OP started out talking about plumbers; if you want to meet plumbers (or their friends) at networking events, you're going to have to start attending builder's c

OP started out talking about plumbers; if you want to meet plumbers (or their friends) at networking events, you're going to have to start attending builder's conferences. And even if you do that, the people you're likely to meet will be businessmen, not tradesmen. Tradesmen work, and when they're not working, they're either getting training or they're on holiday. They don't do "events".