Differences Between Welding and Brazing
Brazing Isn’t Welding; Brazing Requires Much Better Cleaning
Brazing is regulated by the American welding society AWS which is about as good a place as any to put it. However there are differences.
Brazing requires a much higher standard of cleanliness than welding does in order to be successful.
For over 30 years I have been solving brazing problems by getting people to change their cleaning methods.
Many people get successful welds without any cleaning at all. Good welders will remove all oils, greases, dirts and other contaminants. They may do this with something like an alcohol or an acetone wipe.
Cleaning preparations that work for welding may not be good enough for brazing. In brazing, any layer of oil, grease etc. left can seriously interfere with the brazing process.
In a very simple example of welding you will take two pieces of the same kind of steel and melt them together. This happens at about 2500° F. In addition the act of welding and heating the parts causes airflow. If you have traces of oil left on the steel it gets burned off and the fumes disappear. If minute amounts of the burned oil get mixed in with the steel it doesn’t cause any problems.
Brazing carbide usually occurs around 1350 F or about half of welding temperature. In addition the brazing process occurs between two parts so any oil left on any parts stays right where it is. If you are brazing carbide to steel and the steel is not entirely clean you will have a layer of burnt oil between the braze alloy and the steel.
Wiping with a solvent may or may not be enough. A much better technique is to use a strong caustic or detergent. The solvent just dilutes the oils and greases. The caustic or detergent actually breaks down the oils and greases so they can be rinsed away.
For best results in Brazing try MEGA Flux. It has gone through extra processing to eliminate any particles that may get between the steel and carbide during the brazing process to weeken the braze joint and has 78% better cleaning properties over standard and purified flux.
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