Kester 24-7068-6401, Solder Wire, Water Soluble, Lead Free, SAC305, 3.3%, 0.020", 331 Series
Kester 24-7068-6401, Solder Wire, Water Soluble, Lead Free, SAC305, 3.3%, 0.020", 331 Series
The Kester 24-7068-6401 is a SAC305 lead-free solder wire with water soluble 331 Series flux at 3.3% flux content and 0.020" diameter — engineered for high-reliability PCB assembly where post-solder cleaning is part of the process and residue-free joints are required.
Specifications
| Part Number | 24-7068-6401 |
| Alloy | SAC305 (96.5% Sn / 3.0% Ag / 0.5% Cu) |
| Flux Type | Water Soluble, 331 Series |
| Flux Content | 3.3% |
| Wire Diameter | 0.020" (0.508 mm) |
| Lead Free | Yes — RoHS compliant |
| Melting Point | 217–220°C (423–428°F) |
| Application | Hand soldering, PCB assembly |
Features & Benefits
- SAC305 alloy delivers excellent mechanical strength and thermal fatigue resistance
- Water soluble 331 Series flux activates aggressively for reliable wetting on difficult surfaces
- 3.3% flux content provides consistent flow and minimal spatter
- 0.020" diameter suits fine-pitch and standard through-hole work
- Residues are fully water washable — no solvents required for cleaning
- RoHS compliant and lead-free for regulated electronics manufacturing
- Ideal for IPC Class 2 and Class 3 assemblies requiring post-solder cleaning
Frequently Asked Questions
What does "water soluble" mean for solder wire flux?
Water soluble flux (like Kester's 331 Series) is an organic acid-based flux that activates strongly during soldering and leaves residues that must be cleaned with deionized water after soldering. It is not suitable for no-clean processes — cleaning is required to prevent corrosion from residual flux.
What is SAC305 solder alloy?
SAC305 is the most widely used lead-free solder alloy, composed of 96.5% tin, 3.0% silver, and 0.5% copper. It offers a good balance of mechanical strength, thermal fatigue resistance, and wettability, and is the industry standard for RoHS-compliant PCB assembly.
When should I use 0.020" diameter solder wire?
0.020" (0.508 mm) is a versatile diameter suited for both fine-pitch SMD rework and standard through-hole hand soldering. It provides good control without depositing excess solder on small pads.
Is post-solder cleaning required with this product?
Yes. The 331 Series water soluble flux leaves ionic residues that are corrosive if left on the board. Cleaning with deionized or DI water within the recommended time window after soldering is required for reliable long-term performance.
Is the Kester 24-7068-6401 suitable for IPC Class 3 assemblies?
Yes. When used with a validated cleaning process, SAC305 wire solder with water soluble flux is appropriate for high-reliability IPC Class 3 applications including aerospace, medical, and defense electronics.
