5520R1 - Safety-Silv 5 Phos-Copper Brazing Alloy 3/32"

Technical Specification: Harris Safety-Silv 5 (BCuP-3)

The Harris Safety-Silv 5 (SKU: 5520R1) is a copper-phosphorus-silver brazing filler metal designed for the joining of copper and copper-alloy base metals. Formulated with 5% silver, 6% phosphorus, and a copper balance, this alloy meets the AWS A5.8 classification for BCuP-3. The inclusion of silver in the matrix significantly improves the mechanical properties of the joint, specifically ductility and fatigue resistance, compared to BCuP-2 (0% silver) alternatives. This makes it a standard specification for HVAC and refrigeration piping systems where thermal cycling and vibration are operational factors.

Thermodynamically, Safety-Silv 5 exhibits a solidus temperature of 1190°F (643°C) and a liquidus temperature of 1500°F (816°C). This 310°F melting range provides the alloy with a "plastic" or semi-solid state during heating. This characteristic is technically advantageous when dealing with loose fit-ups or non-concentric joints, as it allows the operator to manipulate the alloy to bridge gaps that free-flowing eutectic alloys (like BCuP-5) cannot manage effectively. The alloy has a specific gravity of 8.25 and an electrical conductivity of approximately 9.6% IACS.

Fluxing Requirements: Due to the phosphorus content, Safety-Silv 5 is self-fluxing on copper base metals; the phosphorus reacts with copper oxides to form a fluid slag, eliminating the need for external flux. However, when brazing brass, bronze, or other copper alloys, a reactive flux such as Stay-Silv® White or Black is required to dissolve surface oxides and ensure wetting. Warning: This alloy must never be used on ferrous metals (steel, iron) or nickel-based alloys, as the phosphorus will react with iron/nickel to form brittle intermetallic phosphides, leading to joint embrittlement and failure.

This product is supplied in a 1 lb rigid tube containing 3/32" (2.4mm) diameter rods, each 20 inches in length. The packaging ensures moisture protection and physical integrity of the rods during storage and transport.