A person who joins metal parts together using solder.
A solderer is someone who is good at working with metal and making things stick together.
Examples:
The solderer fixed the broken metal.
I want to be a solderer when I grow up.
The solderer used a hot iron to join the metal pieces.
The solderer's job is to make things stick together.
The best solderers can join metal without making a mess.
The solderer's work is very important for making metal things.