Series 118 Uni-Bond Mastic is a single-component, mastic waterborne acrylic coating for use on minimally prepared sound rusted steel and previously coated surfaces in a wide range of environments. It is an excellent rust-inhibitive tie coat that can be used with acrylic and solvent-borne urethane and fluoropolymer finish coats.

“With Series 118, it is possible to apply six to eight mils dry film thickness (DFT) per coat,” explained Cory Brown, Vice President of Technical Services for Tnemec. “Although it offers a fairly high standing viscosity, Series 118 sprays on easily with dry-fall characteristics that reduce the potential for overspray issues on buildings and surrounding property.”

Series 118 has been specified as an overcoat for steel water tanks, vessels and other industrial and architectural metal substrates. Surface preparation consists of power washing steel at 5,000 psi and some mechanical hand or power tool cleaning to remove loose rust, scale and deteriorated coatings to obtain a sound surface for coating.

In addition to its strong adhesion properties, Series 118 offers 200 percent elasticity for excellent flexibility and impact resistance. “The coating has excellent elongation, enabling it to expand and contract with the substrate as the temperature varies,” Brown reported.

In Cortland, IL, Series 118 was specified for the exterior of an elevated municipal water storage tank where a limited budget prevented the owner from abrasive blasting exterior steel. “After a severe winter of freeze-thaw conditions, the coating system maintained its original appearance,” Brown observed.