WF-9942 No-Clean Wave Solder Flux (1 Gallon)
WF-9942 is a highly active no-clean wave solder flux designed for use with through-hole and mixed-technology assemblies. It has been effectively used in both tin-lead and lead-free soldering operations. WF-9942 is a second generation no-clean flux designed to meet the requirements of J-STD-004. Although not specifically designed for lead-free soldering (third generation no-clean) or to the requirements of the later J-STD-004B (fourth generation no-clean), WF-9942 has been successfully and reliably used to assemble millions of circuit boards for the last 15 years. WF-9942 exhibits very good SIR and ECM results when tested to the J-STD-004 and Telcordia GR-78 requirements. A rosin-free fourth generation product comparable to the WF-9942 is Indium Corporation’s WF-9958.
Physical Properties
WF-9942 is almost colorless, indicating that it is rosin-free. The solvent blend ensures even distribution of flux solids both during storage and during spray flux deposition. The specific gravity of WF-9942, 0.828 @ 25°C, is measurably higher than that of pure isopropyl alcohol. However, in contrast to higher solids content fluxes, specific gravity is not the best method to control the quality of WF-9942. This is because flux solids content is relatively low and small amounts of water contamination can confuse specific gravity measurements. While in-process quality control of WF-9942 is not generally required, the best method is to ensure both solids content and activity level is by acid value titration.
| Test | Result |
| Color | Clear |
| Specific Gravity @25°C (77°F) @15°C (60°F) | 0.828 |
| Specific Gravity @15°C (60°F) | 0.833 |
| Acid Value mgKOH/g flux | 36 |
| Solids Content | 4.37% |
| Flash Point (°F TCC) | 54 |
| J-STD-004A Flux Type | ORL0 |
Alcohol-based Fluxes
The main advantage of alcohol-based fluxes is that they require less preheat to drive off the solvent prior to entering the wave. This allows assemblers to run smaller wave soldering machines at a higher throughput rate. It also reduces the concern about flux that has not been completely heated inadvertently transferring to the top side of the circuit board.
Fluxes that have high solids content, as well as higher amounts of halogen, tend to be more heat-stable and solder better with a variety of board types, sizes, and thicknesses. Fluxes with lower solids contents and no rosin tend to be easier to electronically probe-test and have less visually apparent residue. Halogen content is not necessarily an indicator of final circuit board reliability since halogen types vary and rosin in the flux will enhance an assembly's surface insulation resistance.