Aluminum Flux for Brazing Aluminum & Dissimilar Metals

Aluminum flux is selected based on material compatibility, joint configuration, and the temperature range required during the brazing process. Proper flux selection helps maintain surface condition during heating and supports consistent results when working with aluminum and dissimilar metals.

Available in multiple forms and application methods, aluminum flux can be matched to specific process requirements, giving you flexibility across different brazing setups.

Aluminum Flux for Clean, Reliable Brazing Results

Aluminum flux is required to remove oxide layers and allow filler metal to properly wet and bond to aluminum surfaces. Without the correct aluminum brazing flux, aluminum will not join correctly, leading to weak or failed joints. This makes flux for aluminum brazing essential when working with aluminum or dissimilar metals.

At WeldingMart, you can buy aluminum flux in the forms and sizes needed for your process. Our in-stock selection is ready to ship, helping you keep jobs moving without delays. Whether you’re brazing aluminum-to-aluminum or dissimilar metals, we stock brazing flux for aluminum designed for clean flow, strong adhesion, and consistent joint quality.

Shop Shop All Welding Wire & Rod, browse brazing flux, or explore general purpose brazing flux for related applications.

Benefits

Removes oxide barriers so aluminum can properly bond, preventing weak or failed joints
Supports smooth filler metal flow and joint strength, reducing rework and inconsistency
In-stock aluminum brazing flux ready to ship, keeping projects on schedule

Frequently Asked Questions

Why do I need a flux specifically made for aluminum brazing?

Aluminum forms a tough, tenacious oxide layer almost instantly on any exposed surface. Standard brazing fluxes that work on copper or steel cannot dissolve this oxide layer. Aluminum brazing fluxes (AWS Type 1) contain chlorides and fluorides formulated to break down aluminum oxide at temperatures in the 700–1190°F (371–643°C) range, which allows the filler metal to wet the base metal and flow into the joint.

What aluminum alloys can be brazed with flux, and which can't?

The aluminum alloys brazed most successfully are the 1XXX and 3XXX wrought series, plus low-magnesium 5XXX alloys. The 6XXX series (including 6061 and 6063) are also commonly brazed. High-magnesium alloys (higher 5XXX), and the 2XXX and 7XXX series, are generally not brazeable by flux methods because of poor filler metal wetting or because the alloy melts too close to brazing temperature.

Do I have to remove the flux residue after brazing aluminum?

Yes — aluminum brazing flux residues are corrosive and must be removed completely and quickly after brazing. Leaving flux on the part will cause corrosion that can penetrate the joint over time. Hot water scrubbing, followed by a dilute acid or alkaline rinse, is the typical cleaning method. Trapped flux in inaccessible recesses is a key reason why joint design must allow full flux displacement by molten filler metal.

Can I use aluminum brazing flux on dissimilar metal joints, such as aluminum to copper?

Brazing aluminum to copper or other dissimilar metals is possible but requires careful filler and flux selection. The flux must be compatible with both base metals and remain active throughout the brazing temperature range. AWS Type 1 flux (chlorides/fluorides) is designed for aluminum base metals and compatible BAISi filler metals. Consult the flux and filler metal manufacturer for specific dissimilar-metal joint recommendations.