Basic steps for good brazing

STEP N° 2 APPLICATION OF FLUX

To keep the cleanliness obtained in step N°1 during the whole brazing procedure, FLUX is to be used, metallurgical designation for chemical deoxidants that must be applied on the surfaces before brazing.

What's the flux function?

The flux performs as a deoxidant with no grease removing properties. When heated, the metal parts tend to form oxides quickly as a result of the heat. If these oxides stay on the surface on the metals they prevent the capillary action from performing, hence the capillary fluidity of the filler metal. The flux, especially under heat, reacts immediately against the metal oxides dissolving and, at the same time, avoiding the formation of new ones. The flux creates a protective cover on the metallic surface by acting as an actual insulation between the surface and the atmosphere, reacting with the oxygen from the torch also.

The most common flux is in paste. ARGENTA WELDING TECHNOLOGY manufactures it as ARGENTA "U".. This flux is easily applied with a brush and it can be used in any position.

It's always better to apply the flux in little excess. By doing so, the residuary flux ends partially loaded with oxides which allows for an easy removal with water. When not enough flux is applied, the residual is fully loaded with oxides becoming solid just like a crystal, difficult to remove and hardly soluble to water.

 

 

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