In renovation, different times coexist. In plumbing, cast iron, fiber cement (now forbidden), lead (also prohibited), steel, copper and, today, plastic have been used in turn to produce discharge. It is sometimes necessary to connect two pipes with different materials.
For a PVC drain to be connected to an existing copper network, a special fitting is needed because the copper is soldered, while the plastic sticks.
Remove the rubber seal
On a PVC pipe, the rubber seal seals. It must be removed to mount the fitting, as it is welded to the copper vent by soft tin solder.
Run soft solder
Soft soldering is performed with a gas torch.
First put a thin layer of tin on the fitting: it is tinning.
Then heat the fitting to the flame until it changes color.
Spread the flame away and immediately present the tin wire. If the copper is hot enough, tin melts instantly. Place the filler metal all around the fitting.
Wipe the tin
Immediately wipe off the tin with a thick dry cloth to obtain a thin and even layer, without extra thickness.
Protect your hands with gloves to prevent burns.