DIY Solder Flux

Ian shows you how to make your own solder flux with rosin, alcohol and glycerin.

Flux is a wonderful goo that makes soldering faster and easier. In previous videos we compared different types of commercial flux (Flux off 1, Flux off 2), but did you know it’s possible to make a simple and effective flux at home? We’ll get you started, and don’t miss the giveaway at the end of the video.

Arhi shared his method of dissolving rosin into a solvent. Rosin is an inexpensive processed tree sap, used on violin bows, art, etc. It’s also the primary ingredient in many fluxes. Followup comments revealed an expired patent with a simple flux recipe:

  1. Isopropyl alcohol (60-70% by weight)
  2. Water white rosin (30-40% by weight)
  3. Glycerin (2-3% by weight)
  4. Cationic flurocarbon surfectant (0.01-1% by weight)
  5. Liquid flux is produced using a 20-65% concentration of rosin; at concentrations of 65-80% of rosin, a paste flux is produced

I’m going to have to try this. I like the idea of being able to control the consistency of the flux, which beats buying 5 different commercial products to have the same variety.


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