ASTM B813 is the ASTM specification for water flushable liquid and paste fluxes used in soldering copper and copper alloy tube. It provides a focused technical reference for products intended to support clean, controlled soldering while allowing flux residues to be removed with water. For buyers, engineers, and quality teams, this standard helps identify flux materials that are evaluated against a common specification, supporting more consistent selection and use in copper tube joining applications.

What is ASTM B813?

ASTM B813 is a product specification that defines requirements for water flushable liquid and paste fluxes used in soldering copper and copper alloy tube. As an ASTM standard, it serves as a shared reference for the characteristics and performance expectations of these flux materials. In practice, it is used to support procurement, product comparison, and quality control when selecting fluxes for soldering tasks where water removability is an important property.

Where is ASTM B813 used?

This standard is commonly used in applications involving copper and copper alloy tube soldering, especially where liquid or paste flux is applied before joining. It is relevant in technical purchasing and manufacturing workflows that specify flux performance for tube assembly and related soldering operations. ASTM B813 may also be referenced by suppliers, distributors, and evaluators who need a clear specification for products designed to be flushed away with water after use.

Why is ASTM B813 important?

ASTM B813 helps bring consistency to the evaluation and selection of soldering fluxes for copper tube work. By defining a recognized specification, it supports cleaner procurement decisions, more reliable product comparison, and better alignment between supplier claims and user expectations. It can also reduce application risk by giving quality teams a standard basis for reviewing flux suitability in systems where residue removal and repeatable soldering performance matter.

• Water flushable flux specification
• Liquid and paste flux types
• Copper and copper alloy tube soldering
• Quality control and product selection