Metallic Coatings Application | Iridescent Coatings Application | Pacific Southwest Coatings

Application of metallic and iridescent coatings

architectural performance coatings application guide

The architectural application of metallic and iridescent finishes in a field application is a multi-step process requiring a well thought out procedure, superior application skills, ultra violet resistant primers, specialty application equipment, consistent air supply and an expectation of a production rate that is a fraction of the rate of most architectural coating products. Metallic and iridescent finishes are translucent or clear resin systems with 3-dimensional pigments that layout in a pattern that is dependent on the application technique employed by the applicator, the consistency of the air supply and steady flow of pigment through the gun.

Geometry of Substrate and Mock-Ups

Before the application of any coatings, consider the geometry of the substrate. Difficult shapes, angles and hard to reach areas that pose a problem for the applicator to keep the gun perpendicular to the surface must be considered. A plan should be developed to work with the geometry and a mock-up is recommended so all parties have the same level of expectation for appearance. Consideration should also be given to eliminate the coating of areas with metallics or iridescent finishes that will not be properly lit to provide the desired appearance.

Primers and Base Coats

Metallic and iridescent coatings are translucent and in exterior conditions ultraviolet light will penetrate through the coating to the primer. It is essential that the primer or the base coat be able to hold up to ultra-violet light. DTM 1300, DTM 1400 and DTM 3000 are all designed to resist long-term exposure to ultraviolet light. Conventional epoxies and alkyds should never be used under metallic and iridescent coatings unless an ultra-violet blocking base coat is used as an intermediate coat. The primer or the base coat should be applied over the entire substrate to be coated to achieve a consistent background color for the finish coats. The color of the primer or base coat should be selected to enhance the finish coat as the finish coat is translucent. A gray primer is an excellent background for a silver metallic finish.

Air Supply

The constant flow of air in terms of quantity and pressure is essential for the successful application of metallics and iridescent coatings. The metallic flakes (aluminum) and iridescent chips (mica) layout in the resin system dependent on the way the coating is applied to the substrate. Inadequate air volume or inconsistent air pressure will result in the misalignment of the pattern resulting in a splotchy appearance.

Application Equipment

In the automotive refinish market where most manual applied metallics and iridescent coatings are used, the gravity feed HVLP gun is the choice of applicators. The gravity feed gun delivers the metallic and iridescent pigments in an even and consistent manner as long as the cup remains primarily upright. The advantage of the gravity feed gun is that the consistency of the metallic dispersion in the application stream helps to eliminate pigment striping that can be experienced with conventional HVLP pressure pot systems and HVLP turbine sprayers. This is not to say that metallic and iridescent coatings cannot be applied effectively with a conventional HVLP pressure pot system or a HVLP turbine sprayer, but the use of such equipment can make the desired finish more difficult to attain.

Commonly used architectural airless equipment and industrial airless equipment is not recommended for the application of metallic or iridescent coatings. Standard airless equipment delivers the coating to the substrate too quickly and without the consistent flow of the metallic and iridescent pigments which will result in a stripe pattern on the surface being coated.

Some good success has been noted by applicators using air assist airless fine finish equipment. This type of equipment has proven to deliver metallic and iridescent pigments fairly evenly in the hands of an experienced and skilled applicator.

The Applicator

The most important component of a successful application of a coating system is the applicator. A skilled applicator who understands the detail and precision required to successfully apply a metallic or iridescent three dimensional coating system is more an artist than a painter. Success depends on staying in front of your work, keeping the gun perpendicular to the surface, moving into or away from the work to achieve the proper dispersion of the metallic flakes or iridescent chips in the coating film while maintaining proper orientation of the pigment.

Application of metallic and iridescent pigments is impacted by distance from the substrate. The closer the gun is to the substrate, the more the pigment will bury in the resin system resulting in a darker and sometimes deeper appearance. The further away the gun is from the substrate the more the pigment will lie on the top of the coating resulting in a brighter appearance. The same material applied by the same applicator the same day at different distances from the substrate can substantially change the color and appearance of the same gallon of metallic or iridescent coating.

Coating Process

Substrate and Surface Preparation
Carbon steel substrates should be cleaned and degreased prior to surface preparation. Substrates may be slightly corroded but all loose corrosion must be removed. Contingent on the corrosion protection required an SSPC-SP6 shop cleaning, SSPC-SP10 near white metal cleaning or an SSPC-SP3 power tool clean are the traditional levels of cleanliness recommended for commercial atmospheric areas. If an SSPC-SP3 is utilized it is highly recommended that the prepared carbon steel be treated with Precision Metal Conditioner 02150.

Aluminum substrates and anodized aluminum substrates should be abraded with a minimum 180 grit aluminum oxide abrasive paper utilizing a power tool or hand tool cleaning. It is highly recommended that the prepared aluminum be treated with Precision Metal Conditioner 02150.

Galvaneal (Paintloc type) systems should be cleaned and degreased. Cleaning can be done with Precision Metal Conditioner 02150.

Stainless steel should be cleaned and degreased and must be abraded with a power tool clean utilizing 180 grit abrasive paper. The prepared and cleaned surface should then be coated with a surface tolerant epoxy designed to be applied over stainless steel such as Amerlock 2 VOC.

Performance finish coated surfaces that are tightly adhering should be cleaned and degreased. The coating should be tested for compatibility with the Precision Coatings DTM primers and finish coats. The existing coating should be abraded with a hand or power tool cleaning utilizing 180 aluminum oxide paper.

Single component primers and finishes that are tightly adhering should be cleaned and degreased. The coating should be tested for compatibility with the Precision Coatings DTM primers and finish coats. The existing coating should be abraded with a hand or power tool cleaning utilizing 180 aluminum oxide paper.

Fluorinated polymer (Kynar, Duranar type) systems that are tightly adhering should be cleaned and degreased. New and aged surfaces should be cleaned and degreased. The existing coating should be abraded with a hand or power tool cleaning utilizing 180 aluminum oxide paper.

For recommendations on other substrates, please contact your Precision Coatings technical representative.

Primer Selection
Carbon steel commercial moderate      DTM 1300
Carbon steel corrosive environment     DTM Organic Zinc Rich Primer / DTM 1300 intermediate coat
Aluminum and anodized aluminum         DTM 1300
Galvaneal                                          DTM 1300
Performance finish                             DTM 1300
Single component                              DTM 1300
Fluorinated polymer                           DTM 1300

DTM 1300 must be lightly abraded after 72 hours of cure to be topcoated.

Finish Coat
Precision PC3 Metallic or Iridescent color

Tack Coat
The tack coat is a light coat that is applied to the surface to promote adhesion of successive coats. This coat covers the surface but does not fully wet out the substrate as the coating will have a light, uneven and transparent appearance.

Wet Coat
The first wet coat is applied over the tack coat approximately 10 to 20 minutes after the application of the tack coat. This coat wets out the surface and presents an even appearance however the coating can still appear to be transparent.

Wet Coat
The second wet coat is usually the final coat and is applied 10 to 20 minutes following the application of the first wet coat. This coat should wet out the surface, presents and even appearance and with the exception of very few colors full hide should be achieved. On special effect systems such as three, four and five stage iridescents as well as colors that need extra coats to attain full color strength successive wet coats can be applied using the 10 to 20 minute separation between applications.

Clear Coats (Optional)
Precision Coatings clear coats are not necessary due to the high performance resin systems used in the PC3 metallic, iridescent and color coats. If a clear coat is desired to add depth of image or for cutting and buffing, the clear coats can be added over the color coats by waiting twenty minutes, or allowing the initial application to cure eight hours.

PC3 must be lightly abraded after 24 hours of cure to be topcoated.

Contact numbers

Phone: 562.691.9600 OR 714.777.0300
Fax: 714.777.3586
E-Mail: support@pacificsouthwest.net

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