Surface Preparation Is Essential to Successful Brazing
Every successful braze joint starts with a clean surface. Dirt, grease, oil, scale and other contaminates inhibit capillary action, and as such are a barrier to sound braze joints.
It is a common misconception that brazing fluxes and atmospheres can clean surfaces. While this is true to some extent, this is not their intended use and cannot be used in place of actual cleaning processes. Fluxes
and atmospheres will penetrate thin oxide layers. remove oxide surface layers, and prevent the formation of oxides Fluxes and atmospheres can also reduce surface tension of brazing filler metals and form a protective cover over solidifying alloys in brazed joints. However, fluxes and atmospheres alone are ineffective in preparing surfaces for brazing.
Surface preparation can be divided into two categories – surface treatments and cleaning. Cleaning removes contamination preventing braze alloy from flowing and properly wetting. Surface treatments enhance wetting and help alloy adhere to surfaces.
For help deciding on cleaning products or surface preparations, contact us
for technical help.