Disadvantages of Brazing -
1. Size limitation of the parts to be brazed is of major importance. Since the outer area to be brazed must be heated, large cast sections or large heavy plates cannot be easily brought up to temperature.
2. Brazing requires tightly mating parts to ensure capillary flow of the filler metal. This involves expensive machining to attain the desired fit.
3. Flux residues if not properly removed can cause corrosion.
4. Brazed joints do not give satisfactory results when used at elevated temperatures.
5. A certain degree of skill is required to perform the brazing operations; personnel limitations may rule out the process.
6. Very large assemblies, although brazable, may be made more economically by welding.
7. Brazing fluxes and filler rods may evolve toxic fumes and poisonous vapours.
