Alcohol-Based Flux
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.
WF-9958 Wave Solder Flux
Indium Corporation’s new WF-9958 soldering flux is an updated version of Indium’s best-selling WF-9942, designed to conform to the more rigorous standards of J-STD-004B Type ORM0. It has no intentionally added halogens, no rosin, and exhibits exceptional hole fill as well as pin-testing performance that can only be achieved with a rosin-free material. In addition to exhibiting excellent soldering performance on a wide range of board finishes and board types, WF-9958 also passes the updated and more rigorous reliability requirements of the J-STD-004B Surface Insulation Resistance (SIR) and Electromigration (ECM) tests.
Features
- Halogen-free per J-STD-004B*: To be halogen-free per J-STD-004B, the formula must contain less than 500ppm of any kind of halogen, ionic or non-ionically bonded chlorine, bromine, or fluorine. This is new to J-STD-004B since fluxes that conform to the original J-STD-004 or J-STD-004A may still contain halogens that only disassociate at soldering temperatures, but leave a residue that contains ionic halogen.
- Light-colored, low-residue, and rosin-free flux and residue for enhanced pin-testing performance: Rosin, modified rosins, and resins do contribute to enhanced heat stability for thick or difficult-to-solder boards and for the encapsulation of flux activators. However, the rosins and resins interfere with probe testability.
- Tested compatibility with Hot Air Solder Leveled (HASL), Immersion Silver, Electroless Nickel Immersion Gold (ENIG), and Organically Solder Preserved (OSP) Copper surfaces.
- Tested for use with all common lead-free and tin-lead alloys, including: SAC305; SAC105; SAC0307; silver-free tin-copper plus additive alloys, such as Indium Corporation’s Sn995; 96.5Sn/3.5Ag; 63Sn/37Pb; 60Sn/40Pb; and many others.
Physical Properties
Indium Corporation’s WF-9958 flux has almost no color when received in its shipping container. This is because it is anhydrous isopropyl alcohol-based with less than 5% solids and no dark-colored components, such as rosin or modified rosins. Because the flux is anhydrous alcohol-based and has low solids, the specific gravity is very close to that of alcohol and the same flash point as pure isopropyl alcohol. No halogens, ionic or nonionic (as are in some J-STD-004- and J-STD-004A-compliant fluxes), have been added to WF-9958. If there are any halogens in WF-9958, they are minor contaminants of other components and will not exceed 50ppm of the total flux. Quality control of WF-9958 during use is generally not required. However, if desired, acid value is the best parameter to monitor, since it will give both an indication of solids content and flux activity.
| Test | Result |
| Specific Gravity @ 25°C (77°F) | 0.798 |
| Specific Gravity @ 15.5°C (60°F) | 0.805 |
| Acid Value mgKOH/g flux | 28.5 |
| Acid Value mgKOH/g flux solids | 571 |
| Solids Content | 4.99 |
| Flash Point | 12°C |
| J-STD-004B Flux Type | ORM0 |
| Total Halogen | <50ppm |
Shelf Life
The shelf life for this product is 2 years in an unopened container stored at less than 32.2°C (90°F). Shelf life for an opened container will vary depending on storage conditions, including open time, temperature, and humidity. For the longest shelf life of an opened container, replace the cap to reduce alcohol evaporation and store it in a cool, dry environment.
Residue Removal Recommendations
All of Indium Corporation’s no-clean fluxes, including this formula, are designed to be electrically safe under normal consumer electronic and telecommunication operating conditions. Unless otherwise specified, electrically safe means that the post soldering residues pass J-STD-004B SIR and ECM testing. However, it is understood that some customers desire to remove residues for cosmetic reasons, improved in-circuit testing, improved compatibility with specific conformal coatings, or where the operating parameters of the circuit board may be in extreme conditions for a prolonged period.
Indium Corporation Compatible Products
- Solder Paste: Indium8.9HF
- Cored Wire: CW-807
- Flux Pen: FP-500 (rosin-containing), NC-771 (rosin-free)
Indium Corporation’s wave soldering fluxes have been designed to be fully compatible with our solder paste, cored wire, and rework flux, and are also expected to be compatible with many of our competitors’ products. For example, WF-9958 Wave Solder Flux is not only compatible with Indium8.9HF Solder Paste, but also with our 5.2LS, 8.9 series, 92 series, and 10 series. Indium Corporation determines compatibility primarily by matching flux chemistry. However, a select number of the wave, reflow, and rework product combinations have been thoroughly tested to ensure that the combined flux residues meet the electrical and reliability requirements of IPC J-STD-004B. Please contact Indium Corporation Technical Support if you are interested in knowing about these fully-tested combinations.