What softens the joining surfaces when using Whalen solvent cementing on plastic pipe?

When using Whalen solvent cementing on plastic pipe, both primer and cement play crucial roles in the joining process. The primer is specifically designed to prepare the surfaces of the plastic pipe and fittings by softening them, allowing for better adhesion when the cement is applied. This softening process enhances the chemical bonding that occurs once the cement is applied.

The cement itself also contributes to softening the joining surfaces, as it contains solvents that dissolve the surface of the plastic, creating a fusion between the two pieces being joined. Therefore, both the primer and the cement work in tandem to ensure that the surfaces are adequately softened for a strong, lasting bond. This dual approach increases the effectiveness of the solvent cementing process, resulting in a more reliable joint.

This understanding is essential for proper application and ensures compliance with plumbing codes and best practices in pipe fitting.