iron
brass
copper
stainless steel
light duty
medium duty
heavy duty
any one
heat up the solder and apply the molten solder to the joint
heat up the joint and apply the solder
apply heat and solder simultaneously
apply solder before heating
glossy, bright and shiny
sufficiently large in size
grainy
flat
solder has lost tin due to repeated heating
solder has lost lead due to repeated heating
the flux has lost its characteristics due to long exposure with atmosphere
the joint is overheated in the process