asked: is there a difference of lead solder and lead-free solder wire?

A: there is no harm to the human body (as long as it is not eating), the smoke generated is environmentally friendly, pay attention to ventilation can be. Lead solder wire will only cause pollution to the environment (soil). Lead solder wire with lower melting point, better welding. Q: solder iron stick?

Answer: the soldering temperature is not enough, the tip may have impurities, increasing temperature or power test. Iron head cleaning, coating Rosin under test.

asked: occasionally a splash?

A: the composition of rosin in the solder wire is heated by an instant high temperature, resulting in a splash. The solder wire elect seldom spatter problem feedback. The temperature of welding itself is low. Iron or iron head temperature by preheating the solder joint, sending tin. Lead solder wire, welding process requirement is relatively low lead.

Q: black spot? More heating for a while dull?

A: the welding temperature is too high, the welding time is too long, will cause the rosin oxidation. Black, dull.