Indium Blog

Flux Pens for Hand Soldering Solar Cells

A few months back, while discussing tricks for hand soldering c-Si solar cells, I mentioned flux . One tip I didn’t mention is how to APPLY flux before soldering.

Tabbing fluxes are commonly sprayed and dipped in automated processes, but flux pen application is best for hand soldering. Flux pens are small plastic containers with a spring loaded felt tip at one end. With a slight amount of pressure, the tip allows flux to wick through the felt and onto the cell.

  • Since the tip valve closes between uses, evaporation is kept to a minimum.
  • The unit is disposable; there are no needles or micro valves to keep clean.
  • Application is uniform so there is less chance of flux inconsistencies.

I use flux pens for non-automated testing of fluxes.

If you are interested in trying one of our fluxes in pen form, send us an email at


Authored by previous Indium Application Manager Jim Hisert