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Spool of .020 inch silver solder wire in cardboard box

Kester Solder

Kester Solder 24-6337-0010 Sn63Pb37 RA .020" 1 lb

SKU CH-FRVF-MC7NN MPN 24-6337-0010

One-pound spool of 0.50 mm Sn63Pb37 solder wire with RA flux core for electrical hand soldering

  • Product typeSolder
  • Fine 0.50 mm wire for precise joints
  • 63/37 tin-lead alloy melts at 183–190 °C
  • RA flux core gives instant wetting action
  • 3 % flux by weight suits production soldering
  • 1 lb spool provides ample length for extended work

Alloy and flux profile

Kester 24-6337-0010 is a leaded rosin-activated wire solder intended for electrical and electronic hand soldering on production lines. The Sn63Pb37 alloy melts between 361 and 374 degrees Fahrenheit, or 183 to 190 degrees Celsius. It suits technicians who need consistent wetting on copper pads and through-hole joints. It is not for buyers who require lead-free compliance or RoHS-conformant assemblies.

Diameter, core and spool capacity

The .020 inch (0.50 mm, 25 gauge) wire with a 66 core size delivers 3.3 percent flux by weight, giving enough material for extended rework sessions without frequent spool changes. One pound of wire provides substantial length for high-volume bench work. Users needing finer pitch work below 20 gauge or larger diameter wire for heavy power connections will find this diameter unsuitable.

Flux behaviour and residue

The RA #66/44 flux core is classified ROM1 per J-STD-004 and leaves an active residue that requires cleaning for high-reliability or conformal-coated builds. Its instant wetting action speeds up joint formation during manual assembly. Builders who prefer no-clean flux or cannot perform post-solder cleaning should select a different flux type.

How it compares

Measured against everything we stock in Soldering Irons & Stations, at today’s prices. Recalculated every night.

Price $49.99
Pricier than about 71% of the 802 comparable items (median $25.99).

Specifications

Product
Brand nameKester
Model name24-6337-0010
Product typeSolder

Questions about this item

Will the .020" diameter work with my existing fine-pitch soldering iron tips?

The 0.50 mm wire feeds smoothly through standard 25-gauge tips and melts between 183 °C and 190 °C, so most temperature-controlled irons handle it without adjustment.

How can I confirm the 63/37 alloy is flowing correctly after I set up?

A proper joint appears bright and shiny within seconds; the 3.3 % RA flux core (designation 66) gives instant wetting, so dull or grainy surfaces mean the tip temperature needs raising.

Does the 1 lb spool include any flux pen or cleaning supplies, or are they separate?

Only the Sn63Pb37 RA-cored wire on the spool is supplied; flux pens, tip cleaner and desoldering braid must be purchased separately.

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