The magnets are quite brittle. Don't let them fall on to hard surfaces (like concrete) from a height – they may shatter into sharp pieces. Straight copper pipe, at least 30cm long. 15 or 22mm ...

Running hot water can cause copper pipes to expand and grind against ... drain lines through the cleanout plug. Locate the magnet (and the pipe) under the floor using an ordinary compass, which ...

A copper pipe is a reddish-brown color ... Another way to know if you have a galvanized pipe is to bring a fridge magnet with you. If the magnet sticks to the pipe, it's galvanized.