SUPERFLOW Black Brazing Paste Flux – 1 lb Container

High-temperature brazing flux for silver and phos-copper brazing alloys.
SUPERFLOW Black Brazing Paste Flux is a high-temperature, general-purpose brazing flux designed for applications requiring higher temperatures or longer brazing cycles. It is commonly used with silver brazing alloys and compatible phos-copper brazing alloys.

The smooth black paste is commonly used for brazing compatible combinations of stainless steel, carbides, nickel alloys, steel, copper, brass, and bronze. Its extended active temperature range makes it especially useful for demanding brazing operations where a standard white flux may not provide the required temperature range or cycle time.

Package Size: Supplied in a 1 lb (16 oz) container.

Key Features

• High-Temperature Formula: Designed to remain active through higher brazing temperatures and longer heating cycles.
• Wide Active Range: Active from 1050–1700°F (565–925°C).
• AWS FB3-C: Classified to AWS A5.31 FB3-C.
• Silver Brazing Alloys: Designed for use with compatible silver brazing filler metals.
• Phos-Copper Alloys: Can also be used with compatible phos-copper brazing alloys where flux is required.
• Black Paste: Smooth consistency makes application to prepared joints easy.
• Multiple Base Metals: Commonly used with stainless steel, carbides, nickel alloys, steel, copper, brass, and bronze.
• Water-Soluble Residue: Flux residue can be removed with hot water after the brazed assembly has cooled.
• Stable Consistency: Formulated to resist hardening and crystallization and retain its smooth texture for a minimum of one year.
• 1 lb Container: Supplied in a 16 oz jar.

Designed for Higher-Temperature Brazing

SUPERFLOW Black Brazing Flux is Washington Alloy's hi-test brazing flux for applications involving higher temperatures and longer brazing cycles. Its active temperature range extends to 1700°F (925°C).

This makes the black flux particularly useful when the brazing operation requires more temperature capability or a longer heating cycle than a general-purpose white brazing flux.

Common Applications

SUPERFLOW Black Brazing Paste Flux is commonly used for compatible brazing applications involving:

• Stainless steel
• Carbides
• Nickel alloys
• Steel
• Copper
• Brass
• Bronze
• Compatible dissimilar-metal joints
• Silver brazing alloy applications
• Higher-temperature brazing operations
• Longer brazing cycles

Physical Data

How to Use SUPERFLOW Black Brazing Flux

SUPERFLOW Black Brazing Paste Flux may be used directly from the container. If a thinner consistency is required, water may be added to thin the paste.

For best results, heat the flux indirectly by bringing the base metal up to the required brazing temperature rather than concentrating the flame directly on the flux.

After brazing, allow the assembly to cool and clean the remaining water-soluble flux residue using hot water at approximately 140°F (60°C).

Black vs. White Brazing Flux

Selection Tip: Choose the black flux when the brazing application requires a higher operating temperature or longer heating cycle. The white flux is better suited as the general-purpose option within its specified temperature range.

Package Information

Note: Product packaging and label appearance may vary.

Frequently Asked Questions

What is SUPERFLOW Black Brazing Flux used for?
It is a high-temperature brazing paste flux designed for use with compatible silver brazing alloys and phos-copper alloys, particularly where higher temperatures or longer brazing cycles are required.

What is the AWS classification?
Washington Alloy's technical data identifies SUPERFLOW Black Brazing Flux as AWS A5.31 FB3-C.

What is the active temperature range?
The flux is active from 1050–1700°F (565–925°C).

What metals can it be used with?
Washington Alloy identifies stainless steel, carbides, nickel alloys, steel, copper, brass, and bronze among the common compatible materials.

What is the difference between black and white brazing flux?
The black flux is designed for higher temperatures and longer brazing cycles. SUPERFLOW Black has an active range up to 1700°F, compared with 1600°F for SUPERFLOW White.

How much flux is included?
This listing includes one 1 lb (16 oz) container.

Can the paste be thinned?
Yes. Washington Alloy states that water may be added when a thinner consistency is required.

How should the flux be heated?
For best results, heat the flux indirectly by bringing the base metal to the required brazing temperature.

How do I remove the flux residue?
After the brazed assembly has cooled, clean the water-soluble residue using hot water at approximately 140°F (60°C).

Will the flux harden during storage?
Washington Alloy states that it is formulated to resist hardening or crystallization and retain its smooth, creamy texture for a minimum of one year.