Kester part number 24-6337-0018 delivers Sn63Pb37 eutectic solder wire in a thin 0.025 inch diameter with 3.3% 44 Rosin Activated flux core, making it ideal for precision PCB assembly, electronics rework, and detailed through hole soldering on smaller to medium sized components. This classic tin lead alloy melts at 183°C and is a trusted choice for technicians and hobbyists who need reliable wetting and clean joints without lead-free transition costs. The thin gauge allows excellent control in tight spaces while the rosin flux provides good flow and mechanical strength, cleanup with standard flux cleaner is required. Made in the USA, this 1 lb spool offers professional grade performance for repair shops, educational labs, and production environments where proven alloy chemistry matters.
Key Features:
Alloy Composition: Sn63Pb37 (63% Tin, 37% Lead)
Diameter: .025" (0.6 mm)
Weight: 1 lb (approximately 454 grams)
Package Type: Spool (SPL)
Flux Core: 3.3% 44 Rosin Activated Flux
Melting Point: 183° C 361° F
Eutectic solder melts and solidifies at the same temperature.
.025" Diameter suitable for smaller to medium sized soldering jobs. Rosin Flux must be cleaned after use.
Ultra fine sized diameter useful for precision soldering and micro electronics.
.015" (0.4 mm)
Very fine sized diameter useful for precision soldering and jobs requiring small amounts of solder.
.020" (0.5 mm)
Fine sized diameter used for through hole and and surface mount work. Delivers a Controlled amount of solder.
.025" (0.6 mm)
Ideal for standard circuit board components where precision is needed but not ultra-fine work.
.031" (0.8 mm)
Ideal for fixing circuit boards, replacing components, and general rework. Popular for Arduino, Raspberry Pi, and DIY projects. It's a versatile diameter, often called the "sweet spot" for electronics.
.040" (1.0 mm)
Perfect for surface-mount devices (SMDs) and medium components where precision is key but more solder is needed.
.050" (1.27 mm)
Used for various tasks where a balance of flow and control is required, like general electrical repairs.
.062" (1.5 mm)
medium-thickness wire ideal for general electronics, larger through-hole components, appliance repair, automotive work, and crafts like stained glass
.093" (2.36 mm)
versatile, medium-to-thick wire used for general and heavier-duty electrical, electronics, automotive, and HVAC repairs/manufacturing.
63/37, the best, why would you use anything else. 44 (RA) preps surfaces and works great on old circuit boards. I find .025 a good diameter for through hole or sometimes larger SMD. -IPC certified tech for 10 years
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