Difference Between Soldering And Brazing
Solder and brazing are similar, in both cases a filler material having the melting point much lower than parent material added into the gap between work-pieces by capillary action. The characteristics of this metal joining method may vary in some special application.
| 
Soldering | 
Brazing | 
| 
The solder joints are the weakest joints.
  They are not intended load. | 
This
  can be used to carry the burden to some extent. 
Properly made
  brazing may be stronger than the metal to be
  joined, but they are not as strong as welded joints. | 
| 
Soldering is done by heating filler metal up to 450 degrees Celsius (840 °F). | 
Brazing joins
  materials by heating the filler metal with the
  melting point above 450 degrees Celsius,
  but below the melting point of the base
  metal.  | 
| 
An alloy of lead and
  tin known as solder used as  filler material. | 
Alloys of copper with
  zinc, silver and aluminium are the common
  brazing filler material. | 
| 
Close /
  fine contact between the base material
  not necessary | 
Fine
  contact of the base metal is necessary; they should not have an interfering
  layer between them. | 
| 
It has
  the least impact on the base material. | 
In the brazing of
  the greatest strength is achieved through some chemical reaction between
  solder alloy and metal on each side. | 
| 
Solders
  are more vulnerable to oxidation since they are
  made of the alloy of tin and
  lead. (In special cases zinc-aluminium alloys used as filler to avoid
  this problem) | 
Susceptible to
  oxidation but not much as in soldering. | 
| 
The commonly used
  fluxes for soldering are zinc chloride and HCl. | 
Fluxes are fluorides,
  chlorides, Borax and boric acid. | 
| 
Lower cost,
  inexpensive filler material, low temperature virtually no cleaning required
  after soldering. | 
Costlier than
  soldering. | 
| 
It
  is particularly useful when the heat can damage or deform the materials.
  Commonly electrical components are soldered to prevent heat damage. | 
Brazing used for joining
  dissimilar metal, fastening of pipe fittings and leak proof joints. | 

 
