S.A. Day is a leading manufacturer of brass and copper soldering and brazing fluxes for the automotive heat transfer industry. We are the premier supplier of quality copper/brass soldering fluxes. For over 40 years, S.A. Day has been supplying world-wide manufacturers of radiators, heater cores, condensers, evaporators and oil coolers with quality custom fluxes for brass and copper.

The company was founded in 1912 in Buffalo, NY and was initially involved in the production of buffing compound and polishing wheels. Soldering flux for copper/brass automotive heat exchangers became a vital part of S.A. Day's manufacturing program in the mid 1960's. Since that time, over 450 million pounds of flux have been shipped to companies in 33 countries. S. A. Day pioneered the development of the bromide based soldering flux which is still in use today.

Through constant improvements, our flux has come to be the industry standard. Flux sales are supported with a full service laboratory and a complete line of inventory.

In November 2007, Johnson Mfg. Co. of Princeton, IA acquired the flux manufacturing assets of S.A. Day. In 2016 production of the SA Day Product line was consolidated into the Iowa facility.

Soldering Fluxes for Copper/Brass