How to Select an Industrial Mixer for Highway, Road and Traffic Paint Formulations


Mixer Selection for Highway and Road Paint Formulations

Marking paints for highways, roads and parking lots are produced in a wide variety of formulations that must meet increasingly strenuous DOT requirements for volatile organic compounds (VOC’s), dry-times and durability. Furthermore, these products must be suitable for differing regional temperature variations, humidity differences and other application specific conditions. When researching leading manufacturers’ instructions for utilizing these products one critical requirement is common to all of them prior to application: Thorough mixing!

Traffic and road paint formulations vary relative to density (or specific gravity), viscosity and ingredients similar to paint products used in other industries. Generally, these include water-borne (latex), plural-component (often epoxy and catalyst) and thermoplastic products. Common containers are intermediate bulk containers (also called IBC totes), 55-gallon drums and 5-gallon pails. Regardless of formulation type the important properties from a mixer selection standpoint are the density of the materials that must be blended including high solids content, the potential addition of reflective glass beads, the viscosity of the formulation and the size and geometry of the container in which effective mixing must be achieved.

Densities on traffic paint data sheets are commonly shown as weight per gallon in lbs./gallon. They may also be expressed as specific gravity, the ratio of the product density to that of water. For example, a paint with specific gravity of 1.2 is 1.2 x 8.35 (lbs. /gallon for water) = 10.0 lbs. / gallon. Viscosity may be expressed in centipoise or in alternative units of measure such as KU (krebs units). Together, these characteristics with consideration for the container size and shape determine the mixer power rating, torque, rpm range and impeller type and size for successful solids suspension and homogeneous product ready for application.

The following paragraphs discuss these important products from the perspective of industrial mixer selection. Optimal mixing results are based on the formulations’ material properties and the standard containers in which they are sold and distributed.

Highway and Road Paint IBC Tote Mixers:

IBC totes are common containers for efficient paint distribution via truck trailers. However, the cubic form is less than ideal for flow patterns during mixing due to the tendency for low-flow areas in the corners and the limited top opening size. This challenge is easily overcome for relatively “thin” paint formulations, i.e. those with water-like properties such as a specific gravity at or close to 1.0 and, importantly, with low viscosity or solids content. Formulations such as these tend to mix easily with economical direct-drive mixers for totes. Tote mixer selections for these thin products include Indco’s TL-series mixers such as the TL-11A, the TL-050T or the TL-050E. These mixers are integrated into a standard tote cap and can be installed and removed from the tote by a single operator. The air-powered TL-11A and other pneumatic models require air pressure at specific volumes to achieve full rated performance. Consult Indco’s air motor guide for required air supply or speak to one of our engineers. Furthermore, the air-driven models and those with the “E” designation are generally the correct options for solvent-based formulations. Standard electric, or “T” designated models as well as the air models are both acceptable for water-borne products. The Indco BT-series such as the BT-11A or the highly featured deluxe BTC-11A direct drive tote mixers are similarly for lower viscosity applications when a tote mounting bracket is desirable.

Heavier and more viscous road paint products require heavy-duty mixers. In practice most traffic or road paints are much “heavier” than what mixers without gear reduction or larger impellers can handle. A typical specific gravity range for these paints is from 1.4 – 1.6 (11.7 – 13.4 lbs. / gallon) and viscosities of 600 – 1700 centipoise. The higher specific gravity directly determines the torque and horsepower ratings of the mixer motor and gear reducer that are required to drive larger diameter impellers. Larger impellers are required to physically contact and circulate more of the flow-resistant high viscosity material, especially in the less-than-optimal cube shaped IBC square tote. Solid mounting brackets stabilize the mixer during use and either clamp to the tote or connect to the tote cage using toggle clamps. Typical models for heavier highway and traffic paints include the BGF-400A, the BGF-150T or the deluxe BGTC-200T, Indco’s 2-horsepower electric tote mixer. Similar to the direct drive models, the specific power source is determined by the operational environment of the mixer and/or available utilities.

Highway and Road Paint 55-Gallon Drum Mixers

The 55-gallon drum is a standard container for paint and chemical products. Although not cubic in shape like IBC totes they can offer their own challenges to mixing paints or suspending settled solids. The same considerations for selection between direct-drive or gear-driven models and air-powered vs. electric models apply based on the properties of the paint. From there mixer selection may be determined by the drum configuration – closed or open top, center mounted or bung-entering, etc.

Drum mixers that are integrated into a standard 55-gallon drum lid are common for open-top drums. Models such as the Indco DLG-1A (air-powered), DLG-1T (electric) or the DLG-1E (explosion-proof electric) are suitable models for heavy-bodied traffic paints. An alternative when the drum top can be left open is to span the drum with a rigid mounting bracket with a mixer such as the BM-1T. The BM-series features pitched blade turbine impellers for maximum surface area contact for great agitation. Bung-entering models are available for low-viscosity applications but are generally not recommended for heavy traffic paints due to the small impeller sizes limited by the small openings.

Highway and Road Paint 5-Gallon Pail Mixers

For small residential roadways or parking lot jobs a 5-gallon pail may be the appropriate paint volume. Solids settle during storage and transportation making pre-application mixing an important step. There are a variety of pail mixer product formats to assist with this task. They include heavy-duty top mounted electric or pneumatic models like the FGM-1T or the FGM-1A for your heaviest and most viscous products. These mixers feature a ring-shaped frame that attaches to the outside diameter of the pail with a thumb screw and provides high-torque mixing with 9” two-bladed impellers. For mixing heavy-bodied products in a facility the MX-1TA is benchtop mounted lift-style mixer that secures the pail while agitation is provided by axial flow turbine impellers. In addition to these Indco offers a variety of handheld mixers and drill attachments for quick field applications.

Choosing the correct mixer for highway and road paint is critical to achieving the desire product consistency prior to application. Our customer service team is always available to answer any questions, or, if you are ready to discuss your needs with an INDCO engineer, visit our contact page today or call us at 1-800-851-1049 to get started today.