Indium Blog

Indium Corporation Tabbing Flux Performance

I was recently asked to gather some data comparing Indium Corporation’s tabbing fluxes and our largest competitor’s leading tabbing fluxes. Using a new method of solder spread testing found in an upcoming issue of Global Solar Technology, two Indium Corporation tabbing fluxes were directly compared to three of the leading competitor’s fluxes.

The test consists of these simple steps:

  • Apply flux to cell
  • Dry flux on cell
  • Apply solder preforms on cell metallization
  • Reflow on a hotplate
  • Measure solder length

Finally, the measurements are plugged into the equation:

S = (Lf/Li)100-100

                   Where:         S = Increase in preform length

                                      Lf= Final solder length

Li= Initial length of preform

In the end, the Indium Corporation tabbing fluxes (GS-3434 and GS-5454) both caused the solder to spread ~44% further on a given cell – compared to only 13%, 15%, and 16% for the competitors' fluxes.

If you’d like to learn more about the test method or the results, or want help conducting your own evaluation, send me an email at

Authored by previous Indium Application Manager Jim Hisert