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Press Room | Kester

ITASCA, IL — August 26, 2015
Contact: Michelle O’Brien, Marketing & Communications Specialist

Kester is proud to announce three products, NP505-HR, NF372-TB and 985M, passed Bono Testing. Third party laboratory testing certified that all products passed the Bono test criteria with corrosion factor (Fc) values of less than 2.0%, indicating no corrosion in the residues.

Kester 985M has been Kester’s top selling no-clean flux for several years. NP505-HR is a new zero-halogen, lead-free, no-clean solder paste formula developed specifically for high reliability applications. NF372-TB is a new zero-halogen, no-clean, low solids liquid flux designed to withstand long dwell times and high preheat temperatures needed in thick board assemblies. “These two new products were each designed to meet the industry’s increased demand for high reliability in demanding applications, and passing the Bono test is another positive endorsement for our innovative portfolio,” stated Dr. Bruno Tolla, Kester’s Global R&D Director.

In the Bono test, the resistance measurements are used to calculate the corrosion factor (Fc) that is given as a percentage. While SIR and ECM tests are recognized by IPC as a way to evaluate paste or flux residue corrosiveness after reflow, the Bono test was developed and implemented in some French companies as an extra qualification criteria. The Bono test also quantifies the corrosion, unlike current SIR or ECM tests. In addition to characterizing solder paste residues, the Bono test can be performed for wave soldering fluxes, repair fluxes, and tacky fluxes using the same method and same board.

For more information on these products, please visit our website or contact your Kester representative.


Kester is a global supplier of assembly materials for the Electronic Assembly and Semiconductor Packaging industries. Kester is focused on delivering innovative, robust and high-quality solutions to help our customers address their technological challenges. Kester’s current product portfolio includes soldering attachment materials such as solder paste, soldering chemicals, TSF (tacky solder flux) materials, and metal products such as bar, solid and flux-cored wire. Kester is an Illinois Tool Works (ITW) company. ITW is a Fortune 200 company that produces engineered fasteners and components, equipment and consumable systems, and specialty products. It employs approximately 49,000 people, and is based in Glenview, Illinois, with operations in 57 countries.