What should be done before applying cement to a pipe?

Before applying cement to a pipe, ensuring that it is dry with no water inside is crucial. Moisture can interfere with the bonding process of the cement, preventing it from adhering properly to the pipe. If there is any water present, it can create a barrier that weakens the cement's effectiveness, leading to potential leaks or failures in the seal. Additionally, the presence of moisture can cause the cement to set improperly, compromising the integrity of the repair or installation.

Checking for stability is important for safety but does not directly affect the cement's adhesion. Heating the pipe might not be necessary and could even be counterproductive, as it risks damaging the pipe material. Applying a wide sealant could be a separate step in different contexts but is not directly related to the successful application of cement on a pipe. Thus, ensuring the pipe is completely dry is the most critical step before cement application.