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Selection Guides
Grade selection depends mainly on base metal, process and downstream requirements. The notes below summarise CNOFC technical literature; send samples for a trial weld on difficult jobs.
指南 01 · Flux Selection Guide
- Match flux activity and solids content to the base metal (copper, nickel, tin-lead) and the process (wave, dip, hand soldering, tinning, pre-coating).
- For high-density double-sided boards and fine pitch, use low-solids no-clean grades (F118 series): little residue and in-circuit testing allowed.
- Difficult metals such as aluminium and stainless steel need dedicated fluxes (F105 / F107); plain rosin grades will not wet reliably.
- For water-wash processes choose F101; for pre-coating lines choose the F114 pre-coat grade.
- Recommended wave sequence: prepare, spray flux, pass the wave, air-cool, inspect and touch up.
指南 02 · Paint Stripper Selection Guide
- Room-temperature immersion grades (CC-2) suit bulk stripping of small parts.
- Brush grades (CC-3A / CC-3B) suit local stripping, large parts that cannot be immersed, and on-site rework.
- Magnet-wire grades (CC-4B / CC-4T) handle 130-220C class enamel and leave the wire ready for soldering.
- Universal stripping powder (CC-4P) tackles stubborn thick, powder and multi-layer coatings at room temperature with no evaporation.
- ABS / PS / PC parts need the plastic-safe grade (CC-2X); aggressive solvents attack the substrate.
- Note: PCB solder mask must be removed before curing; cured mask cannot be stripped. Dispose of spent liquor and residue per local rules.
指南 03 · Solder Alloy Selection Guide
- For general lead-free work choose low-cost SnCu0.7 (S157); for high reliability choose SnAg / SnAgCu (S105 / S154).
- For low-temperature or heat-sensitive assemblies use SnBi58 paste (P3 series), melting around 138C.
- For leaded work the Sn63/Pb37 eutectic (P1 series) gives the widest process window and bright joints.
- Adjust flux core content to the process: medium-high for hand and rework, low and low-spatter for automatic soldering.
- For wave solder pots with heavy oxidation, pick anti-oxidation grades (S105(kk), S204(nc)) to cut dross.
指南 04 · Plating Additive Guide
- For chromium plating use the 3rd-generation wide-temperature low-chrome grades (TCR-21 / TCR-21A): wide bath-temperature window, higher current efficiency, lower chromic acid consumption.
- Match hard chrome and decorative chrome to TCR-22 and TCR-1 respectively, and control make-up separately.
- For zinc, keep alkaline (cyanide / cyanide-free) and acid KCl brighteners strictly separate.
- Degrease thoroughly before plating (alkaline degreaser); aluminium needs etching and desmutting first or adhesion suffers.
- Follow with the matching passivation / seal, and adjust free acid and accelerator before phosphating.
FAQ
- Q: Is no-clean flux really residue-free? A: F118 leaves very little transparent, non-corrosive residue with high insulation resistance, so normal consumer electronics skip washing. Military, medical, high-voltage or conformal-coated boards should still be cleaned.
- Q: Can leaded and lead-free fluxes share a line? A: F118 suits both, but mixing alloys in one pot changes composition - drain the pot first or follow the HS-1A dross-reduction procedure.
- Q: Can stripped magnet wire be tinned directly? A: Yes - CC-4B / CC-4T leave a clean surface ready for tinning, no sanding needed.
- Q: Too much dross? A: Use HS-1A dross reducer online in the wave pot to return oxide to solder and cut tin consumption.
- Q: Samples and test reports? A: Yes - tell us your base metal and process; standard grades ship in 1-3 working days.