If you’re going to build bots, sooner or later, you’ll need to solder. If you’re going to solder, Flux becomes an essential material. Flux aids in soldering and desoldering processes by removing oxide films which form on the surface of metals being soldered. It increases the wetting ability of the solder, causing it to flow more uniformly over surfaces without balling-up (dewetting). Rosin flux is perfect for soldering electronics wires and components because the residue is non-corrosive which eliminates the need for post-solder cleaning. Waxy consistency allows for ease of use. Allows you to apply flux where you want it, and adheres well to dipped wires. Our #135 Rosin paste flux speeds up heat transfer. It takes less time to heat through and create reliable solder joints. Contains NO Zinc Chloride or Ammonium Chloride, making it a better choice for electronics soldering. Leaves minor residue that is non-conductive and non-corrosive and requires no cleaning. All rosin fluxes like our rosin paste flux leaves a protective coating over soldered connections once the soldering job is finished. Ideal for electrical repairs and connections Doesn’t need to be cleaned Type RA (Rosin-Activated) Temperature range 93°-315°C Formulated for use with tin/lead and lead-free alloy ROHS compliant Please Note: crystallization or “rosin hardening” at the surface of the flux is normal.