How to Clean a Braze Joint in Two Steps

Posted by Lucas-Milhaupt Brazing Experts on Jun 14, 2018

Once you have properly brazed the assembly, you will need to clean the brazed joint. Cleaning a braze joint is a two step process. The first step is to remove all flux residues. Second, pickle the joint to remove any oxide scale formed during the brazing process.

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Topics: Brazing Fundamentals, Flux

Stop-Off Helps Restrict Braze Alloy Flow

Posted by Lucas-Milhaupt Brazing Experts on Jul 5, 2016

 

Because of tolerances, aesthetics or joint design, you sometimes need the flow of braze alloy to be restricted-to stop its flow or keep it off a surface. Capillary dams are often designed into these parts to limit braze alloy flow. A capillary dam is when the clearance is increased to a point where capillary action no longer exists. Ideal clearances for the best capillary strengths are .000"-.002" in furnace, and .002"-.005" in open air. Anything over .012" is preferred as a capillary dam. When the assembly cannot be designed to naturally prevent braze alloy flow, a brazing aid called Stop-Off can help you prevent or guide the flow of braze allow on your assembly.

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Topics: Flux

Flux Removal: Post-Braze Cleaning

Posted by Lucas-Milhaupt Brazing Experts on May 16, 2016

 

Depending on your brazing process, you may need to perform post-braze joint cleaning to remove residual flux. This step can be crucial since most fluxes are corrosive. Post-braze cleaning is one of the Six Fundamentals of Brazing*.

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Topics: Flux, Brazing Fundamentals

Inspecting Brazed Joints

Posted by Lucas-Milhaupt Brazing Experts on Jul 11, 2014

Radiographic Examination - Discontinuity Images on Film

Examining finished joints may be the final step in the brazing process, but inspection procedures should be incorporated into the design stage. Your methodology will depend on the application, service and end-user requirements plus regulatory codes and standards.

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Topics: Flux

Liquid Metal Embrittlement

Posted by Lucas-Milhaupt Brazing Experts on Mar 6, 2014

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Topics: Flux, Copper, Stainless Steel

Warranty Statement

Posted by Lucas-Milhaupt Brazing Experts on Feb 3, 2014

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Topics: Flux, Solder

Hi-temp Flux Blog

Posted by Lucas-Milhaupt Brazing Experts on May 7, 2013

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Topics: Oil & Gas, Flux

Stages of Flux Video

Posted by Lucas-Milhaupt Brazing Experts on Apr 12, 2013

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Topics: Flux

Stop-Off Blog

Posted by Lucas-Milhaupt Brazing Experts on Mar 19, 2013

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Topics: Flux, Brazing Fundamentals

Handy One® Improves Joint Quality and Reduces Flux Usage

Posted by Lucas-Milhaupt Brazing Experts on Sep 19, 2012

Brazing Methods
Brazing methods range from torch brazing in open air to vacuum furnace brazing.  Torch and induction brazing are the most common, using an Ag-Cu-Zn alloy to form joints. Oxides form on surfaces of base metals in open air, prohibiting the filler metal from wetting the assembly properly.  Flux, applied before brazing, prevents oxidation from occurring and dissolves the oxides present on the base metal surfaces.  Flux also allows the braze alloy to wet the base metal and flow into the joint interface. Fluxes come in forms including pastes, slurries, liquids, and powders.  Typically, these require a separate application when brazing with solid wire.  Manual fluxing increases cycle time and introduces a variable which can affect joint consistency and quality, increase post-braze clean-up time, and pose safety concerns.   
                                                                    
What is Handy One®?
Handy One® flux-cored products offer flux inside a braze alloy wire, so no external flux application is required.  This condenses the two steps of applying flux and alloy into one step, with the product being either applied during heating or placed in the joint region prior to brazing.  Use of Handy One® helps limit inconsistencies in flux application, reduce brazing process times and safety/environmental concerns, plus improve braze joint quality.
Figure 1 shows the states of brazing with Handy One®.  After a flux-cored braze ring is placed on the assembly (1), heat is applied and the flux inside the wire becomes molten, flowing out of the wire into the joint interface (2).  The flux that flows into the joint interface prevents and removes oxide formation during heating, allowing the molten braze alloy to wet the base material and capillary into the joint (3). Capillary attraction pulls the alloy through the joint, forcing the flux out of the joint interface, and completes the braze (4).
Handy One® is available with several filler metal options.  Click here to determine the correct product for your operation.

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Topics: Flux