it will yellow over time.

Zinc Chromate Primer – Untreated, raw aluminum and steel are the two metals that utilize a Zinc Chromate primer the best. It provides an excellent layer beneath any coating because the metal treatment uses phosphate to activate adhesion and it prevents under-creepage of rust if the protective coating gets damaged. The topcoat must be applied before you expose the finished piece to weather.

White Primer – This coating is ideally suited for a variety of metals, plastics and wood surfaces. It adheres well because of its flexible properties. White primer dries quickly, is non-yellowing and is water resistant.

Oxide Primer – A very versatile primer, Oxide primer offers excellent adhesion to cold rolled steel and comes is several colors including; Red, White, Black, Yellow & Grey. We can also custom formulate additional colors. It is durable, water resistant, it aids in preventing stains and abrasion. There are multiple processes (air-dry, force dried, baked or with application equipment) in which to apply this primer. Oxide primer is suitable for sanding, if needed.

Basic Oxide Primers

When coating metals it is essential that you prime a metal before coating it with a finish to help fight its biggest enemy, corrosion. The difference between a paint and a primer is that paint is usually created with a large amount of pigment for that last quality coat. Primer on the other hand, contains the binding elements that create better adhesion and serves as the foundation for the final coat to stick to.

Every metal has a different porosity, so using a primer that matches the surface you are protecting, is key. Primers can fill in some of the defects of the metal using epoxy or urethane based primers and although they are not beautiful to look at, their primary purpose is to coat and aid in the protection of corrosion.

Once a primer is applied, a topcoat is added with the chosen color adding another layer for additional protection from weathering and other performance requirements.

The two basic Oxide primers used in the protection of metals are red oxide and zinc oxide.

Zinc oxide primers evolved from the zinc chromate primer used in the aircraft industry in the 1940’s, they have a yellow tint and can also be found with a variety of added pigmentations

Specialized Rust Inhibiting Primers

Time and money is always a concern in the industrial building and commercial property sectors. Doing the job right the first time, saves downtime and loss of earnings if you have correctly prepared and primed your metal surfaces.

A rust-inhibiting primer is the most important preparation of a surface, substrate or material, prior to it being painted with a final finish. It creates a better adherence to the surface and alleviates stripping and re-application problems in the future.

Some surfaces that have been previously coated may not require a primer. However, new and raw metals exposed to the environment (structural steel, oil-rigs, marine equipment, etc.) should be sealed with a rust inhibiting primer to add extra protection before the final topcoat. It will provide a lasting, durable finish for years to come.

Single & 2 Component Epoxies

Single component epoxies can be used straight from the tube without any mixing required. The mixture contains the resin and an element that requires heating in order to cure completely. UV light-curing expoxies are also available in single component versions. This variety is best used for assembly line processes.

Two component epoxies are the most common because they require the user to mix a resin and a hardener. The hardener triggers the polymerization required for curing. An exothermic reaction occurs when the two are mixed, and the molecules begin to cross-link.

The two component version is somewhat stronger than single component varieties, because of their different curing characteristics. The advantage of two component epoxy is that it can achieve a handling strength in a matter of 5 minutes up to 8 hours and can solidify in 2-3 hours at room temperature alleviating the heating process and machinery. The drawback is that it needs to be mixed each time it is used.

Your choice of single component or two component epoxy will most likely depend on the specific application you need for your end result.

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