Silver Solder Flux & Paste

In silver brazing, besides selecting the appropriate silver solder (electrode, wire, ring), the flux is equally crucial. Flux effectively removes oxides from the metal surface, promotes solder wetting and flow, thereby ensuring the strength and density of the weld. Depending on different processes and application requirements, flux materials are mainly divided into two categories:

Silver Solder Flux

Description: It exists in powder, paste or liquid form, does not contain metal fillers, and needs to be used with silver solder or welding wire.

Applications: Suitable for industrial applications such as HVAC ducts, stainless steel parts, and carbide cutting tools.

Silver Solder Paste

Description: It is made of silver alloy powder and flux premixed and is usually packaged in syringes or bottles.

Applications: It is easy to use and can be precisely applied. It is widely used for precision soldering of jewelry, electronic components and small parts.

Chalco offers both products to cover a wide range of customer needs, from large-scale industrial brazing to fine repair machining, ensuring reliable welding results under different base materials and process conditions.

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Silver Solder Flux

Silver solder flux is an essential auxiliary material in the silver soldering process. It is commonly available in powder, paste, or liquid form and must be used in conjunction with silver solder rods, solder wires, or solder rings.

Common types of Silver Solder Flux:

• White Flux (General Purpose White Paste): Activation temperature range 500–800 ℃, easy to clean residue, suitable for general welding needs such as HVAC copper pipes and stainless steel valves, corresponding to StaySilv White Brazing Flux.
• Black Flux (High Temperature Black Paste): Activation temperature range up to 850–900 ℃, suitable for welding stainless steel, cemented carbide and high nickel alloys, corresponding to black flux for silver brazing.

Silver Solder Flux Industry Compatibility Overview

Silver Solder Flux Technology Highlights

• Wide temperature range: The general-purpose type covers 500–700 ℃, and the high-temperature type can reach above 850 ℃, meeting the welding needs from copper pipes to stainless steel and hard alloys.
• Compatible with a variety of materials: copper and copper alloys, stainless steel, nickel alloys, hard alloys, etc.
• Good cleaning properties: The residue is soluble in hot water, making it easy to clean and treat the surface.
• Process compatibility: Applicable to common processes such as flame, induction, and in-furnace heating.
• Standardized quality: Performance meets AWS A5.31 / ISO 9454 requirements and is comparable to mainstream international systems such as Easy-Flo®, Stay-Silv®, and Comweld.

Silver Solder Flux Product Types

Silver Solder Paste

Silver solder paste is a paste-like material premixed with silver alloy powder and flux. It contains both filler metal and oxide film remover, enabling brazing in a single operation. Common packaging forms are syringes or bottles, facilitating application and precise dosage control, making it ideal for small-part processes and precision assembly.

Silver Solder Paste Industry Compatibility Overview

Silver Solder Paste Technical Highlights

• Alloy and flux integrated, simplifying the process.
• Syringe application allows for precise operation and reduces waste.
• The weld seam is smooth and dense, which facilitates subsequent polishing or electroplating.
• Stable formula ensures consistent solder joint quality.
• Diverse packaging options to meet different needs

Silver Solder Paste Product Types

Technical Specifications of Chalco silver solder flux & paste

Our silver soldering flux and silver soldering paste undergo rigorous process design and quality testing, and possess the following technical parameters:

Operating temperature range: 500–925 ℃, meeting the needs from low-temperature jewelry repair to high-temperature stainless steel and hard alloy welding.

Compatible base materials: copper and copper alloys, stainless steel, nickel alloys, cemented carbide (not recommended for aluminum, magnesium, and titanium).

Compliance Standards: Complies with AWS A5.31 / ISO 9454 flux classification standards. The silver solder paste corresponds to common silver-based solder standards AWS A5.8 / ISO 17672 (such as BAg-7 / Ag156).

Residue handling: White general-purpose residue can be cleaned directly with hot water. High-temperature residue has strong temperature resistance, so it is recommended to remove it promptly after welding to avoid corrosion.

Process compatibility: Applicable to various welding methods such as flame, induction, and furnace heating.

Environmental protection and safety: Low halogen, low smoke, RoHS and REACH compliant, suitable for environmentally sensitive applications.

Chalco silver solder flux & paste Supply capability

Chalco not only offers standardized products, but also provides flexible customization to meet customer needs:

Flux vs Paste Comparison & Selection Guide

FAQ (Frequently Asked Questions)

Q1: Is flux always necessary for silver brazing?

A: Yes. Flux removes the oxide layer on the surface of the base metal, ensuring good wetting of the solder. Otherwise, slag inclusions or incomplete welds are likely to occur.

Q2: What is the difference between Silver Solder Flux and Silver Solder Paste?

A: Flux is a simple flux and needs to be used with soldering rods/wires; Paste is a premix of silver powder and flux, which can be used directly for soldering.

Q3: How to choose between low-temperature and high-temperature products?

A: Low-temperature products are recommended for heat-sensitive components (jewelry, electronic devices); high-temperature products are recommended for high-strength base materials such as stainless steel and hard alloys.

Q4: Does the welding residue need to be cleaned?

A: Cleaning is recommended. White, general-purpose residue can be dissolved directly in hot water. High-temperature residue is more heat-resistant and needs to be cleaned promptly after welding to prevent corrosion.

* Chalco has a complete silver soldering material supply chain, providing both standardized products and customized solutions for customers.

Contact us now to get a silver soldering flux and solder paste solution tailored to your process.

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