Non-Corrosive Fluxes

See chart below. Fluxes are classified as Non-Corrosive when their residue after soldering will not corrode and eventually destroy the joint if allowed to remain. Generally incorporating a rosin base, these fluxes contain mild organic acids which are neutral at room temperature but become slightly acidic upon heating. Neutral, rosin fluxes are particularly useful in electrical applications, where their non-conductive, non-corrosive residue may be safely left on the assemblies.

Intermediate Fluxes

See chart below. These fluxes usually consist of mild organic salts, with considerably stronger fluxing action than non-corrosive types. Residue after soldering is normally not harmful to the soldered joint. However, residue should be removed whenever possible, as moisture in the atmosphere may initiate corrosion.

Corrosive Fluxes

See chart below. Most corrosive fluxes contain active inorganic acids and salts. Due to their increased strength and ability to quickly remove surface oxides, these fluxes are ideally suited to high-speed, automated soldering operations. Although corrosive fluxes generally produce the most reliable soldered joints, their residue after soldering must be removed, or it will eventually attack and destroy the joint.