Saturday, November 16, 2013
Define Brazing to Stop a Muffler Leak in a Car
One of the most important functions of a cars exhaust system is to protect the occupants of the vehicle from hazardous fumes. If the exhaust system leaks, carbon monoxide and other waste gases can collect in the cabin and harm or kill the passengers. Because of the abuse and exposure suffered by the exhaust system, faulty or leaking parts are usually replaced. If the exhaust system is sound enough, it can be repaired.
Braze Welding
Braze welding is a way to join two metals with different melting temperatures. The filler metal has a lower melting point than the base metal. Small holes in a muffler may be patched by braze welding filler material into the holes. Larger holes in a muffler may be repaired by braze welding patches of steel over the holes.
Brazing
Brazing is similar to braze welding in that the filler material has a lower melting temperature than the base metal. The difference between brazing and braze welding is that in brazing the filler metal is drawn into the joint by capillary action. In plumbing, this process is called "sweating" a joint. Exhaust pipes can be repaired at the joints by brazing.
Why Does the Shop Want to Replace Instead of Repair?
Repairs to any metal can only be done where the metal is in good shape. The exhaust system of a car is subjected to abuse from both the inside and the outside of the system. The temperatures of exhaust gases are high enough to weaken any metal. Cars driven in areas that use salt to clear snow from the road can suffer corrosion very quickly. If an exhaust system is more than two or three years old, it probably is not a candidate for repair.
Benefits of Braze Welding or Brazing
Joining metals with either a brazed or a braze-welded joint can result in a stronger joint than traditional welding because of the difference in melting points between the two materials. If steel is heated to near its melting point then allowed to cool slowly, it becomes weak. With either of these techniques, the steel never gets hot enough to be damaged.
