POST-CLEANING
(Surface Preparation)
A significant benefit of the Paste Process is that type and amount
of flux may be carefully controlled, yielding minimal flux residues. Nonetheless,
flux residues of a corrosive nature must be removed to prevent damage to the joint over an
extended period. The following additional guidelines are offered.
Rosin Type Flux
Residues - Generally, these are non-corrosive and may be left on the part without
damage to the joint area. If residue removal is desired, it may be removed using alcohols
or chlorinated hydrocarbon solvents (1:1:1 trichloroethane) or combinations of both
families.
Activated Rosin Fluxes - Some rosin activators will cause corrosion under
unusually hot or humid conditions. most may be removed using alcohol or chlorinated
hydrocarbon solvents (1:1:1 trichloroethane) or combinations of both families.
Oily or Greasy Flux Residues - Generally may be removed with an alkaline
cleaner such as Fuze-Clean S.
Intermediate and Corrosive Solder Fluxes (Halides) - These fluxes leave a
fused residue which absorbs airborne moisture, causing a slow chemical reaction at the
joint. Removal is generally accomplished by thorough washing in warm detergent water, or
in hot water containing dilute hydrochloric acid, followed by hot water rinse.
Low-Temperature Brazing Fluxes - These residues may be removed with hot
water - alone or with detergents, alkaline cleaners, or acid cleaners. The most effective
method is largely dependent on the base metals involved.
High-Temperature Brazing Fluxes (Borates) - These hard, glass-like
deposits are insoluble in many cleaners. They may be cracked off, however, by quenching
the hot assembly in water immediately after brazing. A solution of dilute hydrochloric
acid may also be helpful. We offer an all-purpose brazing post
cleaner:
