PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

FLUX-CORE 66Flux,soldering

Kester Inc · NSN 3439-00-255-4571 · FSC 3439 · No Item Name Available
Verified by PartsTable
NSN 3439-00-255-4571 — this item is cataloged by the U.S. Government under National Stock Number 3439-00-255-4571. Primary manufacturer part number: FLUX-CORE 66.
Features
  • Flux,soldering — FSC 3439
  • Material for Which Formulated: LEAD TIN ALLOY
  • Specific Metal for Which Formulated: ALL METALS EXCEPT ALUMINUM
  • Content Within Each Unit Package: 2 OZ OZ
  • Nondefinitive Spec/std Data: 1 TYPE AND A FORM
  • Physical Form: PASTE
  • 6 verified cross-references
  • Primary manufacturer: Kester Inc
Applications
  • Industrial maintenance and repair
  • Government and military logistics
  • Equipment overhaul and refurbishment
General Description

The Flux,soldering, cataloged under National Stock Number 3439-00-255-4571, is classified within Federal Supply Class 3439 (No Item Name Available) of the Metalworking Machinery (continued) group. The primary manufacturer of record is Kester Inc. Government technical data includes 5 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 6 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 7 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN3439-00-255-4571
Primary Part NumberFLUX-CORE 66
Item NameFlux,soldering
FSC / FSG3439 / 34 — No Item Name Available
ManufacturerKester Inc
StatusCANCELLED
Material for Which FormulatedLEAD TIN ALLOY
Specific Metal for Which FormulatedALL METALS EXCEPT ALUMINUM
Content Within Each Unit Package2 OZ OZ
Nondefinitive Spec/std Data1 TYPE AND A FORM
Physical FormPASTE
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 7
3439-00-250-2629 INTERCHANGEABLE
Flux,soldering
3439-00-255-4566 INTERCHANGEABLE
Flux,soldering
3439-00-260-1264 INTERCHANGEABLE
Flux,soldering
3439-00-629-7489 INTERCHANGEABLE
Flux,soldering
3439-01-069-9176 INTERCHANGEABLE
Flux,soldering
3439-01-236-9572 INTERCHANGEABLE
Flux,soldering
3439-01-242-9115 INTERCHANGEABLE
Flux,soldering
Cross-Reference Index
Part NumberManufacturer
FLUX-CORE 66 Kester Inc (USA)
A-A-51145 Federal Commercial Item Description Promulgated by General Services Administration Washington DC (USA)
O-F-506 Federal Specifications Promulgated by General Services Administration Washington DC (USA)
SN60 CORE 66 Kester Inc (USA)
FORMULA 66 Kester Inc (USA)
COREN66 Kester Inc (USA)
Related Parts
3439-00-250-2629INTERCHANGEABLE
FLUX,SOLDERING
3439-00-255-4566INTERCHANGEABLE
FLUX,SOLDERING
3439-00-260-1264INTERCHANGEABLE
FLUX,SOLDERING
3439-00-629-7489INTERCHANGEABLE
FLUX,SOLDERING
3439-01-069-9176INTERCHANGEABLE
FLUX,SOLDERING
3439-01-236-9572INTERCHANGEABLE
FLUX,SOLDERING
3439-01-242-9115INTERCHANGEABLE
FLUX,SOLDERING

Frequently Asked Questions

What is NSN 3439-00-255-4571?

NSN 3439-00-255-4571 is a Flux,soldering, manufactured by Kester Inc, classified under FSC 3439 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 3439-00-255-4571?

NSN 3439-00-255-4571 has 6 cross-referenced part numbers: FLUX-CORE 66 (Kester Inc), A-A-51145 (Federal Commercial Item Description Promulgated by General Services Administration Washington DC), O-F-506 (Federal Specifications Promulgated by General Services Administration Washington DC), SN60 CORE 66 (Kester Inc), FORMULA 66 (Kester Inc) and 1 more.

What NSN replaces 3439-00-255-4571?

There are 7 known substitutes for 3439-00-255-4571: 3439-00-250-2629, 3439-00-255-4566, 3439-00-260-1264 and 4 more. Verify interchangeability with system specifications before substitution.

What are the specifications of FLUX-CORE 66?

Key specifications for FLUX-CORE 66: Special Features: NOT INTENDED FOR USE IN SOLDERING ELECTRONIC OR ELECTRICAL CIRCUITS; Material for Which Formulated: LEAD TIN ALLOY; Specific Metal for Which Formulated: ALL METALS EXCEPT ALUMINUM; Content Within Each Unit Package: 2 OZ OZ. 6 total characteristics are documented in the Federal Logistics Information System.

Is NSN 3439-00-255-4571 still in active supply?

NSN 3439-00-255-4571 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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