Which is stronger PVC cement or Contact cement?
Depends what you are using it on. PVC is designed to melt and weld two pieces of PVC. Contact cement won't work with PVC. Similarly contact cement is designed to laminate two surfaces like plastic or wood that will not be subjected to water or water pressure as found in an irrigation system fitted with PVC pipes. PVC cement will not work for that. Since you didn't indicate WHAT you are trying to bond, choose accordingly.
PVC. Contact cement can lose it's bond due to moisture and sufficient mechanical force. PVC cement dissolves the PVC so the two pieces' surfaces mix together and become one when the solvent flashes off (solvent weld. plastic model glue works the same way).
